Man Page issubnormal.3m


     ieee_sun, fp_class, isinf,  isnormal,  issubnormal,  iszero,
     signbit,     nonstandard_arithmetic,    standard_arithmetic,
     ieee_retrospective - miscellaneous functions for IEEE arith-


     cc [ flag ... ] file ...  -lsunmath -lm [ library ... ]

     #include <sunmath.h>

     enum fp_class_type fp_class(double x);

     int isinf(double x);

     int isnormal(double x);

     int issubnormal(double x);

     int iszero(double x);

     int signbit(double x);

     void nonstandard_arithmetic(void);

     void standard_arithmetic(void);

     #include <stdio.h>

     void ieee_retrospective(FILE *f);


     Please    see    copysign(3M),     ilogb(3M),     isnan(3M),
     nextafter(3M), remainder(3M), and scalbn(3M), for a descrip-
     tion  of  a  few  more  commonly  used  (and   standardized)
     ANSI/IEEE Std 754-1985 related functions.

     Most of the functions provide capabilities suggested in  the
     Appendix of ANSI/IEEE Std 754-1985.

     fp_class(x) corresponds to the IEEE's class() and classifies
     x as zero, subnormal, normal, oo, or quiet or signaling NaN;
     <floatingpoint.h> defines enum fp_class_type.

     The following functions return 0 if the indicated  condition
     is not satisfied:
          isinf(x)       returns 1 if x is oo
          isnormal(x)    returns 1 if x is normal
          issubnormal(x) returns 1 if x is subnormal
          iszero(x)      returns 1 if x is zero
          signbit(x)     returns 1 if x's sign bit is set

     nonstandard_arithmetic() and standard_arithmetic() are mean-
     ingful on systems that provide an alternative faster mode of
     floating-point arithmetic  that  does  not  conform  to  the
     default  IEEE  Standard. Nonstandard modes vary among imple-
     mentations; nonstandard mode may, for  instance,  result  in
     setting  subnormal  results to zero or in treating subnormal
     operands   as   zero,   or   both,   or   something    else.
     standard_arithmetic()  reverts to the default standard mode.
     On systems that provide only one mode, these functions  have
     no effect.

     ieee_retrospective(f) prints a message to the FILE *f  list-
     ing  all  non-default  floating-point  modes  and  status in
     effect  when  called,  including  IEEE  accrued   exception-
     occurred  status bits, IEEE rounding direction and precision
     modes, IEEE trap-enable modes,  and  nonstandard  arithmetic
     mode.   ieee_retrospective(f)  is intended to be used at the
     end of a program to indicate exceptional floating-point con-
     ditions that might have affected the result.

     A program can  explicitly  call  ieee_retrospective  at  any
     time. Fortran programs compiled with f95 in -f77 compatibil-
     ity mode automatically call ieee_retrospective  before  they
     exit.  C/C++ programs and Fortran programs compiled with f95
     in   the   default   mode   do   not   automatically    call
     ieee_retrospective.   The  f95  compiler enables trapping on
     common exceptions by default, so  unless  a  program  either
     explicitly  disables  trapping or installs a SIGFPE handler,
     it will immediately abort when such an exception occurs.  In
     -f77  compatibility mode, the compiler does not enable trap-
     ping, so when floating point exceptions occur,  the  program
     continues  execution  and  reports  those exceptions via the
     ieee_retrospective output on exit.


     copysign(3M), ieee_flags(3M),  ieee_handler(3M),  ilogb(3M),
     isnan(3M),    nextafter(3M),    remainder(3M),   scalbn(3M),