stat, lstat, fstat: Get File Status

Fortran Library Reference

Chapter 1

Fortran Library Routines

This chapter describes the Fortran library routines alphabetically. See the FORTRAN 77 Language Reference for details on Fortran 77 and VMS intrinsic functions. All the routines described in this chapter have corresponding man pages in section 3F of the man library. For example, man -s 3F access will display the man page entry for the library routine access.

See also the Numerical Computation Guide for additional math routines that are callable from Fortran and C. These include the standard math library routines in libm and libsunmath (see Intro(3M)), optimized versions of these libraries, the SPARC vector math library, libmvec, and others.

Data Type Considerations

Unless otherwise indicated, the function routines listed here are not intrinsics. That means that the type of data a function returns may conflict with the implicit typing of the function name, and require explicit type declaration by the user. For example, getpid() returns INTEGER*4 and would require an INTEGER*4 getpid declaration to ensure proper handling of the result. (Without explicit typing, a REAL result would be assumed by default because the function name starts with g.) As a reminder, explicit type statements appear in the function summaries for these routines.

Be aware that IMPLICIT statements and the -r8, -i2, -dbl and -xtypemap compiler options also alter the data typing of arguments and the treatment of return values. A mismatch between the expected and actual data types in calls to these library routines could cause unexpected behavior. Options -r8 and -dbl promote the data type of INTEGER functions to INTEGER*8, REAL functions to REAL*8, and DOUBLE functions to REAL*16. To protect against these problems, function names and variables appearing in library calls should be explicitly typed with their expected sizes, as in:
integer*4 seed, getuid

real*4 ran

...

seed = 70198

val = getuid() + ran(seed)

...
Explicit typing in the example protects the library calls from any data type promotion when the -r8 and -dbl compiler options are used. Without explicit typing, these options could produce unexpected results. See the Fortran User's Guide and the f77(1) and f95(1) man pages for details on these options.

The more flexible -xtypemap compiler option is recommended over the obsolete
-i2, -r8, and -dbl options and should be used instead.

You can catch many issues related to type mismatches over library calls by using the Fortran compilers' global program checking option, -Xlist. Global program checking by the f77 and f95 compilers is described in the Fortran User's Guide, the Fortran Programming Guide, and the f77(1) and f95(1) man pages.

64-Bit Environments

Compiling a program to run in a 64-bit operating environment (that is, compiling with -xarch=v9 or v9a and running the executable on a SPARC platform running the 64-bit enabled Solaris operating environment) changes the return values of certain functions. These are usually functions that interface standard system-level routines, such as malloc(3F) (see page 76), and may take or return 32-bit or 64-bit values depending on the environment. To provide portability of code between 32-bit and 64-bit environments, 64-bit versions of these routines have been provided that always take and/or return 64-bit values. The following table identifies library routine provided for use in 64-bit environments:
TABLE 1-1 Library Routines for 64-bit Environments
Library Routines

malloc64
Allocate memory and return a pointer page 76

fseeko64
Reposition a large file page 40

ftello64
Determine position of a large file page 40

stat64, fstat64, lstat64
Determine status of a file page 95

time64,
ctime64,
gmtime64,
ltime64
Get system time, convert to character or dissected page 96

qsort64
Sort the elements of an array page 83
Fortran Math Functions

The following functions and subroutines are part of the Fortran math libraries. They are available to all programs compiled with f77 and f95. Some routines are intrinsics and return the same data type (single precision, double precision, or quad precision) as their argument. The rest are non-intrinsics that take a specific data type as an argument and return the same. These non-intrinsics do have to be declared in the routine referencing them.

Many of these routines are "wrappers", Fortran interfaces to routines in the C language library, and as such are non-standard Fortran. They include IEEE recommended support functions, and specialized random number generators. See the Numerical Computation Guide and the man pages libm_single(3F), libm_double(3F), libm_quadruple(3F), for more information about these libraries.

Intrinsic Math Functions

Here is a list of intrinsic math functions. You need not put them in a type statement. These functions take single, double, or quad precision data as arguments and return the same.
sqrt(x)

asin(x)

cosd(x)

log(x)

acos(x)

asind(x)

log10(x)

atan(x)

acosd(x)

exp(x)

atan2(x,y)

atand(x)

x**y

sinh(x)

atan2d(x,y)

sin(x)

cosh(x)

aint(x)

cos(x)

tanh(x)

anint(x)

tan(x)

sind(x)

nint(x)
The functions sind(x), cosd(x), asind(x), acosd(x), atand(x), atan2d(x,y) are not part of the Fortran standard.

Single-Precision Functions

These subprograms are single-precision math functions and subroutines.

In general, the functions below provide access to single-precision math functions that do not correspond to standard Fortran generic intrinsic functions--data types are determined by the usual data typing rules.

These functions need not be explicitly typed with a REAL statement as long as default typing holds. (Variables beginning with "r" are REAL, with "i" are INTEGER.)

For details on these routines, see the C math library man pages (3M). For example, for r_acos(x) see the acos(3M) man page.
TABLE 1-2 Single-Precision Math Functions

r_acos( x )

r_acosd( x )

r_acosh( x )

r_acosp( x )

r_acospi( x )

REAL

REAL

REAL

REAL

REAL

Function

Function

Function

Function

Function

arc cosine

--

arc cosh

--

--

r_atan( x )

r_atand( x )

r_atanh( x )

r_atanp( x )

r_atanpi( x )

REAL

REAL

REAL

REAL

REAL

Function

Function

Function

Function

Function

arc tangent

--

arc tanh

--

--

r_asin( x )

r_asind( x )

r_asinh( x )

r_asinp( x )

r_asinpi( x )

REAL

REAL

REAL

REAL

REAL

Function

Function

Function

Function

Function

arc sine

--

arc sinh

--

--

r_atan2(( y, x )

r_atan2d( y, x )

r_atan2pi( y, x )

REAL

REAL

REAL

Function

Function

Function

arc tangent

--

--

r_cbrt( x )

r_ceil( x )

r_copysign( x, y )

REAL

REAL

REAL

Function

Function

Function

cube root

ceiling

--

r_cos( x )

r_cosd( x )

r_cosh( x )

r_cosp( x )

r_cospi( x )

REAL

REAL

REAL

REAL

REAL

Function

Function

Function

Function

Function

cosine

--

hyperb cos

--

--

r_erf( x )

r_erfc( x )

REAL

REAL

Function

Function

err function

--

r_expm1( x )

r_floor( x )

r_hypot( x, y )

r_infinity( )

REAL

REAL

REAL

REAL

Function

Function

Function

Function

(e**x)-1

floor

hypotenuse

--

r_j0( x )

r_j1( x )

r_jn( x )

REAL

REAL

REAL

Function

Function

Function

Bessel
--

--

ir_finite( x )

ir_fp_class( x )

ir_ilogb( x )

ir_irint( x )

ir_isinf( x )

ir_isnan( x )

ir_isnormal( x )

ir_issubnormal( x )

ir_iszero( x )

ir_signbit( x )

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

Function

Function

Function

Function

Function

Function

Function

Function

Function

Function

--

--

--

--

--

--

--

--

--

--

r_addran()

r_addrans( x, p, l, u )

r_lcran()

r_lcrans( x, p, l, u )

r_shufrans(x, p, l, u)

REAL

n/a

REAL

n/a

n/a

Function

Subroutine

Function

Subroutine

Subroutine

random
number
generators

r_lgamma( x )

r_logb( x )

r_log1p( x )

r_log2( x )

REAL

REAL

REAL

REAL

Function

Function

Function

Function

log gamma

--

--

--

r_max_normal()

r_max_subnormal()

r_min_normal()

r_min_subnormal()

r_nextafter( x, y )

r_quiet_nan( n )

r_remainder( x, y )

r_rint( x )

r_scalb( x, y )

r_scalbn( x, n )

r_signaling_nan( n )

r_significand( x )

REAL

REAL

REAL

REAL

REAL

REAL

REAL

REAL

REAL

REAL

REAL

REAL

Function

Function

Function

Function

Function

Function

Function

Function

Function

Function

Function

Function

r_sin( x )

r_sind( x )

r_sinh( x )

r_sinp( x )

r_sinpi( x )

REAL

REAL

REAL

REAL

REAL

Function

Function

Function

Function

Function

sine

--

hyperb sin

--

--

r_sincos( x, s, c )

r_sincosd( x, s, c )

r_sincosp( x, s, c )

r_sincospi( x, s, c )

n/a

n/a

n/a

n/a

Subroutine

Subroutine

Subroutine

Subroutine

sine & cosine

--

--

--

r_tan( x )

r_tand( x )

r_tanh( x )

r_tanp( x )

r_tanpi( x )

REAL

REAL

REAL

REAL

REAL

Function

Function

Function

Function

Function

tangent

--

hyperb tan

--

--

r_y0( x )

r_y1( x )

r_yn( n, x )

REAL

REAL

REAL

Function

Function

Function

bessel

--

--
Variables c, l, p, s, u, x, and y are of type REAL.
Type these functions as explicitly REAL if an IMPLICIT statement is in effect that types names starting with "r" to some other date type.
sind(x), asind(x), ... take degrees rather than radians.

See also: intro(3M) and the Numerical Computation Guide.

Double-Precision Functions

The following subprograms are double-precision math functions and subroutines.

In general, these functions do not correspond to standard Fortran generic intrinsic functions--data types are determined by the usual data typing rules.

These DOUBLE PRECISION functions need to appear in a DOUBLE PRECISION statement.

Refer to the C library man pages for details: the man page for d_acos(x) is acos(3M)
TABLE 1-3 Double Precision Math Functions

d_acos( x )

d_acosd( x )

d_acosh( x )

d_acosp( x )

d_acospi( x )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

Function

Function

arc cosine

--

arc cosh

--

--

d_atan( x )

d_atand( x )

d_atanh( x )

d_atanp( x )

d_atanpi( x )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

Function

Function

arc tangent

--

arc tanh

--

--

d_asin( x )

d_asind( x )

d_asinh( x )

d_asinp( x )

d_asinpi( x )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

Function

Function

arc sine

--

arc sinh

--

--

d_atan2(( y, x )

d_atan2d( y, x )

d_atan2pi( y, x )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

arc tangent

--

--

d_cbrt( x )

d_ceil( x )

d_copysign( x, x )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

cube root

ceiling

--

d_cos( x )

d_cosd( x )

d_cosh( x )

d_cosp( x )

d_cospi( x )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

Function

Function

cosine

--

hyperb cos

--

--

d_erf( x )

d_erfc( x )

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

error func

--

d_expm1( x )

d_floor( x )

d_hypot( x, y )

d_infinity( )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

Function

(e**x)-1

floor

hypotenuse

--

d_j0( x )

d_j1( x )

d_jn( x )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

Bessel

--

--

id_finite( x )

id_fp_class( x )

id_ilogb( x )

id_irint( x )

id_isinf( x )

id_isnan( x )

id_isnormal( x )

id_issubnormal( x )

id_iszero( x )

id_signbit( x )

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

Function

Function

Function

Function

Function

Function

Function

Function

Function

Function

d_addran()

d_addrans(x, p, l, u)

d_lcran()

d_lcrans(x, p, l, u )

d_shufrans(x, p, l,u)

DOUBLE PRECISION

n/a

DOUBLE PRECISION

n/a

n/a

Function
Subroutin e
Function
Subroutin e
Subroutin e

random
number
generators

d_lgamma( x )

d_logb( x )

d_log1p( x )

d_log2( x )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

Function

log gamma

--

--

--

d_max_normal()

d_max_subnormal()

d_min_normal()

d_min_subnormal()

d_nextafter( x, y )

d_quiet_nan( n )

d_remainder( x, y )

d_rint( x )

d_scalb( x, y )

d_scalbn( x, n )

d_signaling_nan( n )

d_significand( x )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

Function

Function

Function

Function

Function

Function

Function

Function

Function

d_sin( x )

d_sind( x )

d_sinh( x )

d_sinp( x )

d_sinpi( x )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

Function

Function

sine

--

hyper sine

--

--

d_sincos( x, s, c )

d_sincosd( x, s, c )

d_sincosp( x, s, c )

d_sincospi( x, s, c )

n/a

n/a

n/a

n/a

Subroutin e
Subroutin e
Subroutin e
Subroutin e

sine & cosine

--

--

d_tan( x )

d_tand( x )

d_tanh( x )

d_tanp( x )

d_tanpi( x )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

Function

Function

tangent

--

hyperb tan

--

--

d_y0( x )

d_y1( x )

d_yn( n, x )

DOUBLE PRECISION

DOUBLE PRECISION

DOUBLE PRECISION

Function

Function

Function

bessel

--

--
Variables c, l, p, s, u, x, and y are of type DOUBLE PRECISION.
Explicitly type these functions on a DOUBLE PRECISION statement or with an appropriate IMPLICIT statement).
sind(x), asind(x), ... take degrees rather than radians.

See also: intro(3M) and the Numerical Computation Guide.

Quad-Precision Functions

These subprograms are quadruple-precision (REAL*16) math functions and subroutines (SPARC only).

In general, these do not correspond to standard generic intrinsic functions; data types are determined by the usual data typing rules.

The quadruple precision functions must appear in a REAL*16 statement
TABLE 1-4 Quadruple-Precision libm Functions

q_copysign( x, y )

q_fabs( x )

q_fmod( x )

q_infinity( )

REAL*16

REAL*16

REAL*16

REAL*16

Function

Function

Function

Function

iq_finite( x )

iq_fp_class( x )

iq_ilogb( x )

iq_isinf( x )

iq_isnan( x )

iq_isnormal( x )

iq_issubnormal( x )

iq_iszero( x )

iq_signbit( x )

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

INTEGER

Function

Function

Function

Function

Function

Function

Function

Function

Function

q_max_normal()

q_max_subnormal()

q_min_normal()

q_min_subnormal()

q_nextafter( x, y )

q_quiet_nan( n )

q_remainder( x, y )

q_scalbn( x, n )

q_signaling_nan( n )

REAL*16

REAL*16

REAL*16

REAL*16

REAL*16

REAL*16

REAL*16

REAL*16

REAL*16

Function

Function

Function

Function

Function

Function

Function

Function

Function
The variables c, l, p, s, u, x, and y are of type quadruple precision.
Explicitly type these functions with a REAL*16 statement or with an appropriate IMPLICIT statement.
sind(x), asind(x), ... take degrees rather than radians.

If you need to use any other quadruple-precision libm function, you can call it using $PRAGMA C(fcn) before the call. For details, see the chapter on the C-Fortran interface in the Fortran Programming Guide.

abort: Terminate and Write Core File

The subroutine is called by:
call abort
abort flushes the I/O buffers and then aborts the process, possibly producing a core file memory dump in the current directory. See limit(1) about limiting or suppressing core dumps.

access: Check File Permissions or Existence

The function is called by:
INTEGER*4 access status = access ( name, mode )

name
character
Input File name

mode
character
Input Permissions

Return value
INTEGER*4
Output status=0: OK
status>0: Error code
access determines if you can access the file name with the permissions specified by mode. access returns zero if the access specified by mode would be successful. See also gerror(3F) to interpret error codes.

Set mode to one or more of r, w, x, in any order or combination, or blank, where r, w, x have the following meanings:

'r' Test for read permission

'w' Test for write permission

'x' Test for execute permission

' ' Test for existence of the file

Example 1: Test for read/write permission:
INTEGER*4 access, status

status = access ( 'taccess.data', 'rw' )

if ( status .eq. 0 ) write(*,*) "ok"

if ( status .ne. 0 ) write(*,*) 'cannot read/write', status
Example 2: Test for existence:
INTEGER*4 access, status

status = access ( 'taccess.data', ' ' ) ! blank mode

if ( status .eq. 0 ) write(*,*) "file exists"

if ( status .ne. 0 ) write(*,*) 'no such file', status
alarm: Call Subroutine After a Specified Time

The function is called by:
INTEGER*4 alarm n = alarm ( time, sbrtn )

time
INTEGER*4
Input Number of seconds to wait (0=do not call)

sbrtn Routine name Input Subprogram to execute must be listed in an external statement.

Return value
INTEGER*4
Output Time remaining on the last alarm
Example: alarm--wait 9 seconds then call sbrtn:
integer*4 alarm, time / 1 /

common / alarmcom / i

external sbrtn

i = 9

write(*,*) i

nseconds = alarm ( time, sbrtn )

do n = 1,100000 ! Wait until alarm activates sbrtn.

r = n ! (any calculations that take enough time)

x=sqrt(r)

end do

write(*,*) i

end

subroutine sbrtn

common / alarmcom / i

i = 3 ! Do no I/O in this routine.

return

end
See also: alarm(3C), sleep(3F), and signal(3F). Note the following restrictions:

A subroutine cannot pass its own name to alarm.
The alarm routine generates signals that could interfere with any I/O. The called subroutine, sbrtn, must not do any I/O itself.
Calling alarm() from a parallelized or multi-threaded Fortran program may have unpredictable results.

bit: Bit Functions: and, or, ..., bit, setbit, ...

The definitions are:

and( word1, word2 ) Computes bitwise and of its arguments.

or( word1, word2 ) Computes bitwise inclusive or of its arguments.

xor( word1, word2 ) Computes bitwise exclusive or of its arguments.

not( word ) Returns bitwise complement of its argument.

lshift( word, nbits ) Logical left shift with no end around carry.

rshift( word, nbits ) Arithmetic right shift with sign extension.

call bis( bitnum, word ) Sets bit bitnum in word to 1.

call bic( bitnum, word ) Clears bit bitnum in word to 0.

bit( bitnum, word ) Tests bit bitnum in word and returns .true. if the bit is 1, .false. if it is 0.

call setbit(bitnum,word,state) Sets bit bitnum in word to 1 if state is nonzero, and clears it otherwise.

The alternate external versions for MIL-STD-1753 are:
iand( m, n)
Computes the bitwise and of its arguments.

ior( m, n)
Computes the bitwise inclusive or of its arguments.

ieor( m, n)
Computes the bitwise exclusive or of its arguments.

ishft( m, k)
Is a logical shift with no end around carry (left if k>0, right if k<0).

ishftc( m, k, ic)
Circular shift: right-most ic bits of m are left-shifted circularly k places.

ibits( m, i, len)
Extracts bits: from m, starting at bit i, extracts len bits.

ibset( m, i)
Sets bit: return value is equal to word m with bit number i set to 1.

ibclr( m, i)
Clears bit: return value is equal to word m with bit number i set to 0.

btest( m, i)
Tests bit i in m; returns .true. if the bit is 1, and .false. if it is 0.
See also mvbits: Move a Bit Field, and the chapter on Intrinsic Functions in the FORTRAN 77 Reference Manual.

Usage: and, or, xor, not, rshift, lshift

For the intrinsic functions:
x = and( word1, word2)

x = or( word1, word2)

x = xor( word1, word2)

x = not( word)

x = rshift( word, nbits)

x = lshift( word, nbits)
word, word1, word2, nbits are integer input arguments. These are intrinsic functions expanded inline by the compiler. The data type returned is that of the first argument.

No test is made for a reasonable value of nbits.

Example: and, or, xor, not:
demo% cat tandornot.f

print 1, and(7,4), or(7,4), xor(7,4), not(4)

1 format(4x 'and(7,4)', 5x 'or(7,4)', 4x 'xor(7,4)',

& 6x 'not(4)'/4o12.11)

end

demo%f77 -silent tandornot.f

demo% a.out

and(7,4) or(7,4) xor(7,4) not(4)

00000000004 00000000007 00000000003 37777777773

demo%
Example: lshift, rshift:
integer*4 lshift, rshift

print 1, lshift(7,1), rshift(4,1)

1 format(1x 'lshift(7,1)', 1x 'rshift(4,1)'/2o12.11)

end

demo%f77 -silent tlrshift.f

demo% a.out

lshift(7,1) rshift(4,1)

00000000016 00000000002

demo%
Usage: bic, bis, bit, setbit

call bic( bitnum, word)

call bis( bitnum, word)

call setbit( bitnum, word, state)

LOGICAL bit

x = bit( bitnum, word)
bitnum, state, and word are INTEGER*4 input arguments. Function bit() returns a logical value.

Bits are numbered so that bit 0 is the least significant bit, and bit 31 is the most significant.

bic, bis, and setbit are external subroutines. bit is an external function.

Example 3: bic, bis, setbit, bit:
integer*4 bitnum/2/, state/0/, word/7/

logical bit

print 1, word

1 format(13x 'word', o12.11)

call bic( bitnum, word )

print 2, word

2 format('after bic(2,word)', o12.11)

call bis( bitnum, word )

print 3, word

3 format('after bis(2,word)', o12.11)

call setbit( bitnum, word, state )

print 4, word

4 format('after setbit(2,word,0)', o12.11)

print 5, bit(bitnum, word)

5 format('bit(2,word)', L )

end

<output>

word 00000000007

after bic(2,word) 00000000003

after bis(2,word) 00000000007

after setbit(2,word,0) 00000000003

bit(2,word) F
chdir: Change Default Directory

The function is called by:
INTEGER*4 chdir

n = chdir( dirname)

dirname
character
Input Directory name

Return value
INTEGER*4
Output n=0: OK, n>0: Error code
Example: chdir--change cwd to MyDir:
INTEGER*4 chdir, n

n = chdir ( 'MyDir' )

if ( n .ne. 0 ) stop 'chdir: error'

end
See also: chdir(2), cd(1), and gerror(3F) to interpret error codes.

Path names can be no longer than MAXPATHLEN as defined in <sys/param.h>. They can be relative or absolute paths.

Use of this function can cause inquire by unit to fail.

Certain Fortran file operations reopen files by name. Using chdir while doing I/O can cause the runtime system to lose track of files created with relative path names. including the files that are created by open statements without file names.

chmod: Change the Mode of a File

The function is called by:
INTEGER*4 chmod

n = chmod( name, mode)

name
character
Input Path name

mode
character
Input Anything recognized by chmod(1), such as o-w, 444, etc.

Return value
INTEGER*4
Output n = 0: OK; n>0: System error number
Example: chmod--add write permissions to MyFile:
character*18 name, mode

INTEGER*4 chmod, n

name = 'MyFile'

mode = '+w'

n = chmod( name, mode )

if ( n .ne. 0 ) stop 'chmod: error'

end
See also: chmod(1), and gerror(3F) to interpret error codes.

Path names cannot be longer than MAXPATHLEN as defined in <sys/param.h>. They can be relative or absolute paths.

date: Get Current Date as a Character String

Note – This routine is not "Year 2000 Safe" because it returns only a two-digit value for the year. Programs that compute differences between dates using the output of this routine may not work properly after 31 December, 1999. Programs using this date() routine will see a runtime warning message the first time the routine is called to alert the user. See date_and_time() as a possible alternate routine.

The subroutine is called by:
call date( c)

c CHARACTER*9 Output Variable, array, array element, or character substring
The form of the returned string c is dd-mmm-yy, where dd is the day of the month as a 2-digit number, mmm is the month as a 3-letter abbreviation, and yy is the year as a 2-digit number (and is not year 2000 safe!).

Example: date:
demo% cat dat1.f

* dat1.f -- Get the date as a character string.

character c*9

call date ( c )

write(*,"(' The date today is: ', A9 )" ) c

end

demo% f77 -silent dat1.f

"dat.f", line 2: Warning: Subroutine "date" is not safe after
year 2000; use "date_and_time" instead

demo% a.out

Computing time differences using the 2 digit year from subroutine
date is not safe after year 2000.

The date today is: 9-Jul-98

demo%
See also idate() and date_and_time().

date_and_time: Get Date and Time

This is a FORTRAN 77 version of the Fortran 95 intrinsic routine, and is Year 2000 safe.

The date_and_time subroutine returns data from the real-time clock and the date. Local time is returned, as well as the difference between local time and Universal Coordinated Time (UTC) (also known as Greenwich Mean Time, GMT).

The date_and_time() subroutine is called by:
call date_and_time( date, time, zone, values)

date
CHARACTER*8
Output Date, in form CCYYMMDD, where CCYY is the four-digit year, MM the two-digit month, and DD the two-digit day of the month. For example: 19980709

time
CHARACTER*10
Output The current time, in the form hhmmss.sss, where hh is the hour, mm minutes, and ss.sss seconds and milliseconds.

zone
CHARACTER*5
Output The time difference with respect to UTC, expressed in hours and minutes, in the form hhmm

values INTEGER*4 VALUES(8) Output An integer array of 8 elements described below.
The eight values returned in the INTEGER*4 values array are
VALUES(1)
The year, as a 4-digit integer. For example, 1998.

VALUES(2)
The month, as an integer from 1 to 12.

VALUES(3)
The day of the month, as an integer from 1 to 31.

VALUES(4)
The time difference, in minutes, with respect to UTC.

VALUES(5)
The hour of the day, as an integer from 1 to 23.

VALUES(6)
The minutes of the hour, as an integer from 1 to 59.

VALUES(7)
The seconds of the minute, as an integer from 0 to 60.

VALUES(8)
The milliseconds of the second, in range 0 to 999.
An example using date_and_time:
demo% cat dtm.f

integer date_time(8)

character*10 b(3)

call date_and_time(b(1), b(2), b(3), date_time)

print *,'date_time array values:'

print *,'year=',date_time(1)

print *,'month_of_year=',date_time(2)

print *,'day_of_month=',date_time(3)

print *,'time difference in minutes=',date_time(4)

print *,'hour of day=',date_time(5)

print *,'minutes of hour=',date_time(6)

print *,'seconds of minute=',date_time(7)

print *,'milliseconds of second=',date_time(8)

print *, 'DATE=',b(1)

print *, 'TIME=',b(2)

print *, 'ZONE=',b(3)

end
When run on a computer in California, USA on February 16, 2000, it generated the following output:
date_time array values:

year= 2000

month_of_year= 2

day_of_month= 16

time difference in minutes= -420

hour of day= 11

minutes of hour= 49

seconds of minute= 29

milliseconds of second= 236

DATE=20000216

TIME=114929.236

ZONE=-0700
dtime, etime: Elapsed Execution Time

Both functions have return values of elapsed time (or -1.0 as error indicator).
The time returned is in seconds.

The versions of dtime and etime used by Fortran 77 return times produced by the runtime system's high resolution clock. The actual resolution depends on the system platform. The resolutions of the clocks on current platforms range between one nanosecond and one microsecond.

Versions of dtime and etime used by Fortran 95 use the system's low resolution clock by default. The resolution is one hundreth of a second. However, if the program is run under the Sun OS^TM operating system utility ptime(1), (/usr/proc/bin/ptime), the high resolution clock is used.

dtime: Elapsed Time Since the Last dtime Call

For dtime, the elapsed time is:

First call: elapsed time since start of execution
Subsequent calls: elapsed time since the last call to dtime
Single processor: time used by the CPU
Multiple Processor: the sum of times for all the CPUs, which is not useful data; use etime instead.
Note – Calling dtime from within a parallelized loop gives non-deterministic results, since the elapsed time counter is global to all threads participating in the loop

The function is called by:
e = dtime( tarray)

tarray
real(2)
Output e= -1.0: Error: tarray values are undefined e -1.0: User time in tarray(1) if no error. System time in tarray(2) if no error

Return value
real
Output e= -1.0: Error e -1.0: The sum of tarray(1) and tarray(2)
Example: dtime(), single processor:
real e, dtime, t(2)

print *, 'elapsed:', e, ', user:', t(1), ', sys:', t(2)

do i = 1, 10000

k=k+1

end do

e = dtime( t )

print *, 'elapsed:', e, ', user:', t(1), ', sys:', t(2)

end

demo% f77 -silent tdtime.f

demo% a.out

elapsed: 0., user: 0., sys: 0.

elapsed: 0.180000, user: 6.00000E-02, sys: 0.120000

demo%
etime: Elapsed Time Since Start of Execution

For etime, the elapsed time is:

Single Processor--CPU time for the calling process
Multiple Processors--wallclock time while processing your program

Here is how Fortran decides single processor or multiple processor:

For a parallelized Fortran program linked with libF77_mt, if the environment variable PARALLEL is:

Undefined, the current run is single processor.
Defined and in the range 1, 2, 3, ..., the current run is multiple processor.
Defined, but some value other than 1, 2, 3, ..., the results are unpredictable.

The function is called by:
e = etime( tarray)

tarray
real(2)
Output e= -1.0: Error: tarray values are undefined. e -1.0: Single Processor: User time in tarray(1). System time in tarray(2) Multiple Processor: Wall clock time in tarray(1), 0.0 in tarray(2)

Return value
real
Output e= -1.0: Error e -1.0: The sum of tarray(1) and tarray(2)
Take note that the initial call to etime will be inaccurate. It merely enables the system clock. Do not use the value returned by the initial call to etime.

Example: etime(), single processor:
real e, etime, t(2)

e = etime(t) ! Startup etime - do not use result

do i = 1, 10000

k=k+1

end do

e = etime( t )

print *, 'elapsed:', e, ', user:', t(1), `, sys:', t(2)

end

demo% f77 -silent tetime.f

demo% a.out

elapsed: 0.190000, user: 6.00000E-02, sys: 0.130000

demo%
See also times(2), f77(1), and the Fortran Programming Guide.

exit: Terminate a Process and Set the Status

The subroutine is called by:
call exit( status)

status INTEGER*4 Input
Example: exit():
...

if(dx .lt. 0.) call exit( 0 )

...

end
exit flushes and closes all the files in the process, and notifies the parent process if it is executing a wait.

The low-order 8 bits of status are available to the parent process. These 8 bits are shifted left 8 bits, and all other bits are zero. (Therefore, status should be in the range of 256 - 65280). This call will never return.

The C function exit can cause cleanup actions before the final system 'exit'.

Calling exit without an argument causes a compile-time warning message, and a zero will be automatically provided as an argument. See also: exit(2), fork(2), fork(3F), wait(2), wait(3F).

fdate: Return Date and Time in an ASCII String

The subroutine or function is called by:
call fdate( string)

string
character*24
Output
or:
CHARACTER fdate*24 string = fdate() If used as a function, the calling routine must define the type and size of fdate.

Return value
character*24
Output
Example 1: fdate as a subroutine:
character*24 string

call fdate( string )

write(*,*) string

end
Output:
Wed Aug 3 15:30:23 1994
Example 2: fdate as a function, same output:
character*24 fdate

write(*,*) fdate()

end
See also: ctime(3), time(3F), and idate(3F).

flush: Flush Output to a Logical Unit

The function is called by:
INTEGER*4 flush

n = flush( lunit)

lunit
INTEGER*4
Input Logical unit

Return value
INTEGER*4
Output n = 0 no error
n > 0 error number
The flush function flushes the contents of the buffer for the logical unit, lunit, to the associated file. This is most useful for logical units 0 and 6 when they are both associated with the console terminal. The function returns a positive error number if an error was encountered; zero otherwise.

See also fclose(3S).

fork: Create a Copy of the Current Process

The function is called by:
INTEGER*4 fork

n= fork()

Return value
INTEGER*4
Output n>0: n=Process ID of copy n<0, n=System error code
The fork function creates a copy of the calling process. The only distinction between the two processes is that the value returned to one of them, referred to as the parent process, will be the process ID of the copy. The copy is usually referred to as the child process. The value returned to the child process will be zero.

All logical units open for writing are flushed before the fork to avoid duplication of the contents of I/O buffers in the external files.

Example: fork():
INTEGER*4 fork, pid

pid = fork()

if(pid.lt.0) stop 'fork error'

if(pid.gt.0) then

print *, 'I am the parent'

else

print *, 'I am the child'

endif
A corresponding exec routine has not been provided because there is no satisfactory way to retain open logical units across the exec routine. However, the usual function of fork/exec can be performed using system(3F). See also: fork(2), wait(3F), kill(3F), system(3F), and perror(3F).

free: Deallocate Memory Allocated by Malloc

The subroutine is called by:
call free ( ptr)

ptr pointer Input
free deallocates a region of memory previously allocated by malloc. The region of memory is returned to the memory manager; it is no longer available to the user's program.

Example: free():
real x

pointer ( ptr, x )

ptr = malloc ( 10000 )

call free ( ptr )

end
See malloc, malloc64: Allocate Memory and Get Address for details.

fseek, ftell: Determine Position and Reposition a File

fseek and ftell are routines that permit repositioning of a file. ftell returns a file's current position as an offset of so many bytes from the beginning of the file. At some later point in the program, fseek can use this saved offset value to reposition the file to that same place for reading.

fseek: Reposition a File on a Logical Unit

The function is called by:
INTEGER*4 fseek

n = fseek( lunit, offset, from)

lunit
INTEGER*4
Input Open logical unit

offset
INTEGER*4
or
INTEGER*8
Input Offset in bytes relative to position specified by from

An INTEGER*8 offset value is required when compiled for a 64-bit environment, such as Solaris 7, with -xarch=v9. If a literal constant is supplied, it must be a 64-bit constant, for example: 100_8

from
INTEGER*4
Input 0=Beginning of file 1=Current position 2=End of file

Return value
INTEGER*4
Output n=0: OK; n>0: System error code
Note – On sequential files, following a call to fseek by an output operation (for example, WRITE) causes all data records following the fseek position to be deleted and replaced by the new data record (and an end-of-file mark). Rewriting a record in place can only be done with direct access files.

Example: fseek()--Reposition MyFile to two bytes from the beginning
INTEGER*4 fseek, lunit/1/, offset/2/, from/0/, n

open( UNIT=lunit, FILE='MyFile' )

n = fseek( lunit, offset, from )

if ( n .gt. 0 ) stop 'fseek error'

end
:

Example: Same example in a 64-bit environment and compiled with -xarch=v9:
INTEGER*4 fseek, lunit/1/, from/0/, n

INTEGER*8 offset/2/

open( UNIT=lunit, FILE='MyFile' )

n = fseek( lunit, offset, from )

if ( n .gt. 0 ) stop 'fseek error'

end
ftell: Return Current Position of File

The function is called by:
INTEGER*4 ftell

n = ftell( lunit)

lunit
INTEGER*4
Input Open logical unit

Return value INTEGER*4 or INTEGER*8 Output n>=0: n=Offset in bytes from start of file n<0: n=System error code

An INTEGER*8 offset value is returned when compiling for a 64-bit environment, such as Solaris 7, with -xarch=v9. ftell and variables receiving this return value should be declared INTEGER*8.
Example: ftell():
INTEGER*4 ftell, lunit/1/, n

open( UNIT=lunit, FILE='MyFile' )

...

n = ftell( lunit )

if ( n .lt. 0 ) stop 'ftell error'

...
Example: Same example in a 64-bit environment and compiled with -xarch=v9:
INTEGER*4 lunit/1/

INTEGER*8 ftell, n

open( UNIT=lunit, FILE='MyFile' )

...

n = ftell( lunit )

if ( n .lt. 0 ) stop 'ftell error'

...
See also fseek(3S) and perror(3F); also fseeko64(3F) ftello64(3F).

fseeko64, ftello64: Determine Position and Reposition a Large File

fseeko64 and ftello64 are "large file" versions of fseek and ftell. They take and return INTEGER*8 file position offsets on Solaris 2.6 and Solaris 7. (A "large file" is larger than 2 Gigabytes and therefore a byte-position must be represented by a 64-bit integer.) Use these versions to determine and/or reposition large files.

fseeko64: Reposition a File on a Logical Unit

The function is called by:
INTEGER fseeko64

n = fseeko64( lunit, offset64, from)

lunit
INTEGER*4
Input Open logical unit

offset64
INTEGER*8
Input 64-bit offset in bytes relative to position specified by from

from
INTEGER*4
Input 0=Beginning of file 1=Current position 2=End of file

Return value
INTEGER*4
Output n=0: OK; n>0: System error code
Note – On sequential files, following a call to fseeko64 by an output operation (for example, WRITE) causes all data records following the fseek position to be deleted and replaced by the new data record (and an end-of-file mark). Rewriting a record in place can only be done with direct access files.

Example: fseeko64()--Reposition MyFile to two bytes from the beginning:
INTEGER fseeko64, lunit/1/, from/0/, n

INTEGER*8 offset/200/

open( UNIT=lunit, FILE='MyFile' )

n = fseeko64( lunit, offset, from )

if ( n .gt. 0 ) stop 'fseek error'

end
ftello64: Return Current Position of File

The function is called by:
INTEGER*8 ftello64

n = ftello64( lunit)

lunit
INTEGER*4
Input Open logical unit

Return value
INTEGER*8
Output n0: n=Offset in bytes from start of file n<0: n=System error code
Example: ftello64():
INTEGER*8 ftello64, lunit/1/, n

open( UNIT=lunit, FILE='MyFile' )

...

n = ftello64( lunit )

if ( n .lt. 0 ) stop 'ftell error'

...
getarg, iargc: Get Command-Line Arguments

getarg and iargc access arguments on the command line (after expansion by the command-line preprocessor.

getarg: Get a Command-Line Argument

The subroutine is called by:
call getarg( k, arg)

k
INTEGER*4
Input Index of argument (0=first=command name)

arg character*n Output kth argument

n
INTEGER*4
Size of arg Large enough to hold longest argument
iargc: Get the Number of Command-Line Arguments

The function is called by:
m= iargc()

Return value
INTEGER*4
Output Number of arguments on the command line
Example: iargc and getarg, get argument count and each argument:
demo% cat yarg.f

character argv*10

INTEGER*4 i, iargc, n

n = iargc()

do 1 i = 1, n

call getarg( i, argv )

1 write( *, '( i2, 1x, a )' ) i, argv

end

demo% f77 -silent yarg.f

demo% a.out *.f

1 first.f

2 yarg.f
See also execve(2) and getenv(3F).

getc, fgetc: Get Next Character

getc and fgetc get the next character from the input stream.Do not mix calls to these routines with normal Fortran I/O on the same logical unit.

getc: Get Next Character from stdin

The function is called by:
INTEGER*4 getc

status = getc( char)

char
character
Output Next character

Return value
INTEGER*4
Output status=0: OK status=-1: End of file status>0: System error code or
f77 I/O error code
Example: getc gets each character from the keyboard; note the Control-D (^D):
character char

INTEGER*4 getc, status

status = 0

do while ( status .eq. 0 )

status = getc( char )

write(*, '(i3, o4.3)') status, char

end do

end
After compiling, a sample run of the above source is:
demo% a.out

ab Program reads letters typed in

^D terminated by a CONTROL-D.

0 141 Program outputs status and octal value of the characters entered

0 142 141 represents 'a', 142 is 'b'

0 012 012 represents the RETURN key

-1 012 Next attempt to read returns CONTROL-D

demo%
For any logical unit, do not mix normal Fortran input with getc().

fgetc: Get Next Character from Specified Logical Unit

The function is called by:
INTEGER*4 fgetc

status = fgetc( lunit, char)

lunit
INTEGER*4
Input Logical unit

char
character
Output Next character

Return value
INTEGER*4
Output status=-1: End of File status>0: System error code or f77 I/O error code
Example: fgetc gets each character from tfgetc.data; note the linefeeds (Octal 012):
character char

INTEGER*4 fgetc, status

open( unit=1, file='tfgetc.data' )

status = 0

do while ( status .eq. 0 )

status = fgetc( 1, char )

write(*, '(i3, o4.3)') status, char

end do

end
After compiling, a sample run of the above source is:
demo% cat tfgetc.data

ab

yz

demo% a.out

0 141 `a' read

0 142 `b' read

0 012 linefeed read

0 171 `y' read

0 172 `z' read

0 012 linefeed read

-1 012 CONTROL-D read

demo%
For any logical unit, do not mix normal Fortran input with fgetc().

See also: getc(3S), intro(2), and perror(3F).

getcwd: Get Path of Current Working Directory

The function is called by:
INTEGER*4 getcwd

status = getcwd( dirname)

dirname character*n Output The path of the current directory is returned Path name of the current working directory. n must be large enough for longest path name

Return value
INTEGER*4
Output status=0: OK status>0: Error code
Example: getcwd:
INTEGER*4 getcwd, status

character*64 dirname

status = getcwd( dirname )

if ( status .ne. 0 ) stop 'getcwd: error'

write(*,*) dirname

end
See also: chdir(3F), perror(3F), and getwd(3).

Note: the path names cannot be longer than MAXPATHLEN as defined in <sys/param.h>.

getenv: Get Value of Environment Variables

The subroutine is called by:
call getenv( ename, evalue)

ename character*n Input Name of the environment variable sought

evalue character*n Output Value of the environment variable found; blanks if not successful
The size of ename and evalue must be large enough to hold their respective character strings.

The getenv subroutine searches the environment list for a string of the form ename=evalue and returns the value in evalue if such a string is present; otherwise, it fills evalue with blanks.

Example: Use getenv() to print the value of $SHELL:
character*18 evalue

call getenv( 'SHELL', evalue )

write(*,*) "'", evalue, "'"

end
See also: execve(2) and environ(5).

getfd: Get File Descriptor for External Unit Number

The function is called by:
INTEGER*4 getfd

fildes = getfd( unitn)

unitn
INTEGER*4
Input External unit number

Return value INTEGER*4-or-
INTEGER*8 Output File descriptor if file is connected;
-1 if file is not connected
An INTEGER*8 result is returned when compiling for 64-bit environments
Example: getfd():
INTEGER*4 fildes, getfd, unitn/1/

open( unitn, file='tgetfd.data' )

fildes = getfd( unitn )

if ( fildes .eq. -1 ) stop 'getfd: file not connected'

write(*,*) 'file descriptor = ', fildes

end
See also open(2).

getfilep: Get File Pointer for External Unit Number

The function is:
irtn = c_read( getfilep( unitn ), inbyte, 1 )

c_read C function Input User's own C function. See example.

unitn
INTEGER*4
Input External unit number.

getfilep

INTEGER*4-or-
INTEGER*8
Return value File pointer if the file is connected; -1 if the file is not connected.
An INTEGER*8 value is returned when compiling for 64-bit environments
This function is used for mixing standard Fortran I/O with C I/O. Such a mix is nonportable, and is not guaranteed for subsequent releases of the operating system or Fortran. Use of this function is not recommended, and no direct interface is provided. You must create your own C routine to use the value returned by getfilep. A sample C routine is shown below.

Example: Fortran uses getfilep by passing it to a C function:
tgetfilepF.f:

character*1 inbyte

integer*4 c_read, getfilep, unitn / 5 /

external getfilep

write(*,'(a,$)') 'What is the digit? '

irtn = c_read( getfilep( unitn ), inbyte, 1 )

write(*,9) inbyte

9 format('The digit read by C is ', a )

end
Sample C function actually using getfilep:
tgetfilepC.c:

#include <stdio.h>

int c_read_ ( fd, buf, nbytes, buf_len )

FILE **fd ;

char *buf ;

int *nbytes, buf_len ;

{

return fread( buf, 1, *nbytes, *fd ) ;

}
A sample compile-build-run is:
demo 11% cc -c tgetfilepC.c

demo 12% f77 tgetfilepC.o tgetfilepF.f

tgetfileF.f:

MAIN:

demo 13% a.out

What is the digit? 3

The digit read by C is 3

demo 14%
For more information, read the chapter on the C-Fortran interface in the Fortran Programming Guide. See also open(2).

getlog: Get User's Login Name

The subroutine is called by:
call getlog( name)

name
character*n
Output User's login name, or all blanks if the process is running detached from a terminal. n should be large enough to hold the longest name.
Example: getlog:
character*18 name

call getlog( name )

write(*,*) "'", name, "'"

end
See also getlogin(3).

getpid: Get Process ID

The function is called by:
INTEGER*4 getpid

pid= getpid()

Return value
INTEGER*4
Output Process ID of the current process
Example: getpid:
INTEGER*4 getpid, pid

pid = getpid()

write(*,*) 'process id = ', pid

end
See also getpid(2).

getuid, getgid: Get User or Group ID of Process

getuid and getgid get the user or group ID of the process, respectively.

getuid: Get User ID of the Process

The function is called by:
INTEGER*4 getuid

uid = getuid()

Return value
INTEGER*4
Output User ID of the process
getgid: Get Group ID of the Process

The function is called by:
INTEGER*4 getgid

gid = getgid()

Return value
INTEGER*4
Output Group ID of the process
Example: getuid() and getpid():
INTEGER*4 getuid, getgid, gid, uid

uid = getuid()

gid = getgid()

write(*,*) uid, gid

end
See also: getuid(2).

hostnm: Get Name of Current Host

The function is called by:
INTEGER*4 hostnm

status = hostnm( name)

name character*n Output Name of current host system. n must be large enough to hold the host name.

Return value
INTEGER*4
Output status=0: OK status>0: Error
Example: hostnm():
INTEGER*4 hostnm, status

character*8 name

status = hostnm( name )

write(*,*) 'host name = "', name, '"'

end
See also gethostname(2).

idate: Return Current Date

idate has two versions:

Standard--Put the current system date into an integer array: day, month, and year.
VMS--Put the current system date into three integer variables: month, day, and year. This version is not "Year 2000 Safe".

The -lV77 compiler option request the VMS library and links the VMS versions of both time() and idate(); otherwise, the linker accesses the standard versions. (VMS versions of library routines are only available with f77 through the -lV77 library option, and not with f95).

The standard version puts the current system date into one integer array: day, month, and year.

The subroutine is called by:
call idate( iarray ) Standard Version

iarray
INTEGER*4
Output Three-element array: day, month, year.
Example: idate (standard version):
demo% cat tidate.f

INTEGER*4 iarray(3)

call idate( iarray )

write(*, "(' The date is: ',3i5)" ) iarray

end

demo% f77 -silent tidate.f

demo% a.out

The date is: 10 8 1998

demo%
The VMS idate() subroutine is called by:
call idate( m, d, y ) VMS Version

m
INTEGER*4
Output Month (1 - 12)

d
INTEGER*4
Output Day (1 - 7)

y
INTEGER*4
Output Year (1 - 99) Not year 2000 safe!
Using the VMS idate() routine will cause a warning message at link time and the first time the routine is called in execution.

Note – The VMS version of the idate() routine is not "Year 2000 Safe" because it returns only a two-digit value for the year. Programs that compute differences between dates using the output of this routine may not work properly after 31 December, 1999. Programs using this idate() routine will see a runtime warning message the first time the routine is called to alert the user. See date_and_time() as a possible alternate.

Example: idate (VMS version):
demo% cat titime.f

INTEGER*4 m, d, y

call idate ( m, d, y )

write (*, "(' The date is: ',3i5)" ) m, d, y

end

demo% f77 -silent tidateV.f -lV77

"titime.f", line 2: Warning: Subroutine "idate" is not safe after

year 2000; use "date_and_time" instead

demo% a.out

Computing time differences using the 2 digit year from subroutine

idate is not safe after year 2000.

The date is: 7 10 98
ieee_flags,ieee_handler, sigfpe: IEEE Arithmetic

These subprograms provide modes and status required to fully exploit ANSI/IEEE Standard 754-1985 arithmetic in a Fortran program. They correspond closely to the functions ieee_flags(3M), ieee_handler(3M), and sigfpe(3).

Here is a summary:
TABLE 1-5 IEEE Arithmetic Support Routines

ieeer = ieee_flags( action,mode,in,out)

ieeer = ieee_handler(action,exception,hdl)

ieeer = sigfpe( code, hdl)

action
character
Input

code
sigfpe_code_type
Input

mode
character
Input

in
character
Input

exception
character
Input

hdl
sigfpe_handler_type
Input

out
character
Output

Return value
INTEGER*4
Output
See the Sun Numerical Computation Guide for details on how these functions can be used strategically.

If you use sigfpe, you must do your own setting of the corresponding trap-enable-mask bits in the floating-point status register. The details are in the SPARC architecture manual. The libm function ieee_handler sets these trap-enable-mask bits for you.

The character keywords accepted for mode and exception depend on the value of action.
TABLE 1-6   ieee_flags(action,mode,in,out) Parameters and Actions

action = 'clearall'
mode, in, out, unused; returns 0

action = 'clear' clear mode, in out is unused; returns 0
mode = 'direction'

mode = 'precision' (on x86 platforms only)

mode = 'exception'

in = 'inexact'       or

'division'     or

'underflow'    or

'overflow'    or

'invalid'    or

'all'    or

'common'

action = 'set' set floating-point mode,in out is unused; returns 0
mode = 'direction'

in = 'nearest'       or

'tozero'       or

'positive'     or

'negative'

mode = 'precision'
(on x86 only)

in = 'extended'     or

'double'       or

'single'

mode = 'exception'

in = 'inexact'       or

'division'     or

'underflow'    or

'overflow'    or

'invalid'    or

'all'    or

'common'

action = 'get' test mode settings in, out may be blank or one of the settings to test returns the current setting depending on mode, or 'not available'
The function returns 0 or the current exception flags if mode = 'exception'
mode = 'direction'

out = 'nearest'       or

'tozero'       or

'positive'     or

'negative'

mode = 'precision'
(on x86 only)

out = 'extended'     or

'double'       or

'single'

mode = 'exception'

out = 'inexact'       or

'division'     or

'underflow'    or

'overflow'    or

'invalid'    or

'all'    or

'common'
TABLE 1-7   ieee_handler(action,in,out) Parameters
action = 'clear' clear user exception handing of in; out is unused
in = 'inexact'       or

'division'     or

'underflow'    or

'overflow'    or

'invalid'    or

'all'    or

'common'

action = 'set' set user exception handing of in; out is address of handler routine, or SIGFPE_DEFAULT, or SIGFPE_ABORT, or SIGFPE_IGNORE defined in f77/f77_floating point.h
in = 'inexact'       or

'division'     or

'underflow'    or

'overflow'    or

'invalid'    or

'all'    or

'common'

Example 1: Set rounding direction to round toward zero, unless the hardware does not support directed rounding modes:
INTEGER*4 ieeer

character*1 mode, out, in

ieeer = ieee_flags( 'set', 'direction', 'tozero', out )
Example 2: Clear rounding direction to default (round toward nearest):
character*1 out, in

ieeer = ieee_flags('clear','direction', in, out )
Example 3: Clear all accrued exception-occurred bits:
character*18 out

ieeer = ieee_flags( 'clear', 'exception', 'all', out )
Example 4: Detect overflow exception as follows:
character*18 out

ieeer = ieee_flags( 'get', 'exception', 'overflow', out )

if (out .eq. 'overflow' ) stop 'overflow'
The above code sets out to overflow and ieeer to 25 (this value is platform dependent). Similar coding detects exceptions, such as invalid or inexact.

Example 5: hand1.f, write and use a signal handler (f77):
external hand

real r / 14.2 /, s / 0.0 /

i = ieee_handler( 'set', 'division', hand )

t = r/s

end

INTEGER*4 function hand ( sig, sip, uap )

INTEGER*4 sig, address

structure /fault/

INTEGER*4 address

end structure

structure /siginfo/

INTEGER*4 si_signo

INTEGER*4 si_code

INTEGER*4 si_errno

record /fault/ fault

end structure

record /siginfo/ sip

address = sip.fault.address

write (*,10) address

10 format('Exception at hex address ', z8 )

end
Change the declarations for address and function hand to INTEGER*8 to enable Example 5 in a 64-bit, SPARC V9 environment (-xarch=v9)

See the Numerical Computation Guide. See also: floatingpoint(3), signal(3), sigfpe(3), f77_floatingpoint(3F), ieee_flags(3M), and ieee_handler(3M).

f77_floatingpoint.h: Fortran IEEE Definitions

The header file f77_floatingpoint.h defines constants and types used to implement standard floating-point according to ANSI/IEEE Std 754-1985.

Include the file in a FORTRAN 77 source program as follows:
#include "f77_floatingpoint.h"
Use of this include file requires preprocessing prior to Fortran compilation. The source file referencing this include file will automatically be preprocessed if the name has a .F, .F90 or .F95 extension.

Fortran 95 programs should include the file floatingpoint.h instead.

IEEE Rounding Mode:
fp_direction_type
The type of the IEEE rounding direction mode. The order of enumeration varies according to hardware.
SIGFPE Handling:
sigfpe_code_type
The type of a SIGFPE code.

sigfpe_handler_type
The type of a user-definable SIGFPE exception handler called to handle a particular SIGFPE code.

SIGFPE_DEFAULT
A macro indicating default SIGFPE exception handling: IEEE exceptions to continue with a default result and to abort for other SIGFPE codes.

SIGFPE_IGNORE
A macro indicating an alternate SIGFPE exception handling, namely to ignore and continue execution.

SIGFPE_ABORT
A macro indicating an alternate SIGFPE exception handling, namely to abort with a core dump.
IEEE Exception Handling:
N_IEEE_EXCEPTION
The number of distinct IEEE floating-point exceptions.

fp_exception_type
The type of the N_IEEE_EXCEPTION exceptions. Each exception is given a bit number.

fp_exception_field_type
The type intended to hold at least N_IEEE_EXCEPTION bits corresponding to the IEEE exceptions numbered by fp_exception_type. Thus, fp_inexact corresponds to the least significant bit and fp_invalid to the fifth least significant bit. Some operations can set more than one exception.
IEEE Classification:
fp_class_type
A list of the classes of IEEE floating-point values and symbols.
Refer to the Numerical Computation Guide. See also ieee_environment(3M) and f77_ieee_environment(3F).

index,rindex,lnblnk: Index or Length of Substring

These functions search through a character string:
index(a1,a2)
Index of first occurrence of string a2 in string a1

rindex(a1,a2)
Index of last occurrence of string a2 in string a1

lnblnk(a1)
Index of last nonblank in string a1
index has the following forms:

index: First Occurrence of a Substring in a String

The index is an intrinsic function called by:
n = index( a1, a2)

a1
character
Input Main string

a2
character
Input Substring

Return value
INTEGER
Output n>0: Index of first occurrence of a2 in a1 n=0: a2 does not occur in a1.
If declared INTEGER*8, index() will return an INTEGER*8 value when compiled for a 64-bit environment and character variable a1 is a very large character string (greater than 2 Gigabytes).

rindex: Last Occurrence of a Substring in a String

The function is called by:
INTEGER*4 rindex

n = rindex( a1, a2)

a1
character
Input Main string

a2
character
Input Substring

Return value
INTEGER*4or
INTEGER*8
Output n>0: Index of last occurrence of a2 in a1 n=0: a2 does not occur in a1
INTEGER*8 returned in 64-bit environments
lnblnk: Last Nonblank in a String

The function is called by:
n = lnblnk( a1)

a1
character
Input String

Return value
INTEGER*4or
INTEGER*8
Output n>0: Index of last nonblank in a1 n=0: a1 is all nonblank
INTEGER*8 returned in 64-bit environments
Example: index(), rindex(), lnblnk():
* 123456789012345678901

character s*24 / 'abcPDQxyz...abcPDQxyz' /

INTEGER*4 declen, index, first, last, len, lnblnk, rindex

declen = len( s )

first = index( s, 'abc' )

last = rindex( s, 'abc' )

lastnb = lnblnk( s )

write(*,*) declen, lastnb

write(*,*) first, last

end

demo% f77 -silent tindex.f

demo% a.out

24 21 <- declen is 24 because intrinsic len() returns the declared length of s

1 13
Note – Programs compiled to run in a 64-bit environment must declare index, rindex and lnblnk (and their receiving variables) INTEGER*8 to handle very large character strings.

inmax: Return Maximum Positive Integer

The function is called by:
m= inmax()

Return value
INTEGER*4
Output The maximum positive integer
Example: inmax:
INTEGER*4 inmax, m

m = inmax()

write(*,*) m

end

demo% f77 -silent tinmax.f

demo% a.out

2147483647

demo%
See also libm_single(3F) and libm_double(3F). See also the intrinsic function ephuge() described in the FORTRAN 77 Language Reference Manual.

ioinit: Initialize I/O Properties

The IOINIT routine (FORTRAN 77 only) establishes properties of file I/O for files opened after the call to IOINIT. The file I/O properties that IOINIT controls are as follows:

Carriage control: Recognize carriage control on any logical unit.
Blanks/zeroes: Treat blanks in input data fields as blanks or zeroes.
File position: Open files at beginning or at end-of-file.
Prefix: Find and open files named prefixNN, 0 NN 19.

IOINIT does the following:

Initializes global parameters specifying f77 file I/O properties
Opens logical units 0 through 19 with the specified file I/O properties--attaches externally defined files to logical units at runtime

Persistence of File I/O Properties

The file I/O properties apply as long as the connection exists. If you close the unit, the properties no longer apply. The exception is the preassigned units 5 and 6, to which carriage control and blanks/zeroes apply at any time.

Internal Flags

IOINIT uses labeled common to communicate with the runtime I/O system. It stores internal flags in the equivalent of the following labeled common block:
INTEGER*2 IEOF, ICTL, IBZR

COMMON /__IOIFLG/ IEOF, ICTL, IBZR ! Not in user name space
In earlier releases (prior to 3.0.1) the labeled common block was named IOIFLG. The name changed subsequently to __IOIFLG to prevent conflicts with any user-defined common blocks.

Source Code

Some user needs are not satisfied with a generic version of IOINIT, so we provide the source code. It is written in Fortran 77. The location is:

<install>/SUNWspro/<release>/src/ioinit.f

where <install> is usually /opt for a standard installation of the Sun WorkShop software packages, and <release> path changes with every release of the compilers.

Usage: ioinit

The ioinit subroutine is called by:
call ioinit ( cctl, bzro, apnd, prefix, vrbose)

cctl
logical
Input True: Recognize carriage control, all formatted output (except unit 0)

bzro
logical
Input True: Treat trailing and imbedded blanks as zeroes.

apnd
logical
Input True: Open files at EoF. Append.

prefix
character*n
Input Nonblank: For unit NN, seek and open file prefixNN

vrbose
logical
Input True: Report ioinit activity as it happens
See also getarg(3F) and getenv(3F).

Restrictions

Note the following restrictions:

prefix can be no longer than 30 characters.
A path name associated with an environment name can be no longer than 255 characters.

Description of Arguments

These are the arguments for ioinit.

cctl (Carriage Control)

By default, carriage control is not recognized on any logical unit. If cctl is .TRUE., then carriage control is recognized on formatted output to all logical units, except unit 0, the diagnostic channel. Otherwise, the default is restored.

bzro (Blanks)

By default, trailing and embedded blanks in input data fields are ignored. If bzro is .TRUE., then such blanks are treated as zeros. Otherwise, the default is restored.

apnd (Append)

By default, all files opened for sequential access are positioned at their beginning. It is sometimes necessary or convenient to open at the end-of-file, so that a write will append to the existing data. If apnd is .TRUE., then files opened subsequently on any logical unit are positioned at their end upon opening. A value of .FALSE. restores the default behavior.

prefix (Automatic File Connection)

If the argument prefix is a nonblank string, then names of the form prefixNN are sought in the program environment. The value associated with each such name found is used to open the logical unit NN for formatted sequential access.

This search and connection is provided only for NN between 0 and 19, inclusive. For NN > 19, nothing is done; see Source Code.

vrbose (IOINIT Activity)

If the argument vrbose is .TRUE., then IOINIT reports on its own activity.

Example: The program myprogram has the following ioinit call:
call ioinit( .true., .false., .false., 'FORT', .false.)
You can assign file name in at least two ways.

In sh:
demo$ FORT01=mydata

demo$ FORT12=myresults

demo$ export FORT01 FORT12

demo$ myprogram
In csh:
demo% setenv FORT01 mydata

demo% setenv FORT12 myresults

demo% myprogram
With either shell, the ioinit call in the above example gives these results:

Open logical unit 1 to the file, mydata.
Open logical unit 12 to the file, myresults.
Both files are positioned at their beginning.
Any formatted output has column 1 removed and interpreted as carriage control.
Embedded and trailing blanks are to be ignored on input.

Example: ioinit()--list and compile:
demo% cat tioinit.f

character*3 s

call ioinit( .true., .false., .false., 'FORT', .false.)

do i = 1, 2

read( 1, '(a3,i4)') s, n

write( 12, 10 ) s, n

end do

10 format(a3,i4)

end

demo% cat tioinit.data

abc 123

PDQ 789

demo% f77 -silent tioinit.f

demo%
You can set environment variables as follows, using either sh or csh:

ioinit()--sh:
demo$ FORT01=tioinit.data

demo$ FORT12=tioinit.au

demo$ export FORT01 FORT12

demo$
ioinit()--csh:
demo% setenv FORT01 tioinit.data

demo% setenv FORT12 tioinit.au
ioinit()--Run and test:
demo% a.out

demo% cat tioinit.au

abc 123

PDQ 789
itime: Current Time

itime puts the current system time into an integer array: hour, minute, and second. The subroutine is called by:
call itime( iarray)

iarray
INTEGER*4
Output 3-element array: iarray(1) = hour iarray(2) = minute iarray(3) = second
Example: itime:
demo% cat titime.f

INTEGER*4 iarray(3)

call itime( iarray )

write (*, "(' The time is: ',3i5)" ) iarray

end

demo% f77 -silent titime.f

demo%a.out

The time is: 15 42 35
See also time(3F), ctime(3F), and fdate(3F).

kill: Send a Signal to a Process

The function is called by:
status = kill( pid, signum)

pid
INTEGER*4
Input Process ID of one of the user's processes

signum
INTEGER*4
Input Valid signal number. See signal(3).

Return value
INTEGER*4
Output status=0: OK status>0: Error code
Example (fragment): Send a message using kill():
INTEGER*4 kill, pid, signum

* ...

status = kill( pid, signum )

if ( status .ne. 0 ) stop 'kill: error'

write(*,*) 'Sent signal ', signum, ' to process ', pid

end
The function sends signal signum, and integer signal number, to the process pid. Valid signal numbers are listed in the C include file /usr/include/sys/signal.h

See also: kill(2), signal(3), signal(3F), fork(3F), and perror(3F).

link, symlnk: Make a Link to an Existing File

link creates a link to an existing file. symlink creates a symbolic link to an existing file.

The functions are called by:
status = link( name1, name2)

INTEGER*4 symlnk
status = symlnk( name1, name2 )

name1 character*n Input Path name of an existing file

name2 character*n Input Path name to be linked to the file, name1. name2 must not already exist.

Return value
INTEGER*4
Output status=0: OK status>0: System error code
link: Create a Link to an Existing File

Example 1: link: Create a link named data1 to the file, tlink.db.data.1:
demo% cat tlink.f

character*34 name1/'tlink.db.data.1'/, name2/'data1'/

integer*4 link, status

status = link( name1, name2 )

if ( status .ne. 0 ) stop 'link: error'

end

demo%f77 -silent tlink.f

demo% ls -l data1

data1 not found

demo% a.out

demo% ls -l data1

-rw-rw-r-- 2 generic 2 Aug 11 08:50 data1

demo%
symlnk: Create a Symbolic Link to an Existing File

Example 2: symlnk: Create a symbolic link named data1 to the file, tlink.db.data.1:
demo% cat tsymlnk.f

character*34 name1/'tlink.db.data.1'/, name2/'data1'/

INTEGER*4 status, symlnk

status = symlnk( name1, name2 )

if ( status .ne. 0 ) stop 'symlnk: error'

end

demo% f77 -silent tsymlnk.f

demo% ls -l data1

data1 not found

demo% a.out

demo% ls -l data1

lrwxrwxrwx 1 generic 15 Aug 11 11:09 data1 -> tlink.db.data.1

demo%
See also: link(2), symlink(2), perror(3F), and unlink(3F).

Note: the path names cannot be longer than MAXPATHLEN as defined in <sys/param.h>.

loc: Return the Address of an Object

This intrinsic function is called by:
k = loc( arg)

arg Any type Input Variable or array

Return value
INTEGER*4-or- INTEGER*8 Output Address of arg

Returns an INTEGER*8 pointer when compiled to run in a 64-bit environment with -xarch=v9. See Note below.
Example: loc:
INTEGER*4 k, loc

real arg / 9.0 /

k = loc( arg )

write(*,*) k

end
Note – Programs compiled to run in a 64-bit environment should declare INTEGER*8 the variable receiving output from the loc() function.

long, short: Integer Object Conversion

long and short handle integer object conversions between INTEGER*4 and INTEGER*2, and is especially useful in subprogram call lists.

long: Convert a Short Integer to a Long Integer

The function is called by:
call ExpecLong( long(int2) )

int2
INTEGER*2
Input

Return value
INTEGER*4
Output
short: Convert a Long Integer to a Short Integer

The function is:
INTEGER*2 short

call ExpecShort( short(int4) )

int4
INTEGER*4
Input

Return value
INTEGER*2
Output
Example (fragment): long() and short():
integer*4 int4/8/, long

integer*2 int2/8/, short

call ExpecLong( long(int2) )

call ExpecShort( short(int4) )

...

end
ExpecLong is some subroutine called by the user program that expects a long (INTEGER*4) integer argument. Similarly, ExpecShort expects a short (INTEGER*2) integer argument.

long is useful if constants are used in calls to library routines and the code is compiled with the -i2 option.

short is useful in similar context when an otherwise long object must be passed as a short integer. Passing an integer to short that is too large in magnitude does not cause an error, but will result in unexpected behavior.

longjmp, isetjmp: Return to Location Set by isetjmp

isetjmp sets a location for longjmp; longjmp returns to that location.

isetjmp: Set the Location for longjmp

This intrinsic function is called by:
ival = isetjmp( env)

env
INTEGER*4
Output env is a 12-element integer array.
In 64-bit environments it must be declared INTEGER*8

Return value
INTEGER*4
Output ival = 0 if isetjmp is called explicitly ival 0 if isetjmp is called through longjmp
longjmp: Return to the Location Set by isetjmp

The subroutine is called by:
call longjmp( env, ival)

env
INTEGER*4
Input env is the 12-word integer array initialized by isetjmp.
In 64-bit environments it must be declared INTEGER*8

ival
INTEGER*4
Output ival = 0 if isetjmp is called explicitly ival 0 if isetjmp is called through longjmp
Description

The isetjmp and longjmp routines are used to deal with errors and interrupts encountered in a low-level routine of a program. They are f77 intrinsics.

These routines should be used only as a last resort. They require discipline, and are not portable. Read the man page, setjmp (3V), for bugs and other details.

isetjmp saves the stack environment in env. It also saves the register environment.

longjmp restores the environment saved by the last call to isetjmp, and returns in such a way that execution continues as if the call to isetjmp had just returned the value ival.

The integer expression ival returned from isetjmp is zero if longjmp is not called, and nonzero if longjmp is called.

Example: Code fragment using isetjmp and longjmp:
INTEGER*4 env(12)

common /jmpblk/ env

j = isetjmp( env )

if ( j .eq. 0 ) then
call sbrtnA
else

call error_processor

end if

end

subroutine sbrtnA

INTEGER*4 env(12)

common /jmpblk/ env

call longjmp( env, ival )

return

end
Restrictions

You must invoke isetjmp before calling longjmp.
The env integer array argument to isetjmp and longjmp must be at least 12 elements long.
You must pass the env variable from the routine that calls isetjmp to the routine that calls longjmp, either by common or as an argument.
longjmp attempts to clean up the stack. longjmp must be called from a lower call-level than isetjmp.
Passing isetjmp as an argument that is a procedure name does not work.

See setjmp(3V).

malloc, malloc64: Allocate Memory and Get Address

The malloc() function is called by:
k = malloc( n)

n
INTEGER*4
Input Number of bytes of memory

Return value
INTEGER*4 or INTEGER*8
Output k>0: k=address of the start of the block of memory allocated k=0: Error

An INTEGER*8 pointer value is returned when compiled for a 64-bit environment with -xarch=v9. See Note below.
Note – Programs compiled to run on 64-bit environments such as Solaris 7 must declare the malloc() function and the variables receiving its output as INTEGER*8. Portability issues can be solved by using malloc64() instead of malloc() in programs that must run in both 32-bit or 64-bit environments.

The function malloc64(3F) is provided to make programs portable between 32-bit and 64-bit environments:
k = malloc64( n)

n
INTEGER*8
Input Number of bytes of memory

Return value
INTEGER*8
Output k>0: k=address of the start of the block of memory allocated k=0: Error
These functions allocate an area of memory and return the address of the start of that area. (In a 64-bit environment, this returned byte address may be outside the INTEGER*4 numerical range--the receiving variables must be declared INTEGER*8 to avoid truncation of the memory address.) The region of memory is not initialized in any way, and it should not be assumed to be preset to anything, especially zero!

Example: Code fragment using malloc():
parameter (NX=1000)

pointer ( p1, X )

real*4 X(NX)

...

p1 = malloc( NX*4 )

if ( p1 .eq. 0 ) stop 'malloc: cannot allocate'

do 11 i=1,NX

11 X(i) = 0.

...

end
In the above example, we acquire 4,000 bytes of memory, pointed to by p1, and initialize it to zero.

See also free: Deallocate Memory Allocated by Malloc.

mvbits: Move a Bit Field

The subroutine is called by:
call mvbits( src, ini1, nbits, des, ini2)

src
INTEGER*4
Input Source

ini1
INTEGER*4
Input Initial bit position in the source

nbits
INTEGER*4
Input Number of bits to move

des
INTEGER*4
Output Destination

ini2
INTEGER*4
Input Initial bit position in the destination
Example: mvbits:
demo% cat mvb1.f

* mvb1.f -- From src, initial bit 0, move 3 bits to des, initial bit 3.

* src des

* 543210 543210 Bit numbers

* 000111 000001 Values before move

* 000111 111001 Values after move

INTEGER*4 src, ini1, nbits, des, ini2

data src, ini1, nbits, des, ini2

& / 7, 0, 3, 1, 3 /

call mvbits ( src, ini1, nbits, des, ini2 )

write (*,"(5o3)") src, ini1, nbits, des, ini2

end

demo% f77 -silent mvb1.f

demo% a.out

7 0 3 71 3

demo%
Note the following:

Bits are numbered 0 to 31, from least significant to most significant.
mvbits changes only bits ini2 through ini2+nbits-1 of the des location, and no bits of the src location.
The restrictions are:

ini1 + nbits 32
ini2 + nbits 32

perror, gerror, ierrno: Get System Error Messages

These routines perform the following functions:
perror Print a message to Fortran logical unit 0, stderr.

gerror
Get a system error message (of the last detected system error)

ierrno
Get the error number of the last detected system error.
perror: Print Message to Logical Unit 0, stderr

The subroutine is called by:
call perror( string)

string
character*n
Input The message. It is written preceding the standard error message for the last detected system error.
Example 1:
call perror( "file is for formatted I/O" )
gerror: Get Message for Last Detected System Error

The subroutine or function is called by:
call gerror( string)

string
character*n
Output Message for the last detected system error
Example 2: gerror() as a subroutine:
character string*30

...

call gerror ( string )

write(*,*) string
Example 3: gerror() as a function; string not used:
character gerror*30, z*30

...

z = gerror( )

write(*,*) z
ierrno: Get Number for Last Detected System Error

The function is called by:
n= ierrno()

Return value
INTEGER*4
Output Number of last detected system error
This number is updated only when an error actually occurs. Most routines and I/O statements that might generate such errors return an error code after the call; that value is a more reliable indicator of what caused the error condition.

Example 4: ierrno():
INTEGER*4 ierrno, n

...

n = ierrno()

write(*,*) n
See also intro(2) and perror(3).

Note:

string in the call to perror cannot be longer than 127 characters.
The length of the string returned by gerror is determined by the calling program.
Runtime I/O error codes for f77 and f95 are listed in the Fortran User's Guide.

putc, fputc: Write a Character to a Logical Unit

putc writes to logical unit 6, normally the control terminal output.

fputc writes to a logical unit.

These functions write a character to the file associated with a Fortran logical unit bypassing normal Fortran I/O.

Do not mix normal Fortran output with output by these functions on the same unit.

putc: Write to Logical Unit 6

The function is called by:
INTEGER*4 putc

status = putc( char)

char
character
Input The character to write to the unit

Return value
INTEGER*4
Output status=0: OK status>0: System error code
Example: putc():
character char, s*10 / 'OK by putc' /

INTEGER*4 putc, status

do i = 1, 10

char = s(i:i)

status = putc( char )

end do

status = putc( '\n' )

end

demo% f77 -silent tputc.f

demo% a.out

OK by putc

demo%
fputc: Write to Specified Logical Unit

The function is called by:
INTEGER*4 fputc

status = fputc( lunit,char)

lunit
INTEGER*4
Input The unit to write to

char
character
Input The character to write to the unit

Return value
INTEGER*4
Output status=0: OK status>0: System error code
Example: fputc():
character char, s*11 / 'OK by fputc' /

INTEGER*4 fputc, status

open( 1, file='tfputc.data')

do i = 1, 11

char = s(i:i)

status = fputc( 1, char )

end do

status = fputc( 1, '\n' )

end

demo% f77 -silent tfputc.f

demo% a.out

demo% cat tfputc.data

OK by fputc

demo%
See also putc(3S), intro(2), and perror(3F).

qsort,qsort64: Sort the Elements of a One-Dimensional Array

The subroutine is called by:
call qsort( array, len, isize, compar )

call qsort64( array, len8, isize8, compar)

array
array
Input Contains the elements to be sorted

len
INTEGER*4
Input Number of elements in the array.

len8
INTEGER*8
Input Number of elements in the array

isize
INTEGER*4
Input Size of an element, typically: 4 for integer or real 8 for double precision or complex 16 for double complex Length of character object for character arrays

isize8
INTEGER*8
Input Size of an element, typically: 4_8 for integer or real 8_8 for double precision or complex 16_8 for double complex Length of character object for character arrays

compar function name Input Name of a user-supplied INTEGER*2 function. Determines sorting order: compar(arg1,arg2)
Use qsort64 in 64-bit environments with arrays larger than 2 Gbytes. Be sure to specify the array length, len8, and the element size, isize8, as INTEGER*8 data. Use the Fortran 95 style constants to explicitly specify INTEGER*8 constants.

The compar(arg1,arg2) arguments are elements of array, returning:

Negative If arg1 is considered to precede arg2

Zero If arg1 is equivalent to arg2

Positive If arg1 is considered to follow arg2

For example:
demo% cat tqsort.f

external compar

integer*2 compar

INTEGER*4 array(10)/5,1,9,0,8,7,3,4,6,2/, len/10/, isize/4/

call qsort( array, len, isize, compar )

write(*,'(10i3)') array

end

integer*2 function compar( a, b )

INTEGER*4 a, b

if ( a .lt. b ) compar = -1

if ( a .eq. b ) compar = 0

if ( a .gt. b ) compar = 1

return

end

demo% f77 -silent tqsort.f

demo% a.out

0 1 2 3 4 5 6 7 8 9
ran: Generate a Random Number Between 0 and 1

Repeated calls to ran generate a sequence of random numbers with a uniform distribution.
r = ran( i )

i
INTEGER*4
Input Variable or array element

r
REAL
Output Variable or array element
See lcrans(3m).

Example: ran:
demo% cat ran1.f

* ran1.f -- Generate random numbers.

INTEGER*4 i, n

real r(10)

i = 760013

do n = 1, 10

r(n) = ran ( i )

end do

write ( *, "( 5 f11.6 )" ) r

end

demo% f77 -silent ran1.f

demo% a.out

0.222058 0.299851 0.390777 0.607055 0.653188

0.060174 0.149466 0.444353 0.002982 0.976519

demo%
Note the following:
The range includes 0.0 and excludes 1.0.
The algorithm is a multiplicative, congruential type, general random number generator.
In general, the value of i is set once during execution of the calling program.
The initial value of i should be a large odd integer.
Each call to RAN gets the next random number in the sequence.
To get a different sequence of random numbers each time you run the program, you must set the argument to a different initial value for each run.
The argument is used by RAN to store a value for the calculation of the next random number according to the following algorithm:

SEED = 6909 * SEED + 1 (MOD 2**32)
SEED contains a 32-bit number, and the high-order 24 bits are converted to floating point, and that value is returned.
rand, drand, irand: Return Random Values

rand returns real values in the range 0.0 through 1.0.

drand returns double precision values in the range 0.0 through 1.0.

irand returns positive integers in the range 0 through 2147483647.

These functions use random(3) to generate sequences of random numbers. The three functions share the same 256 byte state array. The only advantage of these functions is that they are widely available on UNIX systems. For better random number generators, compare lcrans, addrans, and shufrans. See also random(3), and the Numerical Computation Guide
i = irand( k )

r = rand( k )

d = drand( k )

k
INTEGER*4
Input k=0: Get next random number in the sequence k=1: Restart sequence, return first number k>0: Use as a seed for new sequence, return first number

rand

REAL*4
Output

drand

REAL*8
Output

irand

INTEGER*4
Output
Example: irand():
integer*4 v(5), iflag/0/

do i = 1, 5

v(i) = irand( iflag )

end do

write(*,*) v

end

demo% f77 -silent trand.f

demo% a.out

2078917053 143302914 1027100827 1953210302 755253631

demo%
rename: Rename a File

The function is called by:
INTEGER*4 rename

status = rename( from, to )

from
character*n
Input Path name of an existing file

to
character*n
Input New path name for the file

Return value
INTEGER*4
Output status=0: OK status>0: System error code
If the file specified by to exists, then both from and to must be the same type of file, and must reside on the same file system. If to exists, it is removed first.

Example: rename()--Rename file trename.old to trename.new
demo% cat trename.f

INTEGER*4 rename, status

character*18 from/'trename.old'/, to/'trename.new'/

status = rename( from, to )

if ( status .ne. 0 ) stop 'rename: error'

end

demo% f77 -silent trename.f

demo% ls trename*

trename.f trename.old

demo% a.out

demo% ls trename*

trename.f trename.new

demo%
See also rename(2) and perror(3F).

Note: the path names cannot be longer than MAXPATHLEN as defined in <sys/param.h>.
secnds: Get System Time in Seconds, Minus Argument

t = secnds( t0)

t0
REAL
Input Constant, variable, or array element

Return Value
REAL
Output Number of seconds since midnight, minus t0
Example: secnds:
demo% cat sec1.f

real elapsed, t0, t1, x, y

t0 = 0.0

t1 = secnds( t0 )

y = 0.1

do i = 1, 10000

x = asin( y )

end do

elapsed = secnds( t1 )

write ( *, 1 ) elapsed

1 format ( ' 10000 arcsines: ', f12.6, ' sec' )

end

demo% f77 -silent sec1.f

demo% a.out

10000 arcsines: 0.009064 sec

demo%
Note that:

The returned value from SECNDS is accurate to 0.01 second.
The value is the system time, as the number of seconds from midnight, and it correctly spans midnight.
Some precision may be lost for small time intervals near the end of the day.

sh: Fast Execution of an sh Command

The function is called by:
INTEGER*4 sh

status = sh( string)

string
character*n
Input String containing command to do

Return value
INTEGER*4
Output Exit status of the shell executed. See wait(2) for an explanation of this value.
Example: sh():
character*18 string / 'ls > MyOwnFile.names' /

INTEGER*4 status, sh

status = sh( string )

if ( status .ne. 0 ) stop 'sh: error'

...

end
The function sh passes string to the sh shell as input, as if the string had been typed as a command.

The current process waits until the command terminates.

The forked process flushes all open files:

For output files, the buffer is flushed to the actual file.
For input files, the position of the pointer is unpredictable.

The sh() function is not MT-safe. Do not call it from multithreaded or parallelized programs.

See also: execve(2), wait(2), and system(3).

Note: string cannot be longer than 1,024 characters.

signal: Change the Action for a Signal

The function is called by:
INTEGER*4 signal or INTEGER*8 signal n = signal( signum, proc, flag )

signum
INTEGER*4
Input Signal number; see signal(3)

proc Routine name Input Name of user signal handling routine; must be in an external statement

flag
INTEGER*4
Input flag < 0: Use proc as the signal handler flag 0: Ignore proc; pass flag as the action: flag = 0: Use the default action flag = 1: Ignore this signal

Return value
INTEGER*4
Output n=-1: System error n>0: Definition of previous action n>1: n=Address of routine that would have been called n<-1: If signum is a valid signal number, then: n=address of routine that would have been called. If signum is a not a valid signal number, then: n is an error number.

INTEGER*8
On 64-bit environments, signal and the variables receiving its output must be declared INTEGER*8
If proc is called, it is passed the signal number as an integer argument.

If a process incurs a signal, the default action is usually to clean up and abort. A signal handling routine provides the capability of catching specific exceptions or interrupts for special processing.

The returned value can be used in subsequent calls to signal to restore a previous action definition.

You can get a negative return value even though there is no error. In fact, if you pass a valid signal number to signal(), and you get a return value less than -1, then it is OK.

f77 arranges to trap certain signals when a process is started. The only way to restore the default f77 action is to save the returned value from the first call to signal.

f77_floatingpoint.h defines proc values SIGFPE_DEFAULT, SIGFPE_IGNORE, and SIGFPE_ABORT. See page 59. (Use floatingpoint.h with f95).

In 64-bit environments, signal must be declared INTEGER*8, along with the variables receiving its output, to avoid truncation of the address that may be returned.

See also kill(1), signal(3), and kill(3F), and Numerical Computation Guide.

sleep: Suspend Execution for an Interval

The subroutine is called by:
call sleep( itime)

itime
INTEGER*4
Input Number of seconds to sleep
The actual time can be up to 1 second less than itime due to granularity in system timekeeping.

Example: sleep():
INTEGER*4 time / 5 /

write(*,*) 'Start'

call sleep( time )

write(*,*) 'End'

end
See also sleep(3).

stat, lstat, fstat: Get File Status

These functions return the following information:

device,
inode number,
protection,
number of hard links,
user ID,
group ID,
device type,
size,
access time,
modify time,
status change time,
optimal blocksize,
blocks allocated

Both stat and lstat query by file name. fstat queries by logical unit.

stat: Get Status for File, by File Name

The function is called by:
INTEGER*4 stat
ierr = stat ( name, statb )

name
character*n
Input Name of the file

statb
INTEGER*4
Output Status structure for the file, 13-element array

Return value
INTEGER*4
Output ierr=0: OK ierr>0: Error code
Example 1: stat():
character name*18 /'MyFile'/

INTEGER*4 ierr, stat, lunit/1/, statb(13)

open( unit=lunit, file=name )

ierr = stat ( name, statb )

if ( ierr .ne. 0 ) stop 'stat: error'

write(*,*)'UID of owner = ',statb(5),', blocks = ',statb(13)

end
fstat: Get Status for File, by Logical Unit

The function
INTEGER*4 fstat
ierr = fstat ( lunit, statb )

lunit
INTEGER*4
Input Logical unit number

statb
INTEGER*4
Output Status for the file: 13-element array

Return value
INTEGER*4
Output ierr=0: OK ierr>0: Error code
is called by:

Example 2: fstat():
character name*18 /'MyFile'/

INTEGER*4 fstat, lunit/1/, statb(13)

open( unit=lunit, file=name )

ierr = fstat ( lunit, statb )

if ( ierr .ne. 0 ) stop 'fstat: error'

write(*,*)'UID of owner = ',statb(5),', blocks = ',statb(13)

end
lstat: Get Status for File, by File Name

The function is called by:
ierr = lstat ( name, statb)

name
character*n
Input File name

statb
INTEGER*4
Output Status array of file, 13 elements

Return value
INTEGER*4
Output ierr=0: OK ierr>0: Error code
Example 3: lstat():
character name*18 /'MyFile'/

INTEGER*4 lstat, lunit/1/, statb(13)

open( unit=lunit, file=name )

ierr = lstat ( name, statb )

if ( ierr .ne. 0 ) stop 'lstat: error'

write(*,*)'UID of owner = ',statb(5),', blocks = ',statb(13)

end
Detail of Status Array for Files

The meaning of the information returned in the INTEGER*4 array statb is as described for the structure stat under stat(2).

Spare values are not included. The order is shown in the following table:

statb(1)
statb(2)
statb(3)
statb(4)
statb(5)
statb(6)
statb(7)
statb(8)
statb(9)
statb(10)
statb(11)
statb(12)
statb(13) Device inode resides on
This inode's number
Protection
Number of hard links to the file
User ID of owner
Group ID of owner
Device type, for inode that is device
Total size of file
File last access time
File last modify time
File last status change time
Optimal blocksize for file system I/O ops
Actual number of blocks allocated

See also stat(2), access(3F), perror(3F), and time(3F).

Note: the path names can be no longer than MAXPATHLEN as defined in <sys/param.h>.

stat64, lstat64, fstat64: Get File Status

64-bit "long file" versions of stat, lstat, fstat. These routines are identical to the non-64-bit routines, except that the 13-element array statb must be declared INTEGER*8.

system: Execute a System Command

The function is called by:
INTEGER*4 system

status = system( string)

string
character*n
Input String containing command to do

Return value
INTEGER*4
Output Exit status of the shell executed. See wait(2) for an explanation of this value.
Example: system():
character*8 string / 'ls s*' /

INTEGER*4 status, system

status = system( string )

if ( status .ne. 0 ) stop 'system: error'

end
The function system passes string to your shell as input, as if the string had been typed as a command. Note: string cannot be longer than 1024 characters.

If system can find the environment variable SHELL, then system uses the value of SHELL as the command interpreter (shell); otherwise, it uses sh(1).

The current process waits until the command terminates.

Historically, cc and f77 developed with different assumptions:

If cc calls system, the shell is always the Bourne shell.
If f77 calls system, then which shell is called depends on the environment variable SHELL.

The system function flushes all open files:

For output files, the buffer is flushed to the actual file.
For input files, the position of the pointer is unpredictable.

See also: execve(2), wait(2), and system(3).

The system() function is not MT-safe. Do not call it from multithreaded or parallelized programs.

time, ctime, ltime, gmtime: Get System Time

These routines have the following functions:
time
Standard version: Get system time as integer (seconds since 0 GMT 1/1/70) VMS Version: Get the system time as character (hh:mm:ss)

ctime
Convert a system time to an ASCII string.

ltime
Dissect a system time into month, day, and so forth, local time.

gmtime
Dissect a system time into month, day, and so forth, GMT.
time: Get System Time

For time(), there are two versions, a standard version and a VMS version. If you use the f77 command-line option -lV77, then you get the VMS version for time() and for idate(); otherwise, you get the standard versions. (The VMS versions of certain library routines is only available with f77 through the -lV77 library option, and not with f95.)

The standard function is called by:
INTEGER*4 time or INTEGER*8

n = time() Standard Version

Return value
INTEGER*4
Output Time, in seconds, since 0:0:0, GMT, 1/1/70

INTEGER*8
Output In 64-bit environments, time returns an INTEGER*8 value
The function time() returns an integer with the time since 00:00:00 GMT,
January 1, 1970, measured in seconds. This is the value of the operating system clock.

Example: time(), version standard with the operating system:
INTEGER*4 n, time

n = time()

write(*,*) 'Seconds since 0 1/1/70 GMT = ', n

end

demo%f77 -silent ttime.f

demo% a.out

Seconds since 0 1/1/70 GMT = 913240205

demo%
The VMS version of time is a subroutine that gets the current system time as a character string.

The VMS subroutine is called by:
call time( t ) VMS Version

t
character*8
Output Time, in the form hh:mm:ss
hh, mm, and ss are each two digits: hh is the hour; mm is the minute; ss is the second
Example: time(t), VMS version, ctime--convert the system time to ASCII:
character t*8

call time( t )

write(*, "(' The current time is ', A8 )") t

end

demo%f77 -silent ttimeV.f -lV77

demo% a.out

The current time is 08:14:13

demo%
ctime: Convert System Time to Character

The function ctime converts a system time, stime, and returns it as a 24-character ASCII string.

The function is called by:
CHARACTER ctime*24

string = ctime( stime)

stime
INTEGER*4
Input System time from time() (standard version)

Return value
character*24
Output System time as character string. Declare ctime and string as character*24.
The format of the ctime returned value is shown in the following example. It is described in the man page ctime(3C).

Example: ctime():
character*24 ctime, string

INTEGER*4 n, time

n = time()

string = ctime( n )

write(*,*) 'ctime: ', string

end

demo% f77 -silent tctime.f

demo% a.out

ctime: Wed Dec 9 13:50:05 1998

demo%
ltime: Split System Time to Month, Day,... (Local)

This routine dissects a system time into month, day, and so forth, for the local time zone.

The subroutine is called by:
call ltime( stime, tarray)

stime
INTEGER*4
Input System time from time() (standard version)

tarray
INTEGER*4(9)
Output System time, local, as day, month, year, ...
For the meaning of the elements in tarray, see the next section.

Example: ltime():
integer*4 stime, tarray(9), time

stime = time()

call ltime( stime, tarray )

write(*,*) 'ltime: ', tarray

end

demo% f77 -silent tltime.f

demo% a.out

ltime: 25 49 10 12 7 91 1 223 1

demo%
gmtime: Split System Time to Month, Day, ... (GMT)

This routine dissects a system time into month, day, and so on, for GMT.

The subroutine is:
call gmtime( stime, tarray)

stime
INTEGER*4
Input System time from time() (standard version)

tarray
INTEGER*4(9)
Output System time, GMT, as day, month, year, ...
Example: gmtime:
integer*4 stime, tarray(9), time

stime = time()

call gmtime( stime, tarray )

write(*,*) 'gmtime: ', tarray

end

demo% f77 -silent tgmtime.f

demo% a.out

gmtime: 12 44 19 18 5 94 6 168 0

demo%
Here are the tarray() values for ltime and gmtime: index, units, and range:

1
2
3
4
5 Seconds (0 - 61)
Minutes (0 - 59)
Hours (0 - 23)
Day of month (1 - 31)
Months since January (0 - 11) 6
7
8
9 Year - 1900
Day of week (Sunday = 0)
Day of year (0 - 365)
Daylight Saving Time,
1 if DST in effect

These values are defined by the C library routine ctime(3C), which explains why the system may return a count of seconds greater than 59. See also: idate(3F), and fdate(3F).

ctime64, gmtime64, ltime64: System Time Routines for 64-bit Environments

These are versions of the corresponding routines ctime, gmtime, and ltime, to provide portability on 64-bit environments. They are identical to these routines except that the input variable stime must be INTEGER*8.

When used in a 32-bit environment with an INTEGER*8 stime, if the value of stime is beyond the INTEGER*4 range ctime64 returns all asterisks, while gmtime and ltime fill the tarray array with -1.

topen, tclose, tread,..., tstate: Tape I/O

(FORTRAN 77 Only) These routines provide an alternative way to manipulate magnetic tape:
topen
Associate a device name with a tape logical unit.

tclose
Write EOF, close tape device channel, and remove association with tlu.

tread
Read next physical record from tape into buffer.

twrite
Write the next physical record from buffer to tape.

trewin
Rewind the tape to the beginning of the first data file.

tskipf
Skip forward over files and/or records, and reset EOF status.

tstate
Determine the logical state of the tape I/O channel.
On any one unit, do not mix these functions with standard Fortran I/O.

You must first use topen() to open a tape logical unit, tlu, for the specified device. Then you do all other operations on the specified tlu. tlu has no relationship at all to any normal Fortran logical unit.

Before you use one of these functions, its name must be in an INTEGER*4 type statement.

topen: Associate a Device with a Tape Logical Unit

The function is called by:
INTEGER*4 topen

n = topen( tlu, devnam, islabeled)

tlu
INTEGER*4
Input Tape logical unit, in the range 0 to 7.

devnam
CHARACTER
Input Device name; for example: '/dev/rst0'

islabeled
LOGICAL
Input True=the tape is labeled A label is the first file on the tape.

Return value
INTEGER*4
Output n=0: OK n<0: Error
This function does not move the tape. See perror(3F) for details.

Example: topen()--open a 1/4-inch tape file:
CHARACTER devnam*9 / '/dev/rst0' /

INTEGER*4 n / 0 /, tlu / 1 /, topen

LOGICAL islabeled / .false. /

n = topen( tlu, devnam, islabeled )

IF ( n .LT. 0 ) STOP "topen: cannot open"

WRITE(*,'("topen ok:", 2I3, 1X, A10)') n, tlu, devnam

END
The output is:
topen ok: 0 1 /dev/rst0
tclose: Write EOF, Close Tape Channel, Disconnect tlu

The function is called by:
INTEGER*4 tclose

n = tclose ( tlu)

tlu
INTEGER*4
Input Tape logical unit, in range 0 to 7

n
INTEGER*4
Return value n=0: OK n<0: Error
Caution – tclose() places an EOF marker immediately after the current location of the unit pointer, and then closes the unit. So if you trewin() a unit before you tclose() it, its contents are discarded.

Example: tclose()--close an opened 1/4-inch tape file:
CHARACTER devnam*9 / '/dev/rst0' /

INTEGER*4 n / 0 /, tlu / 1 /, tclose, topen

LOGICAL islabeled / .false. /

n = topen( tlu, devnam, islabeled )

n = tclose( tlu )

IF ( n .LT. 0 ) STOP "tclose: cannot close"

WRITE(*, '("tclose ok:", 2I3, 1X, A10)') n, tlu, devnam

END
The output is:
tclose ok: 0 1 /dev/rst0
twrite: Write Next Physical Record to Tape

The function is called by:
INTEGER*4 twrite

n = twrite( tlu, buffer)

tlu
INTEGER*4
Input Tape logical unit, in range 0 to 7

buffer
character
Input Must be sized at a multiple of 512

n
INTEGER*4
Return value n>0: OK, and n = the number of bytes written n=0: End of Tape n<0: Error
The physical record length is the size of buffer.

Example: twrite()--write a 2-record file:
CHARACTER devnam*9 / '/dev/rst0' /, rec1*512 / "abcd" /,

& rec2*512 / "wxyz" /

INTEGER*4 n / 0 /, tlu / 1 /, tclose, topen, twrite

LOGICAL islabeled / .false. /

n = topen( tlu, devnam, islabeled )

IF ( n .LT. 0 ) STOP "topen: cannot open"

n = twrite( tlu, rec1 )

IF ( n .LT. 0 ) STOP "twrite: cannot write 1"

n = twrite( tlu, rec2 )

IF ( n .LT. 0 ) STOP "twrite: cannot write 2"

WRITE(*, '("twrite ok:", 2I4, 1X, A10)') n, tlu, devnam

END
The output is:
twrite ok: 512 1 /dev/rst0
tread: Read Next Physical Record from Tape

The function is called by:
INTEGER*4 tread

n = tread( tlu, buffer)

tlu
INTEGER*4
Input Tape logical unit, in range 0 to 7.

buffer
character
Input Must be sized at a multiple of 512, and must be large enough to hold the largest physical record to be read.

n
INTEGER*4
Return value n>0: OK, and n is the number of bytes read. n<0: Error n=0: EOF
If the tape is at EOF or EOT, then tread does a return; it does not read tapes.

Example: tread()--read the first record of the file written above:
CHARACTER devnam*9 / '/dev/rst0' /, onerec*512 / " " /

INTEGER*4 n / 0 /, tlu / 1 /, topen, tread

LOGICAL islabeled / .false. /

n = topen( tlu, devnam, islabeled )

IF ( n .LT. 0 ) STOP "topen: cannot open"

n = tread( tlu, onerec )

IF ( n .LT. 0 ) STOP "tread: cannot read"

WRITE(*,'("tread ok:", 2I4, 1X, A10)') n, tlu, devnam

WRITE(*,'( A4)') onerec

END
The output is:
tread ok: 512 1 /dev/rst0

abcd
trewin: Rewind Tape to Beginning of First Data File

The function is called by:
INTEGER*4 trewin

n = trewin ( tlu)

tlu
INTEGER*4
Input Tape logical unit, in range 0 to 7

n
INTEGER*4
Return value n=0: OK n<0: Error
If the tape is labeled, then the label is skipped over after rewinding.

Example 1: trewin()--typical fragment:
CHARACTER devnam*9 / '/dev/rst0' /

INTEGER*4 n /0/, tlu /1/, tclose, topen, tread, trewin

...

n = trewin( tlu )

IF ( n .LT. 0 ) STOP "trewin: cannot rewind"

WRITE(*, '("trewin ok:", 2I4, 1X, A10)') n, tlu, devnam

...

END
Example 2: trewin()--in a two-record file, try to read three records, rewind, read one record:
CHARACTER devnam*9 / '/dev/rst0' /, onerec*512 / " " /

INTEGER*4 n / 0 /, r, tlu / 1 /, topen, tread, trewin

LOGICAL islabeled / .false. /

n = topen( tlu, devnam, islabeled )

IF ( n .LT. 0 ) STOP "topen: cannot open"

DO r = 1, 3

n = tread( tlu, onerec )

WRITE(*,'(1X, I2, 1X, A4)') r, onerec

END DO

n = trewin( tlu )

IF ( n .LT. 0 ) STOP "trewin: cannot rewind"

WRITE(*, '("trewin ok:" 2I4, 1X, A10)') n, tlu, devnam

n = tread( tlu, onerec )

IF ( n .LT. 0 ) STOP "tread: cannot read after rewind"

WRITE(*,'(A4)') onerec

END
The output is:
1 abcd

2 wxyz

3 wxyz

trewin ok: 0 1 /dev/rst0

abcd
tskipf: Skip Files and Records; Reset EoF Status

The function is called by:
INTEGER*4 tskipf

n = tskipf( tlu, nf, nr)

tlu
INTEGER*4
Input Tape logical unit, in range 0 to 7

nf
INTEGER*4
Input Number of end-of-file marks to skip over first

nr
INTEGER*4
Input Number of physical records to skip over after skipping files

n
INTEGER*4
Return value n=0: OK n<0: Error
This function does not skip backward.

First, the function skips forward over nf end-of-file marks. Then, it skips forward over nr physical records. If the current file is at EOF, this counts as one file to skip. This function also resets the EOF status.

Example: tskipf()--typical fragment: skip four files and then skip one record:
INTEGER*4 nfiles / 4 /, nrecords / 1 /, tskipf, tlu / 1 /

...

n = tskipf( tlu, nfiles, nrecords )

IF ( n .LT. 0 ) STOP "tskipf: cannot skip"

...
Compare with tstate() .

tstate: Get Logical State of Tape I/O Channel

The function is called by:
INTEGER*4 tstate

n = tstate( tlu, fileno, recno, errf, eoff, eotf, tcsr)

tlu
INTEGER*4
Input Tape logical unit, in range 0 to 7

fileno
INTEGER*4
Output Current file number

recno
INTEGER*4
Output Current record number

errf
LOGICAL
Output True=an error occurred

eoff
LOGICAL
Output True=the current file is at EOF

eotf
LOGICAL
Output True=tape has reached logical end-of-tape

tcsr
INTEGER*4
Output True=hardware errors on the device. It contains the tape drive control status register. If the error is software, then tcsr is returned as zero. The values returned in this status register vary grossly with the brand and size of tape drive.
For details, see st(4s).

While eoff is true, you cannot read from that tlu. You can set this EOF status flag to false by using tskipf() to skip one file and zero records:
n = tskipf( tlu, 1, 0).
Then you can read any valid record that follows.

End-of-tape (EOT) is indicated by an empty file, often referred to as a double EOF mark. You cannot read past EOT, but you can write past it.

Example: Write three files of two records each:
CHARACTER devnam*10 / '/dev/nrst0' /,

& f0rec1*512 / "eins" /, f0rec2*512 / "zwei" /,

& f1rec1*512 / "ichi" /, f1rec2*512 / "ni__" /,

& f2rec1*512 / "un__" /, f2rec2*512 / "deux" /

INTEGER*4 n / 0 /, tlu / 1 /, tclose, topen, trewin, twrite

LOGICAL islabeled / .false. /

n = topen( tlu, devnam, islabeled )

n = trewin( tlu )

n = twrite( tlu, f0rec1 )

n = twrite( tlu, f0rec2 )

n = tclose( tlu )

n = topen( tlu, devnam, islabeled )

n = twrite( tlu, f1rec1 )

n = twrite( tlu, f1rec2 )

n = tclose( tlu )

n = topen( tlu, devnam, islabeled )

n = twrite( tlu, f2rec1 )

n = twrite( tlu, f2rec2 )

n = tclose( tlu )

END
The next example uses tstate() to trap EOF and get at all files.

Example: Use tstate() in a loop that reads all records of the 3 files written in the previous example:
CHARACTER devnam*10 / '/dev/nrst0' /, onerec*512 / " " /

INTEGER*4 f, n / 0 /, tlu / 1 /, tcsr, topen, tread,

& trewin, tskipf, tstate

LOGICAL errf, eoff, eotf, islabeled / .false. /

n = topen( tlu, devnam, islabeled )

n = tstate( tlu, fn, rn, errf, eoff, eotf, tcsr )

WRITE(*,1) 'open:', fn, rn, errf, eoff, eotf, tcsr

1 FORMAT(1X, A10, 2I2, 1X, 1L, 1X, 1L,1X, 1L, 1X, I2 )

2 FORMAT(1X, A10,1X,A4,1X,2I2,1X,1L,1X,1L,1X,1L,1X,I2)

n = trewin( tlu )

n = tstate( tlu, fn, rn, errf, eoff, eotf, tcsr )

WRITE(*,1) 'rewind:', fn, rn, errf, eoff, eotf, tcsr

DO f = 1, 3

eoff = .false.

DO WHILE ( .NOT. eoff )

n = tread( tlu, onerec )

n = tstate( tlu, fn, rn, errf, eoff, eotf, tcsr )

IF (.NOT. eoff) WRITE(*,2) 'read:', onerec,

& fn, rn, errf, eoff, eotf, tcsr

END DO

n = tskipf( tlu, 1, 0 )

n = tstate( tlu, fn, rn, errf, eoff, eotf, tcsr )

WRITE(*,1) 'tskip: ', fn, rn, errf, eoff, eotf, tcsr

END DO

END
The output is:
open: 0 0 F F F 0

rewind: 0 0 F F F 0

read: eins 0 1 F F F 0

read: zwei 0 2 F F F 0

tskip: 1 0 F F F 0

read: ichi 1 1 F F F 0

read: ni__ 1 2 F F F 0

tskip: 2 0 F F F 0

read: un__ 2 1 F F F 0

read: deux 2 2 F F F 0

tskip: 3 0 F F F 0
A summary of EOF and EOT follows:

If you are at either EOF or EOT, then:

Any tread() just returns; it does not read the tape.
A successful tskipf(tlu,1,0) resets the EOF status to false, and returns; it does not advance the tape pointer.

A successful twrite() resets the EOF and EOT status flags to false.
A successful tclose() resets all those flags to false.
tclose() truncates; it places an EOF marker immediately after the current location of the unit pointer, and then closes the unit. So, if you use trewin() to rewind a unit before you use tclose() to close it, its contents are discarded. This behavior of tclose() is inherited from the Berkeley code.

See also: ioctl(2), mtio(4s), perror(3F), read(2), st(4s), and write(2).

ttynam, isatty: Get Name of a Terminal Port

ttynam and isatty handle terminal port names.

ttynam: Get Name of a Terminal Port

The function ttynam returns a blank padded path name of the terminal device associated with logical unit lunit.

The function is called by:
CHARACTER ttynam*24

name = ttynam( lunit)

lunit
INTEGER*4
Input Logical unit

Return value
character*n
Output If nonblank returned: name=path name of device on lunit. Size n must be large enough for the longest path name. If empty string (all blanks) returned: lunit is not associated with a terminal device in the directory, /dev
isatty: Is this Unit a Terminal?

The function
terminal = isatty( lunit)

lunit
INTEGER*4
Input Logical unit

Return value
LOGICAL*4
Output terminal=true: It is a terminal device terminal=false: It is not a terminal device
is called by:

Example: Determine if lunit is a tty:
character*12 name, ttynam

INTEGER*4 lunit /5/

logical*4 isatty, terminal

terminal = isatty( lunit )

name = ttynam( lunit )

write(*,*) 'terminal = ', terminal, ', name = "', name, '"'

end
The output is:
terminal = T, name = "/dev/ttyp1 "
unlink: Remove a File

The function is called by:
INTEGER*4 unlink

n = unlink ( patnam)

patnam
character*n
Input File name

Return value
INTEGER*4
Output n=0: OK n>0: Error
The function unlink removes the file specified by path name patnam. If this is the last link to the file, the contents of the file are lost.

Example: unlink()--Remove the tunlink.data file:
call unlink( 'tunlink.data' )

end

demo% f77 -silent tunlink.f

demo% ls tunl*

tunlink.f tunlink.data

demo% a.out

demo%ls tunl*

tunlink.f

demo%
See also: unlink(2), link(3F), and perror(3F). Note: the path names cannot be longer than MAXPATHLEN as defined in <sys/param.h>.

wait: Wait for a Process to Terminate

The function is:
INTEGER*4 wait

n = wait( status)

status
INTEGER*4
Output Termination status of the child process

Return value
INTEGER*4
Output n>0: Process ID of the child process n<0: n=System error code; see wait(2).
wait suspends the caller until a signal is received, or one of its child processes terminates. If any child has terminated since the last wait, return is immediate. If there are no children, return is immediate with an error code.

Example: Code fragment using wait():
INTEGER*4 n, status, wait

...

n = wait( status )

if ( n .lt. 0 ) stop 'wait: error'

...

end
See also: wait(2), signal(3F), kill(3F), and perror(3F).

integer4 seed, getuid real4 ran ... seed = 70198 val = getuid() + ran(seed) ...

**TABLE 1-1** Library Routines for 64-bit Environments
Library Routines
malloc64	Allocate memory and return a pointer	page 76
fseeko64	Reposition a large file	page 40
ftello64	Determine position of a large file	page 40
stat64, fstat64, lstat64	Determine status of a file	page 95
time64, ctime64, gmtime64, ltime64	Get system time, convert to character or dissected	page 96
qsort64	Sort the elements of an array	page 83

sqrt(x)	asin(x)	cosd(x)
log(x)	acos(x)	asind(x)
log10(x)	atan(x)	acosd(x)
exp(x)	atan2(x,y)	atand(x)
x**y	sinh(x)	atan2d(x,y)
sin(x)	cosh(x)	aint(x)
cos(x)	tanh(x)	anint(x)
tan(x)	sind(x)	nint(x)

**TABLE 1-2** Single-Precision Math Functions
r_acos( x ) r_acosd( x ) r_acosh( x ) r_acosp( x ) r_acospi( x )	REAL REAL REAL REAL REAL	Function Function Function Function Function	arc cosine -- arc cosh -- --
r_atan( x ) r_atand( x ) r_atanh( x ) r_atanp( x ) r_atanpi( x )	REAL REAL REAL REAL REAL	Function Function Function Function Function	arc tangent -- arc tanh -- --
r_asin( x ) r_asind( x ) r_asinh( x ) r_asinp( x ) r_asinpi( x )	REAL REAL REAL REAL REAL	Function Function Function Function Function	arc sine -- arc sinh -- --
r_atan2(( y, x ) r_atan2d( y, x ) r_atan2pi( y, x )	REAL REAL REAL	Function Function Function	arc tangent -- --
r_cbrt( x ) r_ceil( x ) r_copysign( x, y )	REAL REAL REAL	Function Function Function	cube root ceiling --
r_cos( x ) r_cosd( x ) r_cosh( x ) r_cosp( x ) r_cospi( x )	REAL REAL REAL REAL REAL	Function Function Function Function Function	cosine -- hyperb cos -- --
r_erf( x ) r_erfc( x )	REAL REAL	Function Function	err function --
r_expm1( x ) r_floor( x ) r_hypot( x, y ) r_infinity( )	REAL REAL REAL REAL	Function Function Function Function	(e**x)-1 floor hypotenuse --
r_j0( x ) r_j1( x ) r_jn( x )	REAL REAL REAL	Function Function Function	Bessel -- --
ir_finite( x ) ir_fp_class( x ) ir_ilogb( x ) ir_irint( x ) ir_isinf( x ) ir_isnan( x ) ir_isnormal( x ) ir_issubnormal( x ) ir_iszero( x ) ir_signbit( x )	INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER	Function Function Function Function Function Function Function Function Function Function	-- -- -- -- -- -- -- -- -- --
r_addran() r_addrans( x, p, l, u ) r_lcran() r_lcrans( x, p, l, u ) r_shufrans(x, p, l, u)	REAL n/a REAL n/a n/a	Function Subroutine Function Subroutine Subroutine	random number generators
r_lgamma( x ) r_logb( x ) r_log1p( x ) r_log2( x )	REAL REAL REAL REAL	Function Function Function Function	log gamma -- -- --
r_max_normal() r_max_subnormal() r_min_normal() r_min_subnormal() r_nextafter( x, y ) r_quiet_nan( n ) r_remainder( x, y ) r_rint( x ) r_scalb( x, y ) r_scalbn( x, n ) r_signaling_nan( n ) r_significand( x )	REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL	Function Function Function Function Function Function Function Function Function Function Function Function
r_sin( x ) r_sind( x ) r_sinh( x ) r_sinp( x ) r_sinpi( x )	REAL REAL REAL REAL REAL	Function Function Function Function Function	sine -- hyperb sin -- --
r_sincos( x, s, c ) r_sincosd( x, s, c ) r_sincosp( x, s, c ) r_sincospi( x, s, c )	n/a n/a n/a n/a	Subroutine Subroutine Subroutine Subroutine	sine & cosine -- -- --
r_tan( x ) r_tand( x ) r_tanh( x ) r_tanp( x ) r_tanpi( x )	REAL REAL REAL REAL REAL	Function Function Function Function Function	tangent -- hyperb tan -- --
r_y0( x ) r_y1( x ) r_yn( n, x )	REAL REAL REAL	Function Function Function	bessel -- --

**TABLE 1-3** Double Precision Math Functions
d_acos( x ) d_acosd( x ) d_acosh( x ) d_acosp( x ) d_acospi( x )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function Function Function	arc cosine -- arc cosh -- --
d_atan( x ) d_atand( x ) d_atanh( x ) d_atanp( x ) d_atanpi( x )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function Function Function	arc tangent -- arc tanh -- --
d_asin( x ) d_asind( x ) d_asinh( x ) d_asinp( x ) d_asinpi( x )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function Function Function	arc sine -- arc sinh -- --
d_atan2(( y, x ) d_atan2d( y, x ) d_atan2pi( y, x )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function	arc tangent -- --
d_cbrt( x ) d_ceil( x ) d_copysign( x, x )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function	cube root ceiling --
d_cos( x ) d_cosd( x ) d_cosh( x ) d_cosp( x ) d_cospi( x )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function Function Function	cosine -- hyperb cos -- --
d_erf( x ) d_erfc( x )	DOUBLE PRECISION DOUBLE PRECISION	Function Function	error func --
d_expm1( x ) d_floor( x ) d_hypot( x, y ) d_infinity( )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function Function	(e**x)-1 floor hypotenuse --
d_j0( x ) d_j1( x ) d_jn( x )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function	Bessel -- --
id_finite( x ) id_fp_class( x ) id_ilogb( x ) id_irint( x ) id_isinf( x ) id_isnan( x ) id_isnormal( x ) id_issubnormal( x ) id_iszero( x ) id_signbit( x )	INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER	Function Function Function Function Function Function Function Function Function Function
d_addran() d_addrans(x, p, l, u) d_lcran() d_lcrans(x, p, l, u ) d_shufrans(x, p, l,u)	DOUBLE PRECISION n/a DOUBLE PRECISION n/a n/a	Function Subroutin e Function Subroutin e Subroutin e	random number generators
d_lgamma( x ) d_logb( x ) d_log1p( x ) d_log2( x )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function Function	log gamma -- -- --
d_max_normal() d_max_subnormal() d_min_normal() d_min_subnormal() d_nextafter( x, y ) d_quiet_nan( n ) d_remainder( x, y ) d_rint( x ) d_scalb( x, y ) d_scalbn( x, n ) d_signaling_nan( n ) d_significand( x )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function Function Function Function Function Function Function Function Function Function
d_sin( x ) d_sind( x ) d_sinh( x ) d_sinp( x ) d_sinpi( x )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function Function Function	sine -- hyper sine -- --
d_sincos( x, s, c ) d_sincosd( x, s, c ) d_sincosp( x, s, c ) d_sincospi( x, s, c )	n/a n/a n/a n/a	Subroutin e Subroutin e Subroutin e Subroutin e	sine & cosine -- --
d_tan( x ) d_tand( x ) d_tanh( x ) d_tanp( x ) d_tanpi( x )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function Function Function	tangent -- hyperb tan -- --
d_y0( x ) d_y1( x ) d_yn( n, x )	DOUBLE PRECISION DOUBLE PRECISION DOUBLE PRECISION	Function Function Function	bessel -- --

**TABLE 1-4** Quadruple-Precision `libm` Functions
q_copysign( x, y ) q_fabs( x ) q_fmod( x ) q_infinity( )	REAL16 REAL16 REAL16 REAL16	Function Function Function Function
iq_finite( x ) iq_fp_class( x ) iq_ilogb( x ) iq_isinf( x ) iq_isnan( x ) iq_isnormal( x ) iq_issubnormal( x ) iq_iszero( x ) iq_signbit( x )	INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER INTEGER	Function Function Function Function Function Function Function Function Function
q_max_normal() q_max_subnormal() q_min_normal() q_min_subnormal() q_nextafter( x, y ) q_quiet_nan( n ) q_remainder( x, y ) q_scalbn( x, n ) q_signaling_nan( n )	REAL16 REAL16 REAL16 REAL16 REAL16 REAL16 REAL16 REAL16 REAL*16	Function Function Function Function Function Function Function Function Function

call abort

`INTEGER4 access` `status = access (` name, mode* `)`
name	`character`	Input	File name
mode	`character`	Input	Permissions
Return value	`INTEGER*4`	Output	status=0: OK status>0: Error code

`'r'`	Test for read permission
`'w'`	Test for write permission
`'x'`	Test for execute permission
`' '`	Test for existence of the file

INTEGER4 access, status status = access ( 'taccess.data', 'rw' ) if ( status .eq. 0 ) write(,) "ok" if ( status .ne. 0 ) write(,*) 'cannot read/write', status

INTEGER4 access, status status = access ( 'taccess.data', ' ' ) ! blank mode if ( status .eq. 0 ) write(,) "file exists" if ( status .ne. 0 ) write(,*) 'no such file', status

`INTEGER4 alarm` `n = alarm (` time`,` sbrtn* `)`
time	INTEGER*4	Input	Number of seconds to wait (0=do not call)
sbrtn	Routine name	Input	Subprogram to execute must be listed in an external statement.
Return value	INTEGER*4	Output	Time remaining on the last alarm

integer4 alarm, time / 1 / common / alarmcom / i external sbrtn i = 9 write(,) i nseconds = alarm ( time, sbrtn ) do n = 1,100000 ! Wait until alarm activates sbrtn. r = n ! (any calculations that take enough time) x=sqrt(r) end do write(,*) i end subroutine sbrtn common / alarmcom / i i = 3 ! Do no I/O in this routine. return end

`and(` word1, word2 `)`	Computes bitwise and of its arguments.
`or(` word1, word2 `)`	Computes bitwise inclusive or of its arguments.
`xor(` word1, word2 `)`	Computes bitwise exclusive or of its arguments.
`not(` word `)`	Returns bitwise complement of its argument.
`lshift(` word, nbits `)`	Logical left shift with no end around carry.
`rshift(` word, nbits `)`	Arithmetic right shift with sign extension.
`call bis(` bitnum`,` word `)`	Sets bit bitnum in word to 1.
`call bic(` bitnum`,` word `)`	Clears bit bitnum in word to 0.
`bit(` bitnum`,` word `)`	Tests bit bitnum in word and returns `.true.` if the bit is 1, `.false.` if it is 0.
`call setbit(`bitnum`,`word`,`state`)`	Sets bit bitnum in word to 1 if state is nonzero, and clears it otherwise.

`iand(` m`,` n`)`	Computes the bitwise and of its arguments.
`ior(` m`,` n`)`	Computes the bitwise inclusive or of its arguments.
`ieor(` m`,` n`)`	Computes the bitwise exclusive or of its arguments.
`ishft(` m`,` k`)`	Is a logical shift with no end around carry (left if k>0, right if k<0).
`ishftc(` m`,` k`,` ic`)`	Circular shift: right-most ic bits of m are left-shifted circularly k places.
`ibits(` m`,` i`,` len`)`	Extracts bits: from m, starting at bit i, extracts len bits.
`ibset(` m`,` i`)`	Sets bit: return value is equal to word m with bit number i set to 1.
`ibclr(` m`,` i`)`	Clears bit: return value is equal to word m with bit number i set to 0.
`btest(` m`,` i`)`	Tests bit i in m; returns `.true.` if the bit is 1, and `.false.` if it is 0.

x `= and(` word1, word2`)`
x `= or(` word1, word2`)`
x `= xor(` word1, word2`)`
x `= not(` word`)`
x `= rshift(` word, nbits`)`
x `= lshift(` word, nbits`)`

demo% `cat tandornot.f` print 1, and(7,4), or(7,4), xor(7,4), not(4) 1 format(4x 'and(7,4)', 5x 'or(7,4)', 4x 'xor(7,4)', & 6x 'not(4)'/4o12.11) end demo%`f77 -silent tandornot.f` demo% `a.out` and(7,4) or(7,4) xor(7,4) not(4) 00000000004 00000000007 00000000003 37777777773 demo%

integer*4 lshift, rshift print 1, lshift(7,1), rshift(4,1) 1 format(1x 'lshift(7,1)', 1x 'rshift(4,1)'/2o12.11) end demo%`f77 -silent tlrshift.f` demo% `a.out` lshift(7,1) rshift(4,1) 00000000016 00000000002 demo%

`call bic(` bitnum`,` word`)`
`call bis(` bitnum`,` word`)`
`call setbit(` bitnum`,` word`,` state`)`
`LOGICAL` `bit` x `= bit(` bitnum`,` word`)`

integer4 bitnum/2/, state/0/, word/7/ logical bit print 1, word 1 format(13x 'word', o12.11) call bic( bitnum, word ) print 2, word 2 format('after bic(2,word)', o12.11) call bis( bitnum, word ) print 3, word 3 format('after bis(2,word)', o12.11) call setbit( bitnum, word, state ) print 4, word 4 format('after setbit(2,word,0)', o12.11) print 5, bit(bitnum, word) 5 format('bit(2,word)', L ) end <output*> word 00000000007 after bic(2,word) 00000000003 after bis(2,word) 00000000007 after setbit(2,word,0) 00000000003 bit(2,word) F

`INTEGER4 chdir` n `= chdir(` dirname*`)`
dirname	`character`	Input	Directory name
Return value	`INTEGER*4`	Output	n=0: OK, n>0: Error code

INTEGER*4 chdir, n n = chdir ( 'MyDir' ) if ( n .ne. 0 ) stop 'chdir: error' end

`INTEGER4 chmod` n `= chmod(` name`,` mode*`)`
name	`character`	Input	Path name
mode	`character`	Input	Anything recognized by chmod(1), such as `o-w`, `444`, etc.
Return value	`INTEGER*4`	Output	n = 0: OK; n>0: System error number

character18 name, mode INTEGER4 chmod, n name = 'MyFile' mode = '+w' n = chmod( name, mode ) if ( n .ne. 0 ) stop 'chmod: error' end

`call date(` c`)`
c	`CHARACTER*9`	Output	Variable, array, array element, or character substring

demo% `cat dat1.f` * dat1.f -- Get the date as a character string. character c9 call date ( c ) write(,"(' The date today is: ', A9 )" ) c end demo% `f77 -silent dat1.f` "dat.f", line 2: Warning: Subroutine "date" is not safe after year 2000; use "date_and_time" instead demo% `a.out` Computing time differences using the 2 digit year from subroutine date is not safe after year 2000. The date today is: 9-Jul-98 demo%

`call date_and_time(` date, time, zone, values`)`
date	`CHARACTER*8`	Output	Date, in form CCYYMMDD, where CCYY is the four-digit year, MM the two-digit month, and DD the two-digit day of the month. For example: 19980709
time	`CHARACTER*10`	Output	The current time, in the form hhmmss.sss, where hh is the hour, mm minutes, and ss.sss seconds and milliseconds.
zone	`CHARACTER*5`	Output	The time difference with respect to UTC, expressed in hours and minutes, in the form hhmm
values	`INTEGER*4` `VALUES(8)`	Output	An integer array of 8 elements described below.

`VALUES(1)`	The year, as a 4-digit integer. For example, 1998.
`VALUES(2)`	The month, as an integer from 1 to 12.
`VALUES(3)`	The day of the month, as an integer from 1 to 31.
`VALUES(4)`	The time difference, in minutes, with respect to UTC.
`VALUES(5)`	The hour of the day, as an integer from 1 to 23.
`VALUES(6)`	The minutes of the hour, as an integer from 1 to 59.
`VALUES(7)`	The seconds of the minute, as an integer from 0 to 60.
`VALUES(8)`	The milliseconds of the second, in range 0 to 999.

demo% `cat dtm.f` integer date_time(8) character10 b(3) call date_and_time(b(1), b(2), b(3), date_time) print ,'date_time array values:' print ,'year=',date_time(1) print ,'month_of_year=',date_time(2) print ,'day_of_month=',date_time(3) print ,'time difference in minutes=',date_time(4) print ,'hour of day=',date_time(5) print ,'minutes of hour=',date_time(6) print ,'seconds of minute=',date_time(7) print ,'milliseconds of second=',date_time(8) print , 'DATE=',b(1) print , 'TIME=',b(2) print *, 'ZONE=',b(3) end

date_time array values: year= 2000 month_of_year= 2 day_of_month= 16 time difference in minutes= -420 hour of day= 11 minutes of hour= 49 seconds of minute= 29 milliseconds of second= 236 DATE=20000216 TIME=114929.236 ZONE=-0700

e `= dtime(` tarray`)`
tarray	real(2)	Output	e= -1.0: Error: tarray values are undefined e -1.0: User time in tarray(1) if no error. System time in tarray(2) if no error
Return value	`real`	Output	e= -1.0: Error e -1.0: The sum of tarray(1) and tarray(2)

real e, dtime, t(2) print , 'elapsed:', e, ', user:', t(1), ', sys:', t(2) do i = 1, 10000 k=k+1 end do e = dtime( t ) print , 'elapsed:', e, ', user:', t(1), ', sys:', t(2) end demo% `f77 -silent tdtime.f` demo% `a.out` elapsed: 0., user: 0., sys: 0. elapsed: 0.180000, user: 6.00000E-02, sys: 0.120000 demo%

e `= etime(` tarray`)`
tarray	`real(2)`	Output	e= -1.0: Error: tarray values are undefined. e -1.0: Single Processor: User time in tarray(1). System time in tarray(2) Multiple Processor: Wall clock time in tarray(1), 0.0 in tarray(2)
Return value	`real`	Output	e= -1.0: Error e -1.0: The sum of tarray(1) and tarray(2)

real e, etime, t(2) e = etime(t) ! Startup etime - do not use result do i = 1, 10000 k=k+1 end do e = etime( t ) print *, 'elapsed:', e, ', user:', t(1), `, sys:', t(2) end demo% `f77 -silent tetime.f` demo% `a.out` elapsed: 0.190000, user: 6.00000E-02, sys: 0.130000 demo%

`call exit(` status`)`
status	`INTEGER*4`	Input

... if(dx .lt. 0.) call exit( 0 ) ... end

`call fdate(` string`)`
string	`character*24`	Output

`CHARACTER fdate24` string* `= fdate()`	If used as a function, the calling routine must define the type and size of `fdate`.
Return value	`character*24`	Output

character24 string call fdate( string ) write(,*) string end

Wed Aug 3 15:30:23 1994

character24 fdate write(,*) fdate() end

`INTEGER4 flush` n `= flush(` lunit*`)`
lunit	`INTEGER*4`	Input	Logical unit
Return value	`INTEGER*4`	Output	n = 0 no error n > 0 error number

`INTEGER*4 fork` n`= fork()`
Return value	`INTEGER*4`	Output	n>0: n=Process ID of copy n<0, n=System error code

INTEGER4 fork, pid pid = fork() if(pid.lt.0) stop 'fork error' if(pid.gt.0) then print , 'I am the parent' else print *, 'I am the child' endif

`call free (` ptr`)`
ptr	`pointer`	Input

real x pointer ( ptr, x ) ptr = malloc ( 10000 ) call free ( ptr ) end

`INTEGER4 fseek` n `= fseek(` lunit`,` offset`,` from*`)`
lunit	`INTEGER*4`	Input	Open logical unit
offset	`INTEGER4` or `INTEGER8`	Input	Offset in bytes relative to position specified by from
An `INTEGER*8` offset value is required when compiled for a 64-bit environment, such as Solaris 7, with `-xarch=v9`. If a literal constant is supplied, it must be a 64-bit constant, for example: `100_8`
from	`INTEGER*4`	Input	0=Beginning of file 1=Current position 2=End of file
Return value	`INTEGER*4`	Output	n=0: OK; n>0: System error code

INTEGER*4 fseek, lunit/1/, offset/2/, from/0/, n open( UNIT=lunit, FILE='MyFile' ) n = fseek( lunit, offset, from ) if ( n .gt. 0 ) stop 'fseek error' end

INTEGER4 fseek, lunit/1/, from/0/, n INTEGER8 offset/2/ open( UNIT=lunit, FILE='MyFile' ) n = fseek( lunit, offset, from ) if ( n .gt. 0 ) stop 'fseek error' end

Library | Contents | Previous | Next | Index

`call getarg(` k`,` arg`)`
k	`INTEGER*4`	Input	Index of argument (0=first=command name)
arg	`character*`n	Output	kth argument
n	`INTEGER*4`	Size of arg	Large enough to hold longest argument

`INTEGER4 getc` status* `= getc(` char`)`
char	`character`	Output	Next character
Return value	`INTEGER*4`	Output	status=0: OK status=-1: End of file status>0: System error code or `f77` I/O error code

`INTEGER4 getcwd` status* `= getcwd(` dirname`)`
dirname	`character*`n	Output The path of the current directory is returned	Path name of the current working directory. n must be large enough for longest path name
Return value	`INTEGER*4`	Output	status=0: OK status>0: Error code

`call getenv(` ename`,` evalue`)`
ename	`character*`n	Input	Name of the environment variable sought
evalue	`character*`n	Output	Value of the environment variable found; blanks if not successful

`INTEGER4 getfd` fildes* `= getfd(` unitn`)`
unitn	`INTEGER*4`	Input	External unit number
Return value	`INTEGER4`-or-* `INTEGER*8`	Output	File descriptor if file is connected; -1 if file is not connected An `INTEGER*8` result is returned when compiling for 64-bit environments

irtn `=` c_read`( getfilep(` unitn `),` inbyte`, 1 )`
c_read	C function	Input	User's own C function. See example.
unitn	`INTEGER*4`	Input	External unit number.
`getfilep`	`INTEGER4`-or-* `INTEGER*8`	Return value	File pointer if the file is connected; -1 if the file is not connected. An `INTEGER*8` value is returned when compiling for 64-bit environments

`call idate(` m`,` d`,` y `)` VMS Version
m	`INTEGER*4`	Output	Month (1 - 12)
d	`INTEGER*4`	Output	Day (1 - 7)
y	`INTEGER*4`	Output	Year (1 - 99) Not year 2000 safe!

`ieeer = ieee_flags(` action`,`mode`,`in`,`out`)`
`ieeer = ieee_handler(`action`,`exception`,`hdl`)`
`ieeer = sigfpe(` code`,` hdl`)`
action	`character`	Input
code	`sigfpe_code_type`	Input
mode	`character`	Input
in	`character`	Input
exception	`character`	Input
hdl	`sigfpe_handler_type`	Input
out	`character`	Output
Return value	`INTEGER*4`	Output

action = 'clearall'	mode, in, out, unused; returns 0
action = 'clear' clear mode, in out is unused; returns 0	mode = 'direction'
	mode = 'precision' (on x86 platforms only)
	mode = 'exception'	in = 'inexact' or 'division' or 'underflow' or 'overflow' or 'invalid' or 'all' or 'common'
action = 'set' set floating-point mode,in out is unused; returns 0	mode = 'direction'	in = 'nearest' or 'tozero' or 'positive' or 'negative'
	mode = 'precision' (on x86 only)	in = 'extended' or 'double' or 'single'
	mode = 'exception'	in = 'inexact' or 'division' or 'underflow' or 'overflow' or 'invalid' or 'all' or 'common'
action = 'get' test mode settings in, out may be blank or one of the settings to test returns the current setting depending on mode, or '`not available`' The function returns 0 or the current exception flags if mode = '`exception`'	mode = 'direction'	out = 'nearest' or 'tozero' or 'positive' or 'negative'
	mode = 'precision' (on x86 only)	out = 'extended' or 'double' or 'single'
	mode = 'exception'	out = 'inexact' or 'division' or 'underflow' or 'overflow' or 'invalid' or 'all' or 'common'

action = 'clear' clear user exception handing of in; out is unused	in = 'inexact' or 'division' or 'underflow' or 'overflow' or 'invalid' or 'all' or 'common'
action = 'set' set user exception handing of in; out is address of handler routine, or `SIGFPE_DEFAULT`, or `SIGFPE_ABORT`, or `SIGFPE_IGNORE` defined in `f77/f77_floating point.h`	in = 'inexact' or 'division' or 'underflow' or 'overflow' or 'invalid' or 'all' or 'common'

`sigfpe_code_type`	The type of a `SIGFPE` code.
`sigfpe_handler_type`	The type of a user-definable `SIGFPE` exception handler called to handle a particular `SIGFPE` code.
`SIGFPE_DEFAULT`	A macro indicating default `SIGFPE` exception handling: IEEE exceptions to continue with a default result and to abort for other `SIGFPE` codes.
`SIGFPE_IGNORE`	A macro indicating an alternate `SIGFPE` exception handling, namely to ignore and continue execution.
`SIGFPE_ABORT`	A macro indicating an alternate `SIGFPE` exception handling, namely to abort with a core dump.

`N_IEEE_EXCEPTION`	The number of distinct IEEE floating-point exceptions.
`fp_exception_type`	The type of the `N_IEEE_EXCEPTION` exceptions. Each exception is given a bit number.
`fp_exception_field_type`	The type intended to hold at least `N_IEEE_EXCEPTION` bits corresponding to the IEEE exceptions numbered by `fp_exception_type`. Thus, `fp_inexact` corresponds to the least significant bit and `fp_invalid` to the fifth least significant bit. Some operations can set more than one exception.

`index(`a1`,`a2`)`	Index of first occurrence of string a2 in string a1
`rindex(`a1`,`a2`)`	Index of last occurrence of string a2 in string a1
`lnblnk(`a1`)`	Index of last nonblank in string a1

n `= index(` a1`,` a2`)`
a1	`character`	Input	Main string
a2	`character`	Input	Substring
Return value	`INTEGER`	Output	n>0: Index of first occurrence of a2 in a1 n=0: a2 does not occur in a1.

n `= lnblnk(` a1`)`
a1	`character`	Input	String
Return value	`INTEGER4`or `INTEGER8`	Output	n>0: Index of last nonblank in a1 n=0: a1 is all nonblank `INTEGER*8` returned in 64-bit environments

`call ioinit (` cctl`,` bzro`,` apnd`,` prefix`,` vrbose`)`
cctl	`logical`	Input	True: Recognize carriage control, all formatted output (except unit 0)
bzro	`logical`	Input	True: Treat trailing and imbedded blanks as zeroes.
apnd	`logical`	Input	True: Open files at EoF. Append.
prefix	`character*`n	Input	Nonblank: For unit NN, seek and open file prefixNN
vrbose	`logical`	Input	True: Report `ioinit` activity as it happens

status `= kill(` pid`,` signum`)`
pid	`INTEGER*4`	Input	Process ID of one of the user's processes
signum	`INTEGER*4`	Input	Valid signal number. See signal(3).
Return value	`INTEGER*4`	Output	status=0: OK status>0: Error code

status `= link(` name1`,` name2`)`
`INTEGER4 symlnk` status* `= symlnk(` name1`,` name2 `)`
name1	`character*`n	Input	Path name of an existing file
name2	`character*`n	Input	Path name to be linked to the file, name1. name2 must not already exist.
Return value	`INTEGER*4`	Output	status=0: OK status>0: System error code

k `= loc(` arg`)`
arg	Any type	Input	Variable or array
Return value	`INTEGER4`-or-* `INTEGER*8`	Output	Address of arg
Return value	Returns an `INTEGER*8` pointer when compiled to run in a 64-bit environment with `-xarch=v9`. See Note below.

ival `= isetjmp(` env`)`
env	`INTEGER*4`	Output	env is a 12-element integer array. In 64-bit environments it must be declared `INTEGER*8`
Return value	`INTEGER*4`	Output	ival = 0 if `isetjmp` is called explicitly ival 0 if `isetjmp` is called through `longjmp`

Chapter 1

Fortran Library Routines

Data Type Considerations

64-Bit Environments

Fortran Math Functions

Intrinsic Math Functions

Single-Precision Functions

Double-Precision Functions

Quad-Precision Functions

abort: Terminate and Write Core File

access: Check File Permissions or Existence

alarm: Call Subroutine After a Specified Time

bit: Bit Functions: and, or, ..., bit, setbit, ...

Usage: and, or, xor, not, rshift, lshift

Usage: bic, bis, bit, setbit call bic( bitnum, word ) call bis( bitnum, word ) call setbit( bitnum, word, state ) LOGICAL bit x = bit( bitnum, word )

chdir: Change Default Directory

chmod: Change the Mode of a File

date: Get Current Date as a Character String

date_and_time: Get Date and Time

dtime, etime: Elapsed Execution Time

dtime: Elapsed Time Since the Last dtime Call

etime: Elapsed Time Since Start of Execution

exit: Terminate a Process and Set the Status

fdate: Return Date and Time in an ASCII String

flush: Flush Output to a Logical Unit

fork: Create a Copy of the Current Process

free: Deallocate Memory Allocated by Malloc

fseek, ftell: Determine Position and Reposition a File

fseek: Reposition a File on a Logical Unit

ftell: Return Current Position of File

fseeko64, ftello64: Determine Position and Reposition a Large File

fseeko64: Reposition a File on a Logical Unit

ftello64: Return Current Position of File

getarg, iargc: Get Command-Line Arguments

getarg: Get a Command-Line Argument

iargc: Get the Number of Command-Line Arguments

getc, fgetc: Get Next Character

getc: Get Next Character from stdin

fgetc: Get Next Character from Specified Logical Unit

getcwd: Get Path of Current Working Directory

getenv: Get Value of Environment Variables

getfd: Get File Descriptor for External Unit Number

getfilep: Get File Pointer for External Unit Number

getlog: Get User's Login Name

getpid: Get Process ID

getuid, getgid: Get User or Group ID of Process

getuid: Get User ID of the Process

getgid: Get Group ID of the Process

hostnm: Get Name of Current Host

idate: Return Current Date

ieee_flags,ieee_handler,sigfpe: IEEE Arithmetic

f77_floatingpoint.h: Fortran IEEE Definitions

index,rindex,lnblnk: Index or Length of Substring

index: First Occurrence of a Substring in a String

rindex: Last Occurrence of a Substring in a String

lnblnk: Last Nonblank in a String

inmax: Return Maximum Positive Integer

ioinit: Initialize I/O Properties

Persistence of File I/O Properties

Internal Flags

Source Code

Usage: ioinit

Restrictions

Description of Arguments

cctl (Carriage Control)

bzro (Blanks)

apnd (Append)

prefix (Automatic File Connection)

vrbose (IOINIT Activity)

itime: Current Time

kill: Send a Signal to a Process

link, symlnk: Make a Link to an Existing File

link: Create a Link to an Existing File

symlnk: Create a Symbolic Link to an Existing File

loc: Return the Address of an Object

long, short: Integer Object Conversion

long: Convert a Short Integer to a Long Integer

short: Convert a Long Integer to a Short Integer

longjmp, isetjmp: Return to Location Set by isetjmp

isetjmp: Set the Location for longjmp

`abort`: Terminate and Write Core File

`access`: Check File Permissions or Existence

`alarm`: Call Subroutine After a Specified Time

`bit`: Bit Functions: `and`, `or`, ..., `bit`, `setbit`, ...

Usage: `and`, `or`, `xor`, `not`, `rshift`, `lshift`

Usage: `bic`, `bis`, `bit`, `setbit`

`call bic(` bitnum`,` word`)`

`call bis(` bitnum`,` word`)`

`call setbit(` bitnum`,` word`,` state`)`

`LOGICAL` `bit`

x `= bit(` bitnum`,` word`)`

`chdir`: Change Default Directory

`chmod`: Change the Mode of a File

`date`: Get Current Date as a Character String

`date_and_time`: Get Date and Time

`dtime`, `etime`: Elapsed Execution Time

`dtime`: Elapsed Time Since the Last `dtime` Call

`etime`: Elapsed Time Since Start of Execution

`exit`: Terminate a Process and Set the Status

`fdate`: Return Date and Time in an ASCII String

`flush`: Flush Output to a Logical Unit

`fork`: Create a Copy of the Current Process

`free`: Deallocate Memory Allocated by Malloc

`fseek`, `ftell`: Determine Position and Reposition a File

`fseek`: Reposition a File on a Logical Unit

`ftell`: Return Current Position of File

`fseeko64`, `ftello64`: Determine Position and Reposition a Large File

`fseeko64`: Reposition a File on a Logical Unit

`ftello64`: Return Current Position of File

`getarg`, `iargc`: Get Command-Line Arguments

`getarg`: Get a Command-Line Argument

`iargc`: Get the Number of Command-Line Arguments

`getc`, `fgetc`: Get Next Character

`getc`: Get Next Character from `stdin`

`fgetc`: Get Next Character from Specified Logical Unit

`getcwd`: Get Path of Current Working Directory

`getenv`: Get Value of Environment Variables

`getfd`: Get File Descriptor for External Unit Number

`getfilep`: Get File Pointer for External Unit Number

`getlog`: Get User's Login Name

`getpid`: Get Process ID

`getuid`, `getgid`: Get User or Group ID of Process

`getuid`: Get User ID of the Process

`getgid`: Get Group ID of the Process

`hostnm`: Get Name of Current Host

`idate`: Return Current Date

`ieee_flags,ieee_handler, sigfpe`: IEEE Arithmetic

`f77_floatingpoint.h`: Fortran IEEE Definitions

`index,rindex,lnblnk`: Index or Length of Substring

`index`: First Occurrence of a Substring in a String

`rindex`: Last Occurrence of a Substring in a String

`lnblnk`: Last Nonblank in a String

`inmax`: Return Maximum Positive Integer

`ioinit`: Initialize I/O Properties

Usage: `ioinit`

vrbose (`IOINIT` Activity)

`itime`: Current Time

`kill`: Send a Signal to a Process

`link`, `symlnk`: Make a Link to an Existing File

`link:` Create a Link to an Existing File

`symlnk:` Create a Symbolic Link to an Existing File

`loc`: Return the Address of an Object

`long`, `short`: Integer Object Conversion

`long`: Convert a Short Integer to a Long Integer

`short`: Convert a Long Integer to a Short Integer

`longjmp`, `isetjmp`: Return to Location Set by `isetjmp`

`isetjmp`: Set the Location for `longjmp`

`longjmp`: Return to the Location Set by `isetjmp`

`malloc,` `malloc64`: Allocate Memory and Get Address

`mvbits`: Move a Bit Field

`perror`, `gerror`, `ierrno`: Get System Error Messages

`perror`: Print Message to Logical Unit 0, `stderr`

`gerror`: Get Message for Last Detected System Error

`ierrno`: Get Number for Last Detected System Error

`putc`, `fputc`: Write a Character to a Logical Unit

`putc`: Write to Logical Unit 6

`fputc`: Write to Specified Logical Unit

`qsort,qsort64`: Sort the Elements of a One-Dimensional Array

`ran`: Generate a Random Number Between 0 and 1

`rand`, `drand`, `irand`: Return Random Values

`rename`: Rename a File

`secnds`: Get System Time in Seconds, Minus Argument

t `= secnds(` t0`)`

t0
`REAL`
Input Constant, variable, or array element

Return Value
`REAL`
Output Number of seconds since midnight, minus t0

`sh`: Fast Execution of an `sh` Command

`signal`: Change the Action for a Signal

`sleep`: Suspend Execution for an Interval

k `= malloc(` n`)`
n	`INTEGER*4`	Input	Number of bytes of memory
Return value	`INTEGER4` or `INTEGER8`	Output	k>0: k=address of the start of the block of memory allocated k=0: Error
Return value	An `INTEGER*8` pointer value is returned when compiled for a 64-bit environment with `-xarch=v9`. See Note below.

k `= malloc64(` n`)`
n	`INTEGER*8`	Input	Number of bytes of memory
Return value	`INTEGER*8`	Output	k>0: k=address of the start of the block of memory allocated k=0: Error

`call mvbits(` src`,` ini1`,` nbits`,` des`,` ini2`)`
src	`INTEGER*4`	Input	Source
ini1	`INTEGER*4`	Input	Initial bit position in the source
nbits	`INTEGER*4`	Input	Number of bits to move
des	`INTEGER*4`	Output	Destination
ini2	`INTEGER*4`	Input	Initial bit position in the destination

`perror`	Print a message to Fortran logical unit 0, `stderr`.
`gerror`	Get a system error message (of the last detected system error)
`ierrno`	Get the error number of the last detected system error.

`call qsort(` array`,` len`,` isize`,` compar `)` `call qsort64(` array`,` len8`,` isize8`,` compar`)`
array	`array`	Input	Contains the elements to be sorted
len	`INTEGER*4`	Input	Number of elements in the array.
len8	`INTEGER*8`	Input	Number of elements in the array
isize	`INTEGER*4`	Input	Size of an element, typically: 4 for integer or real 8 for double precision or complex 16 for double complex Length of character object for character arrays
isize8	`INTEGER*8`	Input	Size of an element, typically: 4_8 for integer or real 8_8 for double precision or complex 16_8 for double complex Length of character object for character arrays
compar	function name	Input	Name of a user-supplied `INTEGER2` function. Determines sorting order: compar(arg1,arg2*)

Negative	If arg1 is considered to precede arg2
Zero	If arg1 is equivalent to arg2
Positive	If arg1 is considered to follow arg2

r = ran( i )
i	`INTEGER*4`	Input	Variable or array element
r	`REAL`	Output	Variable or array element

i = irand( k ) r = rand( k ) d = drand( k )
k	`INTEGER*4`	Input	k=0: Get next random number in the sequence k=1: Restart sequence, return first number k>0: Use as a seed for new sequence, return first number
`rand`	`REAL*4`	Output
`drand`	`REAL*8`	Output
`irand`	`INTEGER*4`	Output

t `= secnds(` t0`)`
t0	`REAL`	Input	Constant, variable, or array element
Return Value	`REAL`	Output	Number of seconds since midnight, minus t0

`INTEGER4 signal` or `INTEGER8 signal` n `= signal(` signum`,` proc`,` flag `)`
signum	`INTEGER*4`	Input	Signal number; see signal(3)
proc	Routine name	Input	Name of user signal handling routine; must be in an external statement
flag	`INTEGER*4`	Input	flag < 0: Use proc as the signal handler flag 0: Ignore proc; pass flag as the action: flag `= 0`: Use the default action flag = 1: Ignore this signal
Return value	`INTEGER*4`	Output	n=-1: System error n>0: Definition of previous action n>1: n=Address of routine that would have been called n<-1: If signum is a valid signal number, then: n=address of routine that would have been called. If signum is a not a valid signal number, then: n is an error number.
	`INTEGER*8`		On 64-bit environments, `signal` and the variables receiving its output must be declared `INTEGER*8`