Chapter 3 Fortran Compiler Options

This chapter details the command–line options for the f95 compiler.

• A description of the syntax used for compiler option flags starts at 3.1 Command Syntax.

• Summaries of options arranged by functionality starts at 3.3 Options Summary.

• The complete reference detailing each compiler option flag starts at 3.4 Options Reference.

3.1 Command Syntax

The general syntax of the compiler command line is:

f95 [options] list_of_files  additional_options

Items in square brackets indicate optional parameters. The brackets are not part of the command. The options are a list of option keywords prefixed by dash (–). Some keyword options take the next item in the list as an argument. The list_of_files is a list of source, object, or library file names separated by blanks. Also, there are some options that must appear after the list of source files, and these could include additional lists of files (for example, -B, -l, and -L).

3.2 Options Syntax

Typical compiler option formats are:

The following typographical conventions are used when describing the individual options:

Brackets, pipe, and ellipsis are meta characters used in the descriptions of the options and are not part of the options themselves.

Some general guidelines for options are:

• –lx is the option to link with library libx.a. It is always safer to put -lx after the list of file names to insure the order libraries are searched.

• In general, processing of the compiler options is from left to right, allowing selective overriding of macro options (options that include other options). This rule does not apply to linker options. However, some options, -I, -L, and -R for example, accumulate values rather than override previous values when repeated on the same command line.

• In an optional list of choices, such as -xhasc[={yes|no}], the first choice listed is the value assumed when the option flag appears on the command line without a value. For example, -xhasc is equivalent to -xhasc=yes.

• Source files, object files, and libraries are compiled and linked in the order in which they appear on the command line.

3.3 Options Summary

In this section, the compiler options are grouped by function to provide an easy reference. The details will be found on the pages in the following sections, as indicated.

Note that not all options are available on both SPARC and x64/x86 platforms. Check the detailed reference section for availability.

The following table summarizes the f95 compiler options by functionality. The table does not include obsolete and legacy option flags. Some flags serve more than one purpose and appear more than once.

3.3.1 Commonly Used Options

The compiler has many features that are selectable by optional command–line parameters. The short list below of commonly used options is a good place to start.

3.3.2 Macro Flags

Some option flags are macros that expand into a specific set of other flags. These are provided as a convenient way to specify a number of options that are usually expressed together to select a certain feature.

Settings that follow the macro flag on the command line override or add to the the expansion of the macro.

3.3.3 Backward Compatibility and Legacy Options

The following options are provided for backward compatibility with earlier compiler releases, and certain Fortran legacy capabilities.

Use of these option flags is not recommended for producing portable Fortran programs.

3.3.4 Obsolete Option Flags

The following options are considered obsolete and should not be used. They might be removed from later releases of the compiler.

3.4 Options Reference

This section describes all of the f95 compiler command–line option flags, including various risks, restrictions, caveats, interactions, examples, and other details.

Unless indicated otherwise, each option is valid on both SPARC and x64/x86 platforms. Option flags valid only on SPARC platforms are marked (SPARC). Option flags valid only on x64/x86 platforms are marked (x86).

Option flags marked (Obsolete) are obsolete and should not be used. In many cases they have been superceded by other options or flags that should be used instead.

3.4.1 –a

(Obsolete) Profile by basic block using tcov, old style.

This is the old style of basic block profiling for tcov. See -xprofile=tcov for information on the new style of profiling and the tcov(1) man page for more details.

3.4.2 –aligncommon[={1|2|4|8|16}]

Specify the alignment of data in common blocks and standard numeric sequence types.

The value indicates the maximum alignment (in bytes) for data elements within common blocks and standard numeric sequence types.

A standard numeric sequence type is a derived type containing a SEQUENCE statement and only default component data types ( INTEGER, REAL, DOUBLEPRECISION, COMPLEX without KIND= or * size) . Any other type, such as REAL*8, will make the type non-standard.

For example, -aligncommon=4 would align data elements with natural alignments of 4 bytes or more on 4-byte boundaries.

This option does not affect data with natural alignment smaller than the specified size.

Without -aligncommon, the compiler aligns elements in common blocks and numeric sequence types on (at most) 4-byte boundaries.

Specifying -aligncommon without a value defaults to 1 - all common block and numeric sequence type elements align on byte boundaries (no padding between elements).

-aligncommon=16 reverts to -aligncommon=8 on platforms that are not 64-bit enabled.

Do not use -aligncommon=1 with -xmemalign as these declarations will conflict and could cause a segmentation fault on some platforms and configurations.

3.4.3 –ansi

Identify many nonstandard extensions.

Warning messages are issued for any uses of non–standard Fortran extensions in the source code.

3.4.4 –arg=local

Preserve actual arguments over ENTRY statements.

When you compile a subprogram with alternate entry points with this option, f95 uses copy/restore to preserve the association of dummy and actual arguments.

This option is provided for compatibility with legacy Fortran 77 programs. Code that relies on this option is non-standard.

3.4.5 –autopar

Enable automatic loop parallelization.

Finds and parallelizes appropriate loops for running in parallel on multiple processors. Analyzes loops for inter–iteration data dependencies and loop restructuring. If the optimization level is not specified -O3 or higher, it will automatically be raised to -O3.

Also specify the -stackvar option when using any of the parallelization options, including -autopar. The -stackvar option may provide better performance when using -autopar because it may allow the optimizer to detect additional opportunities for parallelization. See the description of the -stackvar option for information on how to set the sizes for the main thread stack and for the slave thread stacks.

Avoid -autopar if the program already contains explicit calls to the libthread threads library. See note in 3.4.56 –mt.

The -autopar option is not appropriate on a single–processor system, and the compiled code will generally run slower.

To run a parallelized program in a multithreaded environment, you must set the PARALLEL (or OMP_NUM_THREADS) environment variable prior to execution. This tells the runtime system the maximum number of threads the program can create. The default is 1. In general, set the PARALLEL or OMP_NUM_THREADS variable to the number of available virtual processors on the target platform, which can be determined by using the Solaris psrinfo(1) command.

If you use -autopar and compile and link in one step, the multithreading library and the thread–safe Fortran runtime library will automatically be linked. If you use -autopar and compile and link in separate steps, then you must also link with -autopar to insure linking the appropriate libraries.

The—reduction option may also be useful with —autopar.

Refer to the Fortran Programming Guide for more information on parallelization. For explicit, user-controlled parallelization, use OpenMP directives and the —xopenmp option.

3.4.6 –B{static|dynamic}

Prefer dynamic or require static library linking.

No space is allowed between -B and dynamic or static. The default, without -B specified, is -Bdynamic.

• –Bdynamic: Prefer dynamic linking (try for shared libraries).

• –Bstatic: Require static linking (no shared libraries).

Also note:

• If you specify static, but the linker finds only a dynamic library, then the library is not linked with a warning that the “library was not found.”

• If you specify dynamic, but the linker finds only a static version, then that library is linked, with no warning.

You can toggle -Bstatic and -Bdynamic on the command line. That is, you can link some libraries statically and some dynamically by specifying -Bstatic and -Bdynamic any number of times on the command line, as follows:

f95 prog.f -Bdynamic -lwells -Bstatic -lsurface

These are loader and linker options. Compiling and linking in separate steps with -Bx on the compile command will require it in the link step as well.

You cannot specify both -Bdynamic and -dn on the command line because -dn disables linking of dynamic libraries.

In a 64-bit Solaris environment, many system libraries are available only as shared dynamic libraries. These include libm.so and libc.so (libm.a and libc.a are not provided). This means that -Bstatic and -dn may cause linking errors in 64-bit Solaris environments. Applications must link with the dynamic libraries in these cases.

Mixing static Fortran runtime system libraries with dynamic Fortran runtime system libraries is not recommended and can result in linker errors or silent data corruption. Always link with the latest shared dynamic Fortran runtime system libraries.

See the Fortran Programming Guide for more information on static and dynamic libraries.

3.4.7 –C

Check array references for out of range subscripts and conformance at runtime.

Subscripting arrays beyond their declared sizes may result in unexpected results, including segmentation faults. The -C option checks for possible array subscript violations in the source code and during execution. -C also adds runtime checks for array conformance in array syntax expressions

Specifying -C may make the executable file larger.

If the -C option is used, array subscript violations are treated as an error. If an array subscript range violation is detected in the source code during compilation, it is treated as a compilation error.

If an array subscript violation can only be determined at runtime, the compiler generates range–checking code into the executable program. This may cause an increase in execution time. As a result, it is appropriate to enable full array subscript checking while developing and debugging a program, then recompiling the final production executable without subscript checking.

3.4.8 –c

Compile only; produce object .o files, but suppress linking.

Compile a .o file for each source file. If only a single source file is being compiled, the -o option can be used to specify the name of the .o file written.

3.4.9 –copyargs

Allow assignment to constant arguments.

Allow a subprogram to change a dummy argument that is a constant. This option is provided only to allow legacy code to compile and execute without a runtime error.

• Without -copyargs, if you pass a constant argument to a subroutine, and then within the subroutine try to change that constant, the run aborts.

• With -copyargs, if you pass a constant argument to a subroutine, and then within the subroutine change that constant, the run does not necessarily abort.

Code that aborts unless compiled with -copyargs is, of course, not Fortran standard compliant. Also, such code is often unpredictable.

3.4.10 –Dname[=def]

Define symbol name for the preprocessor.

This option only applies to .F, .F90, .F95, and .F03 source files.

–Dname=def Define name to have value def

–Dname Define name to be 1

On the command line, this option will define name as if:

#define name[=def]

had appears in the source file. If no =def specified, the name name is defined as the value 1. The macro symbol name is passed on to the preprocessor fpp (or cpp— see the -xpp option) for expansion.

The predefined macro symbols have two leading underscores. The Fortran syntax may not support the actual values of these macros—they should appear only in fpp or cpp preprocessor directives. (Note the two leading underscores.)

• The product version is predefined (in hex) in _ _SUNPRO_F90, and _ _SUNPRO_F95. For example _ _SUNPRO_F95 is 0x830 for the Sun Studio 12 release.

• The following macros are predefined on appropriate systems:

  _ _sparc, _ _unix, _ _sun, _ _SVR4, __i386 , _ _SunOS_5_6, _ _SunOS_5_7, _ _SunOS_5_8, _ _SunOS_5_9, _ _SunOS_5_10

  For instance, the value _ _sparc is defined on SPARC systems.

• The following are predefined with no underscores, but they might be deleted in a future release: sparc, unix, sun

• On SPARC V9 systems, the _ _sparcv9 macro is also defined.

• On 64-bit x86 systems, the macros __amd64 and __x86_64 are defined.

Compile with the verbose option (-v) to see the definitions created by the compiler.

You can use these values in such preprocessor conditionals as the following:

#ifdef _ _sparc

f95 uses the fpp(1) preprocessor by default. Like the C preprocessor cpp(1), fpp expands source code macros and enables conditional compilation of code. Unlike cpp, fpp understands Fortran syntax, and is preferred as a Fortran preprocessor. Use the -xpp=cpp flag to force the compiler to specifically use cpp rather than fpp.

3.4.11 –dalign

Align COMMON blocks and standard numerical sequence types, and generate faster multi-word load/stores.

This flag changes the data layout in COMMON blocks, numeric sequence types, and EQUIVALENCE classes, and enables the compiler to generate faster multi-word load/stores for that data.

The data layout effect is that of the -f flag: double- and quad-precision data in COMMON blocks and EQUIVALENCE classes are laid out in memory along their “natural” alignment, which is on 8-byte boundaries (or on 16-byte boundaries for quad-precision when compiling for 64-bit environments with -m64). The default alignment of data in COMMON blocks is on 4-byte boundaries. The compiler is also allowed to assume natural alignment and generate faster multi-word load/stores to reference the data.

Using -dalign along with -xtypemap=real:64,double:64,integer:64 also causes 64-bit integer variables to be double-word aligned on SPARC processors.

-dalign may result in nonstandard alignment of data, which could cause problems with variables in EQUIVALENCE or COMMON and may render the program non-portable if -dalign is required.

-dalign is a macro equivalent to:

-xmemalign=8s -aligncommon=16 on SPARC platforms

-aligncommon=8 on 32-bit x86 platforms

-aligncommon=16 on 64-bit x86 platforms.

If you compile one subprogram with -dalign, compile all subprograms of the program with -dalign. This option is included in the -fast option.

Note that because -dalign invokes -aligncommon, standard numeric sequence types are also affected by this option. See 3.4.2 –aligncommon[={1|2|4|8|16}]

3.4.12 –dbl_align_all[={yes|no}]

Force alignment of data on 8–byte boundaries

The value is either yes or no. If yes, all variables will be aligned on 8–byte boundaries. Default is -dbl_align_all=no.

When compiling for 64-bit environments with -m64, this flag will align quad-precision data on 16-byte boundaries.

This flag does not alter the layout of data in COMMON blocks or user-defined structures.

Use with -dalign to enable added efficiency with multi-word load/stores.

If used, all routines must be compiled with this flag.

3.4.13 –depend[={yes|no}]

Analyze loops for inter-iteration data dependencies and performs loop restructuring. Loop restructuring includes loop interchange, loop fusion, scalar replacement, and elimination of "dead" array assignments.

On SPARC platforms, -xdepend is turned on for all optimization levels -xO3 and above, and is off for lower opt levels. Also, an explicit setting of -xdepend overrides any implicit setting.

On x86 platforms, if optimization is not at -xO3 or higher, the compiler raises the optimization to -xO3 and issues a warning.

If you do not specify -xdepend, the default is -xdepend=no which means the compiler does not analyze loops for data dependencies. If you specify -xdepend but do not specify an argument, the compiler sets the option to -xdepend=yes which means the compiler analyzes loops for data dependencies.

Dependency analysis is included in -xautopar. The dependency analysis is done at compile time. Dependency analysis may help on single-processor systems. However, if you try -xdepend on single-processor systems, you should not also specify -xautopar , otherwise the -xdepend optimization is done for multiple-processor systems.

3.4.14 –dn

Disallow dynamic libraries. See 3.4.16 –d{y|n}.

3.4.15 –dryrun

Show commands built by the f95 command-line driver, but do not compile.

Useful when debugging, this option displays the commands and suboptions the compiler will invoke to perform the compilation.

3.4.16 –d{y|n}

Allow or disallow dynamic libraries for the entire executable.

• –dy: Yes, allow dynamic/shared libraries.

• –dn: No, do not allow dynamic/shared libraries.

The default, if not specified, is -dy.

Unlike -Bx, this option applies to the whole executable and need appear only once on the command line.

–dy|–dn are loader and linker options. If you compile and link in separate steps with these options, then you need the same option in the link step.

In a 64-bit Solaris environment, many system libraries are not available only as shared dynamic libraries. These include libm.so and libc.so (libm.a and libc.a are not provided). This means that -dn and -Bstatic may cause linking errors in 64-bit Solaris environments and 32-bit x86 Solaris platforms, and all 32-bit Solaris platforms starting with the Solaris 10 release. Applications must link with the dynamic libraries in these cases.

3.4.17 –e

Accept extended length input source line.

Extended source lines can be up to 132 characters long. The compiler pads on the right with trailing blanks to column 132. If you use continuation lines while compiling with -e, then do not split character constants across lines, otherwise, unnecessary blanks may be inserted in the constants.

3.4.18 –erroff[={%all|%none|taglist}]

Suppress warning messages listed by tag name.

Suppress the display of warning messages specified in the comma–separated list of tag names taglist. If %all, suppress all warnings, which is equivalent to the -w option. If %none, no warnings are suppressed. —erroff without an argument is equivalent to —erroff=%all.

Example:

f95 -erroff=WDECL_LOCAL_NOTUSED ink.f

Use the -errtags option to see the tag names associated with warning messages.

3.4.19 –errtags[={yes|no}]

Display the message tag with each warning message.

With-errtags=yes, the compiler’s internal error tag name will appear along with warning messages. -errtags alone is equivalent to -errtags=yes.

The default is not to display the tag (-errtags=no).

demo% f95 -errtags ink.f
ink.f:
 MAIN:
"ink.f", line 11: Warning: local variable "i" never used (WDECL_LOCAL_NOTUSED)  

3.4.20 –errwarn[={%all|%none|taglist}]

Treat warning messages as errors.

The taglist specifies a list of comma-separated tag names of warning messages that should be treated as errors. If %all, treat all warnings as errors. If %none, no warnings are treated as errors.

See also -errtags.

3.4.21 –ext_names=e

Create external names with or without trailing underscores.

e must be either plain, underscores, or fsecond-underscore The default is underscores.

–ext_names=plain: Do not add trailing underscore.

–ext_names=underscores: Add trailing underscore.

–ext_names=fsecond-underscore: Append two underscores to external names that contain an underscore, and a single underscore to those that do not.

An external name is a name of a subroutine, function, block data subprogram, or labeled common. This option affects both the name of the routine’s entry point and the name used in calls to it. Use this flag to allow Fortran routines to call (and be called by) other programming language routines.

fsecond-underscore is provided for compatibility with gfortran.

3.4.22 –F

Invoke the source file preprocessor, but do not compile.

Apply the fpp preprocessor to .F, .F90, .F95, and .F03 source files listed on the command line, and write the processed result on a file with the same name but with filename extension changed to .f (or .f95 or .f03), but do not compile.

Example:

f95 -F source.F

writes the processed source file to source.f

fpp is the default preprocessor for Fortran. The C preprocessor, cpp, can be selected instead by specifying -xpp=cpp.

3.4.23 –f

Align double- and quad-precision data in COMMON blocks.

-f is a legacy option flag equivalent to -aligncommon=16. Use of -aligncommon is preferred.

The default alignment of data in COMMON blocks is on 4-byte boundaries. -f changes the data layout of double- and quad-precision data in COMMON blocks and EQUIVALENCE classes to be placed in memory along their “natural” alignment, which is on 8-byte boundaries (or on 16-byte boundaries for quad-precision when compiling for 64-bit SPARC environments with -m64).

-f may result in nonstandard alignment of data, which could cause problems with variables in EQUIVALENCE or COMMON and may render the program non-portable if -f is required.

Compiling any part of a program with -f requires compiling all subprograms of that program with -f.

By itself, this option does not enable the compiler to generate faster multi-word fetch/store instructions on double and quad precision data. The -dalign option does this and invokes -f as well. Use of -dalign is preferred over the older -f. See 3.4.11 –dalign. Because -dalign is part of the -fast option, so is -f.

3.4.24 –f77[=list]

Select Fortran 77 compatibility mode.

This option flag enables porting legacy Fortran 77 source programs, including those with language extensions accepted by the f77 compiler, to the f95 Fortran compiler.

list is a comma-separated list selected from the following possible keywords:

All keywords can be prefixed by no% to disable the feature, as in:

-f77=%all,no%backslash

The default, when -f77 is not specified, is -f77=%none. Using -f77 without a list is equivalent to specifying -f77=%all.

Exceptions Trapping and -f77:

Specifying -f77 does not change the Fortran trapping mode, which is -ftrap=common. f95 differs from the Fortran 77 compiler’s behavior regarding arithmetic exception trapping. The Fortran 77 compiler allowed execution to continue after an arithmetic exception occurred. Compiling with -f77 also causes the program to call ieee_retrospective on program exit to report on any arithmetic exceptions that might have occurred. Specify -ftrap=%none following the -f77 option flag on the command line to mimic the original Fortran 77 behavior.

See 4.12 Mixing Languages for complete information on f77 compatibility and Fortran 77 to Fortran 95 migration.

See also the -xalias flag for handling non-standard programming syndromes that may cause incorrect results.

3.4.25 –fast

Select options that optimize execution performance.

This option is defined as a particular selection of other options that is subject to change from one release to another, and between compilers. Also, some of the options selected by -fast might not be available on all platforms. Compile with the -dryrun flag to see the expansion of -fast.

-fast provides high performance for certain benchmark applications. However, the particular choice of options may or may not be appropriate for your application. Use -fast as a good starting point for compiling your application for best performance. But additional tuning may still be required. If your program behaves improperly when compiled with -fast, look closely at the individual options that make up -fast and invoke only those appropriate to your program that preserve correct behavior.

Note also that a program compiled with -fast may show good performance and accurate results with some data sets, but not with others. Avoid compiling with -fast those programs that depend on particular properties of floating-point arithmetic.

Because some of the options selected by -fast have linking implications, if you compile and link in separate steps be sure to link with -fast also.

–fast selects the following options:

• The -xtarget=native hardware target. If the program is intended to run on a different target than the compilation machine, follow the -fast with a code–generator option. For example: f95 -fast -xtarget=ultraT2 ...

• The -O5 optimization level option.

• The -depend option analyzes loops for data dependencies and possible restructuring.

• The -libmil option for system–supplied inline expansion templates. For C functions that depend on exception handling, follow -fast by -nolibmil (as in -fast -nolibmil). With -libmil, exceptions cannot be detected with errno or matherr(3m).

• The -fsimple=2 option for aggressive floating–point optimizations.–fsimple=2 is unsuitable if strict IEEE 754 standards compliance is required. See 3.4.36 –fsimple[={1|2|0}].

• The -dalign option to generate double loads and stores for double and quad data in common blocks. Using this option can generate nonstandard Fortran data alignment in common blocks.

• The -xlibmopt option selects optimized math library routines.

• -pad=local inserts padding between local variables, where appropriate, to improve cache usage. (SPARC)

• -xvector=lib transforms certain math library calls within DO loops to single calls to a vectorized library equivalent routine with vector arguments. (SPARC)

• –fns selects non-standard floating-point arithmetic exception handling and gradual underflow. See 3.4.30 –fns[={yes|no}].

• -fround=nearest is selected because —xvector and —xlibmopt require it. (Solaris)

• Trapping on common floating-point exceptions, -ftrap=common, is the enabled with f95.

• -nofstore cancels forcing expressions to have the precision of the result. (x86)

• -xregs=frameptr allows the compiler to use the frame-pointer register as an unallocated callee-saves register. Specify -xregs=no%frameptr after -fast and the frame pointer register will not be used as a general purpose register. (x86)

It is possible to add or subtract from this list by following the -fast option with other options, as in:

f95 -fast -fsimple=1 -xnolibmopt ...

which overrides the -fsimple=2 option and disables the -xlibmopt selected by -fast.

Because -fast invokes -dalign, -fns, -fsimple=2, programs compiled with -fast can result in nonstandard floating-point arithmetic, nonstandard alignment of data, and nonstandard ordering of expression evaluation. These selections might not be appropriate for most programs.

Note that the set of options selected by the -fast flag can change with each compiler release. Invoking the compiler with -dryrun displays the -fast exapansion:

<sparc>%f95 -dryrun -fast |& grep ###
          ###     command line files and options (expanded):
          ### -dryrun -xO5 -xarch=sparcvis2 -xcache=64/32/4:1024/64/4
              -xchip=ultra3i -xdepend=yes -xpad=local -xvector=lib
              -dalign -fsimple=2 -fns=yes -ftrap=common -xlibmil
              -xlibmopt -fround=nearest

3.4.26 –fixed

Specify fixed–format Fortran 95 source input files.

All source files on the command–line will be interpreted as fixed format regardless of filename extension. Normally, f95 interprets only .f files as fixed format, .f95 as free format.

3.4.27 –flags

Synonym for -help.

3.4.28 -fma={none|fused}

(SPARC) Enable automatic generation of floating-point, fused, multiply-add instructions. -fma=none disables generation of these instructions. -fma=fused allows the compiler to attempt to find opportunities to improve the performance of the code by using floating-point, fused, multiply-add instructions. The default is -fma=none.

Minimum requirements are -xarch=sparcfmaf and an optimization level of at least -xO2 for the compiler to generate fused multiply-add instructions. The compiler will mark the binary program if fused multiply-add instructions have been generated to prevent execution of the program on platforms that do not support them.

Fused multiply-adds eliminate the intermediate rounding step between the multiply and the add. Consequently, programs may produce different results when compiled with -fma=fused, although precision will tend to be increased rather than decreased.

3.4.29 –fnonstd

Initialize floating–point hardware to non–standard preferences.

This option is a macro for the combination of the following option flags:

–fns -ftrap=common

Specifying -fnonstd is approximately equivalent to the following two calls at the beginning of a Fortran main program.

i=ieee_handler("set", "common", SIGFPE_ABORT)
call nonstandard_arithmetic()

The nonstandard_arithmetic() routine replaces the obsolete abrupt_underflow() routine of earlier releases.

To be effective, the main program must be compiled with this option.

Using this option initializes the floating-point hardware to:

• Abort (trap) on floating-point exceptions.

• Flush underflow results to zero if it will improve speed, rather than produce a subnormal number as the IEEE standard requires.

See -fns for more information about gradual underflow and subnormal numbers.

The -fnonstd option allows hardware traps to be enabled for floating–point overflow, division by zero, and invalid operation exceptions. These are converted into SIGFPE signals, and if the program has no SIGFPE handler, it terminates with a dump of memory.

For more information, see the ieee_handler(3m) and ieee_functions(3m) man pages, the Numerical Computation Guide, and the Fortran Programming Guide.

3.4.30 –fns[={yes|no}]

Select nonstandard floating–point mode.

The default is the standard floating–point mode (–fns=no). (See the “Floating–Point Arithmetic” chapter of the Fortran Programming Guide.)

Optional use of =yes or =no provides a way of toggling the -fns flag following some other macro flag that includes it, such as -fast. -fns without a value is the same as -fns=yes.

This option flag enables nonstandard floating-point mode when the program begins execution. On SPARC platforms, specifying nonstandard floating-point mode disables “gradual underflow”, causing tiny results to be flushed to zero rather than producing subnormal numbers. It also causes subnormal operands to be silently replaced by zero. On those SPARC systems that do not support gradual underflow and subnormal numbers in hardware, use of this option can significantly improve the performance of some programs.

Where x does not cause total underflow, x is a subnormal number if and only if |x| is in one of the ranges indicated:

See the Numerical Computation Guide for details on subnormal numbers, and the Fortran Programming Guide chapter “Floating–Point Arithmetic” for more information about this and similar options. (Some arithmeticians use the term denormalized number for subnormal number.)

The standard initialization of floating–point preferences is the default:

• IEEE 754 floating–point arithmetic is nonstop (do not abort on exception).

• Underflows are gradual.

On x86 platforms, this option is enabled only for Pentium III and Pentium 4 processors (sse or sse2 instruction sets).

On x86, -fns selects SSE flush-to-zero mode and where available, denormals-are-zero mode. This flag causes subnormal results to be flushed to zero. Where available, this flag also causes subnormal operands to be treated as zero. This flag has no effect on traditional x87 floating-point operations not utilizing the SSE or SSE2 instruction set.

To be effective, the main program must be compiled with this option.

3.4.31 –fpover[={yes|no}]

Detect floating-point overflow in formatted input.

With -fpover=yes specified, the I/O library will detect runtime floating-point overflows in formatted input and return an error condition (1031). The default is no such overflow detection (–fpover=no). -fpover without a value is equivalent to -fpover=yes. Combine with —ftrap to get full diagnostic information.

3.4.32 –fpp

Force preprocessing of input with fpp.

Pass all the input source files listed on the f95 command line through the fpp preprocessor, regardless of file extension. (Normally, only files with .F, .F90, or .F95 extension are automatically preprocessed by fpp.) See also 3.4.156 –xpp={fpp|cpp}.

3.4.33 –fprecision={single|double|extended}

(x86) Initialize non-default floating-point rounding precision mode.

On x86, sets the floating-point precision mode to either single, double, or extended.

With a value of single or double, this flag causes the rounding precision mode to be set to single or double precision respectively at program initiation. With extended, or by default when the -fprecision flag is not specified, the rounding precision mode is initialized to extended precision.

This option is effective only on x86 systems and only if used when compiling the main program.

3.4.34 –free

Specify free–format source input files.

All source files on the command–line will be interpreted as f95 free format regardless of filename extension. Normally, f95 interprets .f files as fixed format, .f95 as free format.

3.4.35 –fround={nearest|tozero|negative|positive}

Set the IEEE rounding mode in effect at startup.

The default is -fround=nearest.

To be effective, compile the main program with this option.

This option sets the IEEE 754 rounding mode that:

• Can be used by the compiler in evaluating constant expressions.

• Is established at runtime during the program initialization.

When the value is tozero, negative, or positive, the option sets the rounding direction to round-to-zero, round-to-negative-infinity, or round-to-positive-infinity, respectively, when the program begins execution. When -fround is not specified, -fround=nearest is used as the default and the rounding direction is round-to-nearest. The meanings are the same as those for the ieee_flags function. (See the “Floating–Point Arithmetic” chapter of the Fortran Programming Guide.)

3.4.36 –fsimple[={1|2|0}]

Select floating–point optimization preferences.

Allow the optimizer to make simplifying assumptions concerning floating–point arithmetic. (See the “Floating–Point Arithmetic” chapter of the Fortran Programming Guide.)

For consistent results, compile all units of a program with the same -fsimple option.

The defaults are:

• Without the -fsimple flag, the compiler defaults to -fsimple=0

• With -fsimple without a value, the compiler uses -fsimple=1

The different floating–point simplification levels are:

–fsimple=0

Permit no simplifying assumptions. Preserve strict IEEE 754 conformance.

–fsimple=1

Allow conservative simplifications. The resulting code does not strictly conform to IEEE 754, but numeric results of most programs are unchanged.

With -fsimple=1, the optimizer can assume the following:

• IEEE 754 default rounding/trapping modes do not change after process initialization.

• Computations producing no visible result other than potential floating point exceptions may be deleted.

• Computations with Infinity or NaNs (“Not a Number”) as operands need not propagate NaNs to their results; for example, x*0 may be replaced by 0.

• Computations do not depend on sign of zero.

With -fsimple=1, the optimizer is not allowed to optimize completely without regard to roundoff or exceptions. In particular, a floating–point computation cannot be replaced by one that produces different results with rounding modes held constant at run time.

–fsimple=2

In addition to —fsimple=1, permit aggressive floating point optimizations. This can cause some programs to produce different numeric results due to changes in the way expressions are evaluated. In particular, the Fortran standard rule requiring compilers to honor explicit parentheses around subexpressions to control expression evaluation order may be broken with -fsimple=2. This could result in numerical rounding differences with programs that depend on this rule.

For example, with -fsimple=2, the compiler may evaluate C-(A-B) as (C-A)+B, breaking the standard’s rule about explicit parentheses, if the resulting code is better optimized. The compiler might also replace repeated computations of x/y with x*z, where z=1/y is computed once and saved in a temporary, to eliminate the costly divide operations.

Programs that depend on particular properties of floating-point arithmetic should not be compiled with -fsimple=2.

Even with -fsimple=2, the optimizer still is not permitted to introduce a floating point exception in a program that otherwise produces none.

–fast selects -fsimple=2.

3.4.37 –fstore

(x86) Force precision of floating-point expressions.

For assignment statements, this option forces all floating-point expressions to the precision of the destination variable. This is the default. However, the -fast option includes -nofstore to disable this option. Follow -fast with -fstore to turn this option back on.

3.4.38 –ftrap=t

Set floating–point trapping mode in effect at startup.

t is a comma–separated list that consists of one or more of the following:

%all, %none, common, [no%]invalid, [no%]overflow, [no%]underflow, [no%]division, [no%]inexact.

-ftrap=common is a macro for -ftrap=invalid,overflow,division.

The f95 default is -ftrap=common. This differs from the C and C++ compiler defaults, which is -ftrap=none.

Sets the IEEE 745 trapping mode in effect at startup but does not install a SIGFPE handler. You can use ieee_handler(3M) or fex_set_handling(3M) to simultaneously enable traps and install a SIGFPE handler. If you specify more than one value, the list is processed sequentially from left to right. The common exceptions, by definition, are invalid, division by zero, and overflow.

Example: -ftrap=%all,no%inexact means set all traps, except inexact.

The meanings for -ftrap=t are the same as for ieee_flags(), except that:

• %all turns on all the trapping modes, and will cause trapping of spurious and expected exceptions. Use common instead.

• %none turns off all trapping modes.

• A no% prefix turns off that specific trapping mode.

To be effective, compile the main program with this option.

For further information, see the “Floating–Point Arithmetic” chapter in the Fortran Programming Guide.

3.4.39 –G

Build a dynamic shared library instead of an executable file.

Direct the linker to build a shared dynamic library. Without -G, the linker builds an executable file. With -G, it builds a dynamic library. Use -o with -G to specify the name of the file to be written. See the Fortran Programming Guide chapter “Libraries” for details.

3.4.40 –g

Compile for debugging and performance analysis.

Produce additional symbol table information for debugging with dbx(1) debugging utility and for performance analysis with the Performance Analyzer.

Although some debugging is possible without specifying -g, the full capabilities of dbx and debugger are only available to those compilation units compiled with -g.

Some capabilities of other options specified along with -g may be limited. See the dbx documentation for details.

To use the full capabilities of the Performance Analyzer, compile with -g. While some performance analysis features do not require -g, you must compile with -g to view annotated source, some function level information, and compiler commentary messages. (See the analyzer(1) man page and the manual Sun Studio Performance Analyzer.)

The commentary messages generated with -g describe the optimizations and transformations the compiler made while compiling your program. The messages, interleaved with the source code, can be displayed by the er_src(1) command.

Note that commentary messages only appear if the compiler actually performed any optimizations. You are more likely to see commentary messages when you request high optimization levels, such as with -xO4, or -fast.

3.4.41 –hname

Specify the name of the generated dynamic shared library.

This option is passed on to the linker. For details, see the Solaris Linker and Libraries Guide, and the Fortran Programming Guide chapter “Libraries.”

The -hname option records the name name to the shared dynamic library being created as the internal name of the library. A space between -h and name is optional (except if the library name is elp, for which the space will be needed). In general, name must be the same as what follows the -o. Use of this option is meaningless without also specifying -G.

Without the -hname option, no internal name is recorded in the library file.

If the library has an internal name, whenever an executable program referencing the library is run the runtime linker will search for a library with the same internal name in any path the linker is searching. With an internal name specified, searching for the library at runtime linking is more flexible. This option can also be used to specify versions of shared libraries.

If there is no internal name of a shared library, then the linker uses a specific path for the shared library file instead.

3.4.42 –help

Display a summary list of compiler options.

See also 3.4.125 –xhelp={readme|flags}.

3.4.43 –Ipath

Add path to the INCLUDE file search path.

Insert the directory path path at the start of the INCLUDE file search path. No space is allowed between -I and path. Invalid directories are ignored with no warning message.

The include file search path is the list of directories searched for INCLUDE files—file names appearing on preprocessor #include directives, or Fortran INCLUDE statements.

Example: Search for INCLUDE files in /usr/app/include:

demo% f95 -I/usr/app/include growth.F

Multiple -Ipath options may appear on the command line. Each adds to the top of the search path list (first path searched).

The search order for relative paths on INCLUDE or #include is:

1. The directory that contains the source file

2. The directories that are named in the -I options

3. The directories in the compiler’s internal default list

4. /usr/include/

To invoke the preprocessor, you must be compiling source files with a .F, .F90, .F95, or .F03 suffix.

3.4.44 -i8

(There is no i8 option.)

Use —xtypemap=integer:64 to specify 8–byte INTEGER with this compiler.

3.4.45 –inline=[%auto][[,][no%]f1,…[no%]fn]

Enable or disable inlining of specified routines.

Request the optimizer to inline the user–written routines appearing in a comma-separated list of function and subroutine names. Prefixing a routine name with no% disables inlining of that routine.

Inlining is an optimization technique whereby the compiler effectively replaces a subprogram reference such as a CALL or function call with the actual subprogram code itself. Inlining often provides the optimizer more opportunities to produce efficient code.

Specify %auto to enable automatic inlining at optimization levels -O4 or -O5. Automatic inlining at these optimization levels is normally turned off when explicit inlining is specified with -inline.

Example: Inline the routines xbar, zbar, vpoint:

demo% f95 -O3 -inline=xbar,zbar,vpoint *.f

Following are the restrictions; no warnings are issued:

• Optimization must be -O3 or greater.

• The source for the routine must be in the file being compiled, unless -xipo or–xcrossfile are also specified.

• The compiler determines if actual inlining is profitable and safe.

The appearance of -inline with -O4 disables the automatic inlining that the compiler would normally perform, unless %auto is also specified. With -O4, the compilers normally try to inline all appropriate user–written subroutines and functions. Adding -inline with -O4 may degrade performance by restricting the optimizer’s inlining to only those routines in the list. In this case, use the %auto suboption to enable automatic inlining at -O4 and -O5.

demo% f95 -O4 -inline=%auto,no%zpoint *.f

In the example above, the user has enabled -O4’s automatic inlining while disabling any possible inlining of the routine zpoint() that the compiler might attempt.

3.4.46 –iorounding[={compatible|processor-defined}]

Set floating-point rounding mode for formatted input/output.

Sets the ROUND= specifier globally for all formatted input/output operations.

With -iorounding=compatible, the value resulting from data conversion is the one closer to the two nearest representations, or the value away from zero if the value is halfway between them.

With -iorounding=processor-defined, the rounding mode is the processor’s default mode. This is the default when -iorounding is not specified.

3.4.47 –Kpic

(Obsolete) Synonym for -pic.

3.4.48 –KPIC

(Obsolete) Synonym for -PIC.

3.4.49 –Lpath

Add path to list of directory paths to search for libraries.

Adds path to the front of the list of object–library search directories. A space between -L and path is optional. This option is passed to the linker. See also 3.4.50 –lx.

While building the executable file, ld(1) searches path for archive libraries (.a files) and shared libraries (.so files). ld searches path before searching the default directories. (See the Fortran Programming Guide chapter “Libraries” for information on library search order.) For the relative order between LD_LIBRARY_PATH and -Lpath, see ld(1).

Specifying /usr/lib or /usr/ccs/lib with -L path may prevent linking the unbundled libm. These directories are searched by default.

Example: Use -Lpath to specify library search directories:

demo% f95 -L./dir1 -L./dir2 any.f

3.4.50 –lx

Add library libx.a to linker’s list of search libraries.

Pass -lx to the linker to specify additional libraries for ld to search for unresolved references. ld links with object library libx. If shared library libx.so is available (and -Bstatic or -dn are not specified), ld uses it, otherwise, ld uses static library libx.a. If it uses a shared library, the name is built in to a.out. No space is allowed between -l and x character strings.

Example: Link with the library libVZY:

demo% f95 any.f -lVZY

Use -lx again to link with more libraries.

Example: Link with the libraries liby and libz:

demo% f95 any.f -ly -lz

See also the “Libraries” chapter in the Fortran Programming Guide for information on library search paths and search order.

3.4.51 –libmil

Inline selected libm library routines for optimization.

There are inline templates for some of the libm library routines. This option selects those inline templates that produce the fastest executable for the floating–point options and platform currently being used.

For more information, see the man pages libm_single(3F) and libm_double(3F)

3.4.52 –loopinfo

Show loop parallelization results.

Show which loops were and were not parallelized with the–autopar option.

–loopinfo displays a list of messages on standard error:

demo% f95 -c -fast -autopar -loopinfo shalow.f
...
"shalow.f", line 172: PARALLELIZED, and serial version generated
"shalow.f", line 173: not parallelized, not profitable
"shalow.f", line 181: PARALLELIZED, fused
"shalow.f", line 182: not parallelized, not profitable
...
...etc

3.4.53 –Mpath

Specify MODULE directory, archive, or file.

Look in path for Fortran modules referenced in the current compilation. This path is searched in addition to the current directory.

path can specify a directory, .a archive file of precompiled module files, or a .mod precompiled module file. The compiler determines the type of the file by examining its contents.

An archive .a file must be explicitly specified on a -M option flag to be searched for modules. The compiler will not search archive files by default.

Only .mod files with the same names as the MODULE names appearing on USE statements will be searched. For example, the statement USE ME causes the compiler to look only for the module file me.mod

When searching for modules, the compiler gives higher priority to the directory where the module files are being written. This is controlled by the -moddir compiler option, or the MODDIR environment variable. When neither are specified, the default write-directory is the current directory. When both are specified, the write-directory is the path specified by the -moddir flag.

This means that if only the -M flag appears, the current directory will be searched for modules first before any object listed on the -M flag. To emulate the behavior of previous releases, use:

-moddir=empty-dir -Mdir -M

where empty-dir is the path to an empty directory.

A space between the -M and the path is allowed. For example, -M /home/siri/PK15/Modules

On Solaris, if the path identifies a regular file that is not an archive or a module file, the compiler passes the option to the linker, ld, which will treat it as a linker mapfile. This feature is provided as a convenience similar to the C and C++ compilers.

See 4.9 Module Files for more information about modules in Fortran.

3.4.54 –m32 | –m64

Specify memory model for compiled binary object.

Use -m32 to create 32-bit executables and shared libraries. Use -m64 to create 64-bit executables and shared libraries.

The ILP32 memory model (32-bit int, long, pointer data types) is the default on all Solaris platforms and on Linux platforms that are not 64-bit enabled. The LP64 memory model (64-bit long, pointer data types) is the default on Linux platforms that are 64-bit enabled. -m64 is permitted only on platforms that are enabled for the LP64 model.

Object files or libraries compiled with -m32 cannot be linked with object files or libraries compiled with -m64.

When compiling applications with large amounts of static data using -m64, -xmodel=medium may also be required.

Be aware that some Linux platforms do not support the medium model.

Note that in previous compiler releases, the memory model, ILP32 or LP64, was implied by the choice of the instruction set with -xarch. Starting with the Sun Studio 12 compilers, this is no longer the case. On most platforms, just adding -m64 to the command line is sufficient to create 64-bit objects.

On Solaris, -m32 is the default. On Linux systems supporting 64-bit programs, -m64 -xarch=sse2 is the default.

3.4.55 –moddir=path

Specify where the compiler will write compiled .mod MODULE files.

The compiler will write the .mod MODULE information files it compiles in the directory specified by path. The directory path can also be specified with the MODDIR environment variable. If both are specified, this option flag takes precedence.

The compiler uses the current directory as the default for writing .mod files.

See 4.9 Module Files for more information about modules in Fortran.

3.4.56 –mt

Require linking to thread–safe libraries.

If you do your own low–level thread management (for example, by calling the libthread library), compiling with -mt prevents conflicts.

Use -mt if you mix Fortran with multithreaded C code that calls the libthread library. See also the Solaris Multithreaded Programming Guide.

–mt is implied automatically when compiling with the -autopar option.

Note the following:

• A function subprogram that does I/O should not itself be referenced as part of an I/O statement. Such recursive I/O may cause the program to deadlock with -mt.

• In general, do not compile your own multithreaded code with -autopar. The compiler-generated calls to the threads library and the program’s own calls may conflict, causing unexpected results.

• On a single–processor system, performance may be degraded with the -mt option.

3.4.57 –native

(Obsolete) Optimize performance for the host system.

This option is a synonym for -xtarget=native, which is preferred. The -fast option sets -xtarget=native.

3.4.58 –noautopar

Disables automatic parallelization invoked by -autopar earlier on the command line.

3.4.59 –nodepend

(SPARC) Cancel any -depend appearing earlier on the command line.

3.4.60 -nofstore

(x86) Cancel -fstore on command line.

The compiler default is -fstore. -fast includes -nofstore.

3.4.61 –nolib

Disable linking with system libraries.

Do not automatically link with any system or language library; that is do not pass any default -lx options on to ld. The normal behavior is to link system libraries into the executables automatically, without the user specifying them on the command line.

The -nolib option makes it easier to link one of these libraries statically. The system and language libraries are required for final execution. It is your responsibility to link them in manually. This option provides you with complete control.

Link libm statically and libc dynamically with f95:

demo% f95 -nolib any.f95 -Bstatic -lm -Bdynamic -lc

The order for the -lx options is important. Follow the order shown in the examples.

3.4.62 –nolibmil

Cancel -libmil on command line.

Use this option after the -fast option to disable inlining of libm math routines:

demo% f95 -fast -nolibmil …

3.4.63 –noreduction

Disable -reduction on command line.

This option disables -reduction.

3.4.64 –norunpath

Do not build a runtime shared library search path into the executable.

The compiler normally builds into an executable a path that tells the runtime linker where to find the shared libraries it will need. The path is installation dependent. The -norunpath option prevents that path from being built in to the executable.

This option is helpful when libraries have been installed in some nonstandard location, and you do not wish to make the loader search down those paths when the executable is run at another site. Compare with -Rpaths.

See the Fortran Programming Guide chapter on “Libraries” for more information.

3.4.65 –O[n]

Specify optimization level.

n can be 1, 2, 3, 4, or 5. No space is allowed between -O and n.

If -O[n] is not specified, only a very basic level of optimization limited to local common subexpression elimination and dead code analysis is performed. A program’s performance may be significantly improved when compiled with an optimization level than without optimization. Use of -O (which sets -O3) or -fast (which sets -O5) is recommended for most programs.

Each -On level includes the optimizations performed at the levels below it. Generally, the higher the level of optimization a program is compiled with, the better runtime performance obtained. However, higher optimization levels may result in increased compilation time and larger executable files.

Debugging with -g does not suppress -On, but -On limits -g in certain ways; see the dbx documentation.

The -O3 and -O4 options reduce the utility of debugging such that you cannot display variables from dbx, but you can still use the dbx where command to get a symbolic traceback.

If the optimizer runs out of memory, it attempts to proceed over again at a lower level of optimization, resuming compilation of subsequent routines at the original level.

For details on optimization, see the Fortran Programming Guide chapters “Performance Profiling” and “Performance and Optimization.”

3.4.66 –O

This is equivalent to -O3.

3.4.67 –O1

Provides a minimum of statement–level optimizations.

Use if higher levels result in excessive compilation time, or exceed available swap space.

3.4.68 –O2

Enables basic block level optimizations.

This level usually gives the smallest code size. (See also -xspace.)

–O3 is preferred over -O2 unless -O3 results in unreasonably long compilation time, exceeds swap space, or generates excessively large executable files.

3.4.69 –O3

Adds loop unrolling and global optimizations at the function level. Adds -depend automatically.

Usually -O3 generates larger executable files.

3.4.70 –O4

Adds automatic inlining of routines contained in the same file.

Usually -O4 generates larger executable files due to inlining.

The -g option suppresses the -O4 automatic inlining described above.–xcrossfile increases the scope of inlining with -O4.

3.4.71 –O5

Attempt aggressive optimizations.

Suitable only for that small fraction of a program that uses the largest fraction of compute time. -O5’s optimization algorithms take more compilation time, and may also degrade performance when applied to too large a fraction of the source program.

Optimization at this level is more likely to improve performance if done with profile feedback. See -xprofile=p.

3.4.72 –o name

Specify the name of the executable file to be written.

There must be a blank between -o and name. Without this option, the default is to write the executable file to a.out. When used with -c, -o specifies the target .o object file; with -G it specifies the target .so library file.

3.4.73 –onetrip

Enable one trip DO loops.

Compile DO loops so that they are executed at least once. DO loops in standard Fortran are not performed at all if the upper limit is smaller than the lower limit, unlike some legacy implementations of Fortran.

3.4.74 –openmp

Synonym for -xopenmp.

3.4.75 –p

(Obsolete) Compile for profiling with the prof profiler.

Prepare object files for profiling, see prof (1). If you compile and link in separate steps, and also compile with the -p option, then be sure to link with the -p option. -p with prof is provided mostly for compatibility with older systems. -pg profiling with gprof is possibly a better alternative. See the Fortran Programming Guide chapter on Performance Profiling for details.

3.4.76 –pad[=p]

Insert padding for efficient use of cache.

This option inserts padding between arrays or character variables, if they are static local and not initialized, or if they are in common blocks. The extra padding positions the data to make better use of cache. In either case, the arrays or character variables can not be equivalenced.

p, if present, must be either %none or either (or both) local or common:

If both local and common are specified, they can appear in any order.

Defaults for -pad:

• The compiler does no padding by default.

• Specifying -pad, but without a value is equivalent to -pad=local,common.

The -pad[=p] option applies to items that satisfy the following criteria:

• The items are arrays or character variables

• The items are static local or in common blocks

For a definition of local or static variables, see 3.4.91 –stackvar.

The program must conform to the following restrictions:

• Neither the arrays nor the character strings are equivalenced

• If -pad=common is specified for compiling a file that references a common block, it must be specified when compiling all files that reference that common block. The option changes the spacing of variables within the common block. If one program unit is compiled with the option and another is not, references to what should be the same location within the common block might reference different locations.

• If -pad=common is specified, the declarations of common block variables in different program units must be the same except for the names of the variables.The amount of padding inserted between variables in a common block depends on the declarations of those variables. If the variables differ in size or rank in different program units, even within the same file, the locations of the variables might not be the same.

• If -pad=common is specified, EQUIVALENCE declarations involving common block variables are flagged with a warning message and the block is not padded.

• Avoid overindexing arrays in common blocks with -pad=common specified. The altered positioning of adjacent data in a padded common block will cause overindexing to fail in unpredictable ways.

It is the programmer’s responsibility to make sure that common blocks are compiled consistently when -pad is used. Common blocks appearing in different program units that are compiled inconsistently with -pad=common will cause errors. Compiling with -Xlist will report when common blocks with the same name have different lengths in different program units.

3.4.77 –pg

Compile for profiling with the gprof profiler.

Compile self–profiling code in the manner of -p, but invoke a runtime recording mechanism that keeps more extensive statistics and produces a gmon.out file when the program terminates normally. Generate an execution profile by running gprof. See the gprof(1) man page and the Fortran Programming Guide for details.

Library options must be after the source and .o files (–pg libraries are static).

There is no advantage compiling with -xprofile if you specify -pg. These two features do not prepare or use data provided by the other.

Profiles generated by using prof(1) or gprof(1) on 64 bit Solaris platforms or just gprof on 32 bit Solaris platforms include approximate user CPU times. These times are derived from PC sample data (see pcsample(2)) for routines in the main executable and routines in shared libraries specified as linker arguments when the executable is linked. Other shared libraries (libraries opened after process startup using dlopen(3DL)) are not profiled.

On 32 bit Solaris systems, profiles generated using prof(1) are limited to routines in the executable. 32 bit shared libraries can be profiled by linking the executable with -pg and using gprof(1).

The Solaris 10 software does not include system libraries compiled with -p. As a result, profiles collected on Solaris 10 platforms do not include call counts for system library routines.

The compiler options -p, -pg, or -xpg should not be used to compile multi-threaded programs, because the runtime support for these options is not thread-safe. If a program that uses multiple threads is compiled with these options invalid results or a segmentation fault could occur at runtime.

If you compile and link in separate steps, and you compile with -pg, then be sure to link with -pg.

3.4.78 –pic

Compile position–independent code for shared library.

On SPARC, –pic is equivalent to -xcode=pic13. See 3.4.117 –xcode=keyword for more information on position-indepented code.

On x86, produces position-independent code. Use this option to compile source files when building a shared library. Each reference to a global datum is generated as a dereference of a pointer in the global offset table. Each function call is generated in pc-relative addressing mode through a procedure linkage table.

3.4.79 –PIC

Compile position–independent code with 32-bit addresses.

On SPARC, –PIC is equivalent to -xcode=pic32. See 3.4.117 –xcode=keyword for more information about position-independent code.

On x86, —PIC is equivalent to —pic.

3.4.80 –Qoption pr ls

Pass the suboption list ls to the compilation phase pr.

There must be blanks separating Qoption, pr, and ls. The Q can be uppercase or lowercase. The list is a comma–delimited list of suboptions, with no blanks within the list. Each suboption must be appropriate for that program phase, and can begin with a minus sign.

This option is provided primarily for debugging the internals of the compiler by support staff. Use the LD_OPTIONS environment variable to pass options to the linker. See the chapter on linking and libraries in the Fortran Programming Guide.

3.4.81 –qp

Synonym for -p.

3.4.82 –R ls

Build dynamic library search paths into the executable file.

With this option, the linker, ld(1), stores a list of dynamic library search paths into the executable file.

ls is a colon–separated list of directories for library search paths. The blank between -R and ls is optional.

Multiple instances of this option are concatenated together, with each list separated by a colon.

The list is used at runtime by the runtime linker, ld.so. At runtime, dynamic libraries in the listed paths are scanned to satisfy any unresolved references.

Use this option to let users run shippable executables without a special path option to find needed dynamic libraries.

Building an executable file using -Rpaths adds directory paths to a default path that is always searched last.

For more information, see the “Libraries” chapter in the Fortran Programming Guide, and the Solaris Linker and Libraries Guide.

3.4.83 –r8const

Promote single-precision constants to REAL*8 constants.

All single-precision REAL constants are promoted to REAL*8. Double-precision (REAL*8) constants are not changed. This option only applies to constants. To promote both constants and variables, see 3.4.173 –xtypemap=spec.

Use this option flag carefully. It could cause interface problems when a subroutine or function expecting a REAL*4 argument is called with a REAL*4 constant that gets promoted to REAL*8. It could also cause problems with programs reading unformatted data files written by an unformatted write with REAL*4 constants on the I/O list.

3.4.84 -recl=a[,b]

Set default output record length.

Set the default record length (in characters) for either or both preconnected units output (standard output) and error (standard error). This option must be specified using one of the following forms:

• -recl=out:N

• -recl=error:N

• —recl=out:N1,error:N2

• -recl=error:N1,out:N2

• -recl=all:N

where N, N1, N2 are all positive integers in the range from 72 to 2147483646. out refers to standard output, error to standard error, and all sets the default record length to both. The default is -recl=all:80. This option is only effective if the program being compiled has a Fortran main program.

3.4.85 –reduction

Recognize reduction operations in loops.

Analyze loops for reduction operations during automatic parallelization. There is potential for roundoff error with the reduction.

A reduction operation accumulates the elements of an array into a single scalar value. For example, summing the elements of a vector is a typical reduction operation. Although these operations violate the criteria for parallelizability, the compiler can recognize them and parallelize them as special cases when -reduction is specified. See the Fortran Programming Guide chapter “Parallelization” for information on reduction operations recognized by the compilers.

This option is usable only with the automatic parallelization option —autopar. It is ignored otherwise. Explicitly parallelized loops are not analyzed for reduction operations.

3.4.86 –S

Compile and only generate assembly code.

Compile the named programs and leave the assembly–language output on corresponding files suffixed with .s. No .o file is created.

3.4.87 –s

Strip the symbol table out of the executable file.

This option makes the executable file smaller and more difficult to reverse engineer. However, this option inhibits debugging with dbx or other tools, and overrides -g.

3.4.88 –sb

(Obsolete-this option is ignored)

3.4.89 –sbfast

(Obsolete — this option is ignored.)

3.4.90 –silent

(Obsolete) Suppress compiler messages.

Normally, the f95 compiler does not issue messages, other than error diagnostics, during compilation. This option flag is provided for compatibility with the legacy f77 compiler, and its use is redundant except with the -f77 compatibility flag.

3.4.91 –stackvar

Allocate local variables on the stack whenever possible.

This option makes writing recursive and re-entrant code easier and provides the optimizer more freedom when parallelizing loops.

Use of -stackvar is recommended with any of the parallelization options.

Local variables are variables that are not dummy arguments, COMMON variables, variables inherited from an outer scope, or module variables made accessible by a USE statement.

With -stackvar in effect, local variables are allocated on the stack unless they have the attributes SAVE or STATIC. Note that explicitly initialized variables are implicitly declared with the SAVE attribute. A structure variable that is not explicitly initialized but some of whose components are initialized is, by default, not implicitly declared SAVE. Also, variables equivalenced with variables that have the SAVE or STATIC attribute are implicitly SAVE or STATIC.

A statically allocated variable is implicitly initialized to zero unless the program explicitly specifies an initial value for it. Variables allocated on the stack are not implicitly initialized except that components of structure variables can be initialized by default.

Putting large arrays onto the stack with -stackvar can overflow the stack causing segmentation faults. Increasing the stack size may be required.

The initial thread executing the program has a main stack, while each helper thread of a multithreaded program has its own thread stack.

The default size of the main stack is about 8 Megabytes. The default thread stack size is 4 Megabytes on 32–bit systems, 8 Megabytes on 64–bit systems. The limit command (with no parameters) shows the current main stack size. If you get a segmentation fault using -stackvar, try increasing the main and thread stack sizes.

Example: Show the current main stack size:

demo% limit
cputime         unlimited
filesize        unlimited
datasize        523256 kbytes
stacksize       8192 kbytes      <–––
coredumpsize    unlimited
descriptors     64
memorysize      unlimited
demo%

Example: Set the main stack size to 64 Megabytes:

demo% limit stacksize 65536

Example: Set each thread stack size to 8 Megabytes:

demo% setenv STACKSIZE 8192

You can set the stack size to be used by each slave thread by giving the STACKSIZE environment variable a value (in Kilobytes):

% setenv STACKSIZE 8192

sets the stack size for each slave thread to 8 Mb.

The STACKSIZE environment variable also accepts numerical values with a suffix of either B, K, M, or G for bytes, kilobytes, megabytes, or gigabytes respectively. The default is kilobytes.

Note that the STACKSIZE environment variable affects only programs compiled with the —xopenmp or —xautopar options, and has no affect on programs using the pthreads interface on Solaris systems.

For further information of the use of -stackvar with parallelization, see the “Parallelization” chapter in the Fortran Programming Guide. See csh(1) for details on the limit command.

Compile with -xcheck=stkovf to enable runtime checking for stack overflow situations. See 3.4.115 –xcheck=keyword.

3.4.92 –stop_status[={yes|no}]

Permit STOP statement to return an integer status value.

The default is -stop_status=no.

With -stop_status=yes, a STOP statement may contain an integer constant. That value will be passed to the environment as the program terminates:

STOP 123

The value must be in the range 0 to 255. Larger values are truncated and a run–time message issued. Note that

STOP ”stop string’

is still accepted and returns a status value of 0 to the environment, although a compiler warning message will be issued.

The environment status variable is $status for the C shell csh, and $? for the Bourne and Korn shells, sh and ksh.

3.4.93 –temp=dir

Define directory for temporary files.

Set directory for temporary files used by the compiler to be dir. No space is allowed within this option string. Without this option, the files are placed in the /tmp directory.

This option takes precedence over the value of the TMPDIR environment variable.

3.4.94 –time

Time each compilation phase.

The time spent and resources used in each compiler pass is displayed.

3.4.95 –U

Recognize upper and lower case in source files.

Do not treat uppercase letters as equivalent to lowercase. The default is to treat uppercase as lowercase except within character–string constants. With this option, the compiler treats Delta, DELTA, and delta as different symbols. Calls to intrinsic functions are not affected by this option.

Portability and mixing Fortran with other languages may require use of -U. See the Fortran Programming Guide chapter on porting programs to Sun Studio Fortran.

3.4.96 -Uname

Undefine preprocessor macro name.

This option applies only to source files that invoke the fpp or cpp pre-processor. It removes any initial definition of the preprocessor macro name created by -Dname on the same command line, including those implicitly placed there by the command-line driver, regardless of the order the options appear. It has no effect on any macro definitions in source files. Multiple -Uname flags can appear on the command line. There must be no space between -U and the macro name.

3.4.97 –u

Report undeclared variables.

Make the default type for all variables be undeclared rather than using Fortran implicit typing, as if IMPLICIT NONE appeared in each compilation unit. This option warns of undeclared variables, and does not override any IMPLICIT statements or explicit type statements.

3.4.98 –unroll=n

Enable unrolling of DO loops where possible.

n is a positive integer. The choices are:

• n=1 inhibits all loop unrolling.

• n>1 suggests to the optimizer that it attempt to unroll loops n times.

Loop unrolling generally improves performance, but will increase the size of the executable file. For more information on this and other compiler optimizations, see the “Performance and Optimization” chapter in the Fortran Programming Guide. See also 2.3.1.3 The UNROLL Directive.

3.4.99 –use=list

Specify implicit USE modules.

list is a comma-separated list of module names or module file names.

Compiling with -use=module_name has the effect of adding a USE module_name statement to each subprogram or module being compiled. Compiling with -use=module_file_name has the effect of adding a USE module_name for each of the modules contained in the specified file.

See 4.9 Module Files for more information about modules in Fortran.

3.4.100 –V

Show name and version of each compiler pass.

This option prints the name and version of each pass as the compiler executes.

This information may be helpful when discussing problems with Sun service engineers.

3.4.101 –v

Verbose mode -show details of each compiler pass.

Like -V, shows the name of each pass as the compiler executes, and details the options, macro flag expansions, and environment variables used by the driver.

3.4.102 -vax=keywords

Specify choice of VAX VMS Fortran extensions enabled.

The keywords specifier must be one of the following suboptions or a comma-delimited list of a selection of these.

Sub-options can be individually selected or turned off by preceeding with no%.

Example:

-vax=debug,rsize,no%blank_zero

3.4.103 –vpara

Show verbose parallelization messages.

As the compiler analyzes loops explicitly marked for parallelization with directives, it issues warning messages about certain data dependencies it detects; but the loop will still be parallelized.

Use with -xopenmp and OpenMP API directives.

Warnings are issued with the compiler detects the following situations:

• Problematic use of OpenMP data sharing attributes clauses, such as declaring a variable shared whose accesses in an OpenMP parallel region may cause data race, or declaring a variable private whose value in a parallel region is used after the parallel region.

No warnings appear if all parallelization directives are processed without issues.

Sun Studio compilers support the OpenMP API parallelization model. Consequently, legacy C$MIC parallelization directives are deprecated and ignored. See the OpenMP API User’s Guide for information on migrating to the OpenMP API.

3.4.104 –w[n]

Show or suppress warning messages.

This option shows or suppresses most warning messages. However, if one option overrides all or part of an option earlier on the command line, you do get a warning.

n may be 0, 1, 2 ,3, or 4.

-w0 shows just error messages. This is equivalent to -w. -w1 shows errors and warnings. This is the default without -w.-w2 shows errors, warnings, and cautions.-w3 shows errors, warnings, cautions, and notes.-w4 shows errors, warnings, cautions, notes, and comments.

3.4.105 –Xlist[x]

(Solaris only) Produce listings and do global program checking (GPC).

Use this option to find potential programming bugs. It invokes an extra compiler pass to check for consistency in subprogram call arguments, common blocks, and parameters, across the global program. The option also generates a line–numbered listing of the source code, including a cross reference table. The error messages issued by the -Xlist options are advisory warnings and do not prevent the program from being compiled and linked.

Be sure to correct all syntax errors in the source code before compiling with -Xlist. Unpredictable reports may result when run on a source code with syntax errors.

Example: Check across routines for consistency:

 demo% f95 -Xlist  fil.f

The above example writes the following to the output file fil.lst:

• A line–numbered source listing (default)

• Error messages (embedded in the listing) for inconsistencies across routines

• A cross reference table of the identifiers (default)

By default, the listings are written to the file name.lst, where name is taken from the first listed source file on the command line.

A number of sub–options provide further flexibility in the selection of actions. These are specified by suffixes to the main -Xlist option, as shown in the following table

See the Fortran Programming Guide chapter “Program Analysis and Debugging” for details.

This option is not available on Linux systems.

3.4.106 –xa

Synonym for -a.

3.4.107 -xaddr32[={yes|no}]

(x86/x64 only) The -xaddr32=yes compilation flag restricts the resulting executable or shared object to a 32-bit address space.

An executable that is compiled in this manner results in the creation of a process that is restricted to a 32-bit address space. When -xaddr32=no is specified a usual 64 bit binary is produced. If the -xaddr32 option is not specified, -xaddr32=no is assumed. If only -xaddr32 is specified -xaddr32=yes is assumed.

This option is only applicable to -m64 compilations and only on Solaris platforms supporting SF1_SUNW_ADDR32 software capability. Since Linux kernel does not support address space limitation this option is not available on Linux. The -xaddr32 option is ignored on Linux.

When linking, if a single object file was compiled with -xaddr32=yes the whole output file is assumed to be compiled with -xaddr32=yes. A shared object that is restricted to a 32-bit address space must be loaded by a process that executes within a restricted 32-bit mode address space. For more information refer to the SF1_SUNW_ADDR32 software capabilities definition, described in the Linker and Libraries Guide.

3.4.108 –xalias[=keywords]

Specify degree of aliasing to be assumed by the compiler.

Some non-standard programming techniques can introduce situations that interfere with the compiler’s optimization strategies. The use of overindexing, pointers, and passing global or non-unique variables as subprogram arguments, can introduce ambiguous aliasing situations that could result code that does not work as expected.

Use the -xalias flag to inform the compiler about the degree to which the program deviates from the aliasing requirements of the Fortran standard.

The flag may appear with or without a list of keywords. The keywords list is comma-separated, and each keyword indicates an aliasing situation present in the program.

Each keyword may be prefixed by no% to indicate an aliasing type that is not present.

The aliasing keywords are:

Specifying -xalias without a list gives the best performance for most programs that do not violate Fortran aliasing rules, and corresponds to:

no%dummy,no%craypointer,no%actual,no%overindex,no%ftnpointer

To be effective, -xalias should be used when compiling with optimization levels -xO3 and higher.

The compiler default, with no -xalias flag specified, assumes that the program conforms to the Fortran standard except for Cray pointers:

no%dummy,craypointer,no%actual,no%overindex,no%ftnpointer

Examples of various aliasing situations and how to specify them with -xalias are given in the Porting chapter of the Fortran Programming Guide.

3.4.109 -xannotate[={yes|no}]

(Solaris Only) Instructs the compiler to create binaries that can later be transformed by binary modification tools like binopt(1).

Future binary analysis, code coverage and memory error detection tools will also work with binaries built with this option.

Use the -xannotate=no option to prevent the modification of the binary file by these tools. The -xannotate=yes option must be used with optimization level -xO1 or higher to be effective, and it is only effective on systems with the new linker support library interface - ld_open(). If the compiler is used on a system without this linker interface (for example Solaris 9 and early versions of Solaris 10), it silently will revert to -xannotate=no.

The default is -xannotate=yes, but if either of the above conditions is not met, the default reverts to -xannotate=no.

This option is not available on Linux systems.

3.4.110 –xarch=isa

Specify instruction set architecture (ISA).

Architectures that are accepted by -xarch keyword isa are shown in Table 3–11:

Note that although -xarch can be used alone, it is part of the expansion of the –xtarget option and may be used to override the -xarch value that is set by a specific -xtarget option. For example:

% f95 -xtarget=ultra2 -xarch=sparcfmaf ...

overrides the -xarch set by -xtarget=ultra2

This option limits the code generated by the compiler to the instructions of the specified instruction set architecture by allowing only the specified set of instructions. This option does not guarantee use of any target–specific instructions.

If this option is used with optimization, the appropriate choice can provide good performance of the executable on the specified architecture. An inappropriate choice results in a binary program that is not executable on the intended target platform.

Note the following:

• Legacy 32–bit SPARC instruction set architectures V7 and V8 imply —m32 and cannot be combined with —m64.

• Object binary files (.o) compiled with sparc and sparcvis can be linked and can execute together, but will run only on a sparcvis—compatible platform.

• Object binary files (.o) compiled with sparc, sparcvis, and sparcvis2 can be linked and can execute together, but will run only on a sparcvis2–compatible platform.

For any particular choice, the generated executable may run much more slowly on earlier architectures. Also, although quad-precision (REAL*16 and long double) floating-point instructions are available in many of these instruction set architectures, the compiler does not use these instructions in the code it generates.

The default when -xarch is not specified is generic.

Table 3–12 gives details for each of the -xarch keywords on SPARC platforms.

Table 3–13 details each of the -xarch keywords on x86 platforms. The default on x86 is generic (or generic64 if —m64 is specified) if -xarch is not specified.

3.4.110.1 Special Cautions for x86/x64 Platforms:

There are some important considerations when compiling for x86 Solaris platforms.

• Programs compiled with -xarch set to sse, sse2, sse2a, or sse3 and beyond must be run on platforms supporting these features and extensions..

• OS releases starting with Solaris 9 4/04 are SSE/SSE2-enabled on Pentium 4-compatible platforms. Earlier versions of Solaris OS are not SSE/SSE2- enabled.

• If you compile and link in separate steps, always link using the compiler and with same -xarch setting to ensure that the correct startup routine is linked.

• Arithmetic results on x86 may differ from results on SPARC due to the x86 80-byte floating-point registers. To minimize these differences, use the -fstore option or compile with -xarch=sse2 if the hardware supports SSE2.

• Starting with Sun Studio 11 and the Solaris 10 OS, program binaries compiled and built using these specialized -xarch hardware flags are verified that they are being run on the appropriate platform.

• On systems prior to Solaris 10, no verification is done and it is the user’s responsibility to ensure objects built using these flags are deployed on suitable hardware.

• Running programs compiled with these -xarch options on platforms that are not enabled with the appropriate features or instruction set extensions could result in segmentation faults or incorrect results occurring without any explicit warning messages.

• This warning extends also to programs that employ .il inline assembly language functions or __asm() assembler code that utilize SSE, SSE2, SSE2a, and SSE3 instructions and extensions.

3.4.111 –xassume_control[=keywords]

Set parameters to control ASSUME pragmas.

Use this flag to control the way the compiler handles ASSUME pragmas in the source code.

The ASSUME pragmas provide a way for the programmer to assert special information that the compiler can use for better optimization. These assertions may be qualified with a probability value. Those with a probability of 0 or 1 are marked as certain; otherwise they are considered non-certain.

You can also assert, with a probability or certainty, the trip count of an upcoming DO loop, or that an upcoming branch will be taken.

See 2.3.1.8 The ASSUME Directives, for a description of the ASSUME pragmas recognized by the f95 compiler.

The keywords on the -xassume_control option can be a single suboption keyword or a comma-separated list of keywords. The keyword suboptions recognized are:

The compiler default is

-xassume_control=optimize

This means that the compiler recognizes ASSUME pragmas and they will affect optimization, but no checking is done.

If specified without parameters, -xassume_control implies

-xassume_control=check,fatal

In this case the compiler accepts and checks all certain ASSUME pragmas, but they do not affect optimization. Assertions that are invalid cause the program to terminate.

3.4.112 –xautopar

Synonym for -autopar.

3.4.113 –xbinopt={prepare | off}

(SPARC) Prepare binary for post-compilation optimization.

The compiled binary file is enabled for later optimizations, transformations, and analysis by binopt(1). This option may be used when building executables or shared objects, and it must be used with an optimization level of -O1 or higher to be effective.

There will be a modest increase in the size of the binary file when built with this option, on the order of 5%.

If you compile and link in separate steps, -xbinopt must appear on both the compile and link steps.

If not all the source code for an application is compiled with -xbinopt, the -xbinopt flag should still appear on the final link step that builds the program binary, as shown below:

example% f95 -0 program -xbinopt=prepare a.o b.o c.f95

Only code compiled with -xbinopt can be optimized by binopt(1).

The default is -xbinopt=off.

3.4.114 –xcache=c

Define cache properties for the optimizer.

c must be one of the following:

• generic

• native

• s1/l1/a1[/t1]

• s1/l1/a1[/t1]:s2/l2/a2[/t2]

• s1/l1/a1[/t1]:s2/l2/a2[/t2]:s3/l3/a3[/t3]

The si/li/ai/ti are defined as follows:

si The size of the data cache at level i, in kilobytesli The line size of the data cache at level i, in bytesai The associativity of the data cache at level iti The number of hardware threads sharing the cache at level i (optional).

This option specifies the cache properties that the optimizer can use. It does not guarantee that any particular cache property is used.

Although this option can be used alone, it is part of the expansion of the –xtarget option; it is provided to allow overriding an -xcache value implied by a specific -xtarget option.

Example: -xcache=16/32/4:1024/32/1 specifies the following:

A Level 1 cache has: 16K bytes, 32 byte line size, 4–way associativity.

A Level 2 cache has: 1024K bytes, 32 byte line size, direct mapping associativity.

3.4.115 –xcheck=keyword

Generate special runtime checks and initializations.

The keyword must be one of the following:

Stack overflows, especially in multithreaded applications with large arrays allocated on the stack, can cause silent data corruption in neighboring thread stacks. Compile all routines with -xcheck=stkovf if stack overflow is suspected. But note that compiling with this flag does not guarantee that all stack overflow situations will be detected since they could occur in routines not compiled with this flag.

3.4.116 –xchip=c

Specify target processor for the optimizer.

This option specifies timing properties by specifying the target processor.

Although this option can be used alone, it is part of the expansion of the –xtarget option; it is provided to allow overriding a -xchip value implied by the a specific -xtarget option.

Some effects of -xchip=c are:

• Instruction scheduling

• The way branches are compiled

• Choice between semantically equivalent alternatives

The following tables list the valid -xchip processor name values:

On x86 platforms: the -xchip values are pentium, pentium_pro, pentium3, pentium4, generic, opteron, core2, penryn, nehalem, amdfam10, and native.

3.4.117 –xcode=keyword

(SPARC) Specify code address space on SPARC platforms.

The values for keyword are:

The defaults for not specifying -xcode=keyword explicitly are:

–xcode=abs32 on 32–bit platforms.–xcode=abs44 on 64–bit platforms.

3.4.117.1 Position-Independent Code:

Use -xcode=pic13 or -xcode=pic32 when creating dynamic shared libraries to improve runtime performance.

While the code within a dynamic executable is usually tied to a fixed address in memory, position-independent code can be loaded anywhere in the address space of the process.

When you use position-independent code, relocatable references are generated as an indirect reference through a global offset table. Frequently accessed items in a shared object will benefit from compiling with -xcode=pic13 or -xcode=pic32 by not requiring the large number of relocations imposed by code that is not position-independent.

The size of the global offset table is limited to 8Kb.

There are two nominal performance costs with -xcode={pic13|pic32} :

• A routine compiled with either -xcode=pic13 or -xcode=pic32 executes a few extra instructions upon entry to set a register to point at the global offset table used for accessing a shared library’s global or static variables.

• Each access to a global or static variable involves an extra indirect memory reference through the global offset table. If the compile is done with pic32, there are two additional instructions per global and static memory reference.

When considering the above costs, remember that the use of -xcode=pic13 or -xcode=pic32 can significantly reduce system memory requirements, due to the effect of library code sharing. Every page of code in a shared library compiled -xcode=pic13 or -xcode=pic32 can be shared by every process that uses the library. If a page of code in a shared library contains even a single non-pic (that is, absolute) memory reference, the page becomes nonsharable, and a copy of the page must be created each time a program using the library is executed.

The easiest way to tell whether or not a .o file has been compiled with -xcode=pic13 or -xcode=pic32 is with the nm command:

nm file.o | grep _GLOBAL_OFFSET_TABLE_

A .o file containing position-independent code will contain an unresolved external reference to _GLOBAL_OFFSET_TABLE_ as marked by the letter U.

To determine whether to use -xcode=pic13 or -xcode=pic32, check the size of the Global Offset Table (GOT) by using elfdump -c (see the elfdump(1) man page for more information) and for the section header, sh_name: .got. The sh_size value is the size of the GOT. If the GOT is less than 8,192 bytes, specify -xcode=pic13, otherwise specify -xcode=pic32.

In general, use the following guidelines to determine how you should use -xcode:

• If you are building an executable you should not use -xcode=pic13 or -xcode=pic32.

• If you are building an archive library only for linking into executables you should not use -xcode=pic13 or -xcode=pic32.

• If you are building a shared library, start with -xcode=pic13 and once the GOT size exceed 8,192 bytes, use -xcode=pic32.

• If you are building an archive library for linking into shared libraries you should just use -xcode=pic32.

Compiling with the -xcode=pic13 or pic32 (or -pic or -PIC) options is recommended when building dynamic libraries. See the Solaris Linker and Libraries Guide.

3.4.118 –xcommonchk[={yes|no}]

Enable runtime checking of common block inconsistencies.

This option provides a debug check for common block inconsistencies in programs using TASK COMMON and parallelization. (See the discussion of the TASK COMMON directive in the “Parallelization” chapter in the Fortran Programming Guide.)

The default is -xcommonchk=no; runtime checking for common block inconsistencies is disabled because it will degrade performance. Use -xcommonchk=yes only during program development and debugging, and not for production-quality programs.

Compiling with -xcommonchk=yes enables runtime checking. If a common block declared in one source program unit as a regular common block appears somewhere else on a TASK COMMON directive, the program will stop with an error message indicating the first such inconsistency. -xcommonchk without a value is equivalent to -xcommonchk=yes.

3.4.119 –xcrossfile[={1|0}]

Enable optimization and inlining across source files.

Normally, the scope of the compiler’s analysis is limited to each separate file on the command line. For example, -O4’s automatic inlining is limited to subprograms defined and referenced within the same source file.

With -xcrossfile, the compiler analyzes all the files named on the command line as if they had been concatenated into a single source file.

–xcrossfile is only effective when used with -O4 or -O5.

Cross–file inlining creates a possible source file interdependence that would not normally be there. If any file in a set of files compiled together with -xcrossfile is changed, then all files must be recompiled to insure that the new code is properly inlined. See 3.4.45 –inline=[%auto][[,][no%]f1,…[no%]fn].

The default, without -xcrossfile on the command line, is -xcrossfile=0, and no cross-file optimizations are performed. To enable cross-file optimizations, specify -xcrossfile (equivalent to -xcrossfile=1).

Any .s assmbler source files in the compilation do not participate in the crossfile analysis. Also, the -xcrossfile flag is ignored if compiling with -S.

3.4.120 –xdebugformat={dwarf|stabs}

Sun Studio compilers are migrating the format of debugger information from the "stabs" format to the "dwarf" format. The default setting for this release is -xdebugformat=dwarf.

If you maintain software which reads debugging information, you now have the option to transition your tools from the stabs format to the dwarf format.

Use this option as a way of accessing the new format for the purpose of porting tools. There is no need to use this option unless you maintain software which reads debugger information, or unless a specific tool tells you that it requires debugger information in one of these formats.

-xdebugformat=stabs generates debugging information using the stabs standard format.

-xdebugformat=dwarf generates debugging information using the dwarf standard format.

If you do not specify -xdebugformat, the compiler assumes -xdebugformat=dwarf. It is an error to specify the option without an argument.

This option affects the format of the data that is recorded with the -g option. Some the format of that information is also controlled with this option. So -xdebugformat has a an effect even when -g is not used.

The dbx and Performance Analyzer software understand both stabs and dwarf format so using this option does not have any effect on the functionality of either tool.

This is a transitional interface so expect it to change in incompatible ways from release to release, even in a minor release. The details of any specific fields or values in either stabs or dwarf are also evolving.

Use the dwarfdump(1) command to determine the format of the debugging information in a compiled object or executable file.

3.4.121 –xdepend

Synonym for -depend.

3.4.122 –xF

Allow function–level reordering by the Performance Analyzer.

Allow the reordering of functions (subprograms) in the core image using the compiler, the performance analyzer and the linker. If you compile with the -xF option, then run the analyzer, you can generate a map file that optimizes the ordering of the functions in memory depending on how they are used together. A subsequent link to build the executable file can be directed to use that map by using the linker -Mmapfile option. It places each function from the executable file into a separate section. (The f95 —Mpath option also passes a regular file to the linker; see the description of the f95 —Mpath option.)

Reordering the subprograms in memory is useful only when the application text page fault time is consuming a large percentage of the application time. Otherwise, reordering may not improve the overall performance of the application. See the Program Performance Analysis Tools manual for further information on the analyzer.

3.4.123 –xfilebyteorder=options

Support file sharing between little-endian and big-endian platforms.

The flag identifies the byte-order and byte-alignment of data on unformatted I/O files. options must specify any combination of the following, but at least one specification must be present:

littlemax_align:spec

bigmax_align:spec

native:spec

max_align declares the maximum byte alignment for the target platform. Permitted values are 1, 2, 4, 8, and 16. The alignment applies to Fortran VAX structures and Fortran derived types that use platform-dependent alignments for compatibility with C language structures.

little specifies a "little-endian" file on platforms where the maximum byte alignment is max_align. For example, little4 specifies a 32-bit x86 file, while little16 describes a 64-bit x86 file.

big specifies a "big-endian" file with a maximum alignment of max_align. For example, big8 describes a 32-bit SPARC file, while big16 describes a 64-bit SPARC file.

native specifies a "native" file with the same byte order and alignment used by the compiling processor platform. The following are assumed to be "native":

spec must be a comma-separated list of the following:

%all

unit

filename

%all refers to all files and logical units except those opened as "SCRATCH", or named explicitly elsewhere in the -xfilebyteorder flag. %all can only appear once.

unit refers to a specific Fortran unit number opened by the program.

filename refers to a specific Fortran file name opened by the program.

3.4.123.1 Examples:

-xfilebyteorder=little4:1,2,afile.in,big8:9,bfile.out,12
-xfilebyteorder=little8:%all,big16:20

3.4.123.2 Notes:

This option does not apply to files opened with STATUS="SCRATCH". I/O operations done on these files are always with the byte-order and byte-alignment of the native processor.

The first default, when -xfilebyteorder does not appear on the command line, is -xfilebyteorder=native:%all.

A file name or unit number can be declared only once in this option.

When -xfilebyteorder does appear on the command line, it must appear with at least one of the little, big, or native specifications.

Files not explicitly declared by this flag are assumed to be native files. For example, compiling with -xfilebyteorder=little4:zork.out declares zork.out to be a little-endian 32-bit x86 file with a 4-byte maximum data alignment. All other files in the program are native files.

When the byte-order specified for a file is the same as the native processor but a different alignment is specified, the appropriate padding will be used even though no byte swapping is done. For example, this would be the case when compiling with -m64 for 64-bit x86 platforms and -xfilebyteorder=little4:filename is specified.

The declared types in data records shared between big-endian and little-endian platforms must have the same sizes. For example, a file produced by a SPARC executable compiled with -xtypemap=integer:64,real:64,double:128 cannot be read by an x86 executable compiled with -xtypemap=integer:64,real:64,double:64 since the default double precision data types will have different sizes. (However, note that starting with the release of Sun Studio 12 Update 1, double:128 is accepted on x64 processors.)

If an option that changes the alignment of the components within a VAX structure (such as —vax=struct_align) or a derived type (such as —aligncommon or —dalign) is used on one platform, the same alignment option has to be used on other platforms sharing the same unformatted data file whose content is affected by the alignment option.

An I/O operation with an entire UNION/MAP data object on a file specified as non-native will result in a runtime I/O error. You can only execute I/O operations using the individual members of the MAP (and not an entire VAX record containing the UNION/MAP) on non-native files.

3.4.124 –xhasc[={yes|no}]

Treat Hollerith constant as a character string in an actual argument list.

With -xhasc=yes, the compiler treats Hollerith constants as character strings when they appear as an actual argument on a subroutine or function call. This is the default, and complies with the Fortran standard. (The actual call list generated by the compiler contains hidden string lengths for each character string.)

With -xhasc=no, Hollerith constants are treated as typeless values in subprogram calls, and only their addresses are put on the actual argument list. (No string length is generated on the actual call list passed to the subprogram.)

Compile routines with -xhasc=no if they call a subprogram with a Hollerith constant and the called subprogram expects that argument as INTEGER (or anything other than CHARACTER).

Example:

demo% cat hasc.f
                call z(4habcd, ’abcdefg’)
                end
                subroutine z(i, s)
                integer i
                character *(*) s
                print *, "string length = ", len(s)
                return
                end
demo% f95 -o has0 hasc.f
demo% has0
 string length =   4    <-- should be 7
demo% f95 -o has1 -xhasc=no hasc.f
demo% has1
 string length =   7  <-- now correct length for s

Passing 4habcd to z is handled correctly by compiling with -xhasc=no.

This flag is provided to aid porting legacy Fortran 77 programs.

3.4.125 –xhelp={readme|flags}

Show summary help information.

-xhelp=readme

Show the online README file for this release of the compiler.

-xhelp=flags

List the compiler option flags. Equivalent to -help.

3.4.126 –xhwcprof[={enable | disable}]

(SPARC) Enable compiler support for dataspace profiling.

With -xhwcprof enabled, the compiler generates information that helps tools associate profiled load and store instructions with the data-types and structure members (in conjunction with symbolic information produced with -g) to which they refer. It associates profile data with the data space of the target, rather than the instruction space, and provides insight into behavior that is not easily obtained from only instruction profiling.

While you can compile a specified set of object files with -xhwcprof, this option is most useful when applied to all object files in the application. This will provide coverage to identify and correlate all memory references distributed in the application's object files.

If you are compiling and linking in separate steps, use -xhwcprof at link time as well.

An instance of -xhwcprof=enable or -xhwcprof=disable overrides all previous instances of -xhwcprof in the same command line.

-xhwcprof is disabled by default. Specifying -xhwcprof without any arguments is the equivalent to -xhwcprof=enable.

-xhwcprof requires that optimization be turned on and that the debug data format be set to dwarf (-xdebugformat=dwarf), which is the default with this release of Sun Studio..

The combination of -xhwcprof and -g increases compiler temporary file storage requirements by more than the sum of the increases due to -xhwcprof and -g specified alone.

The following command compiles example.f and specifies support for hardware counter profiling and symbolic analysis of data types and structure members using DWARF symbols:

f95 -c -O -xhwcprof -g  example.f            

For more information on hardware counter-based profiling, see the Sun Studio Performance Analyzer manual.

3.4.127 –xia[={widestneed|strict}]

(Solaris) Enable interval arithmetic extensions and set a suitable floating-point environment.

The default if not specified is -xia=widestneed.

Fortran extensions for interval arithmetic calculations are detailed in the Interval Arithmetic Programming Reference. See also 3.4.130 –xinterval[={widestneed|strict|no}].

The -xia flag is a macro that expands as follows:

3.4.128 –xinline=list

Synonym for -inline.

3.4.129 -xinstrument=[%no]datarace

Specify this option to compile and instrument your program for analysis by the Thread Analyzer.

(For information on the Thread Analyzer, see tha(1) for details.)

By compiling with this option you can then use the Performance Analyzer to run the instrumented program with collect -r races to create a data-race-detection experiment. You can run the instrumented code standalone but it runs more slowly.

Specify -xinstrument=no%datarace to turn off this feature. This is the default.

-xinstrument must be specified with an argument.

If you compile and link in seperate steps, you must specify -xinstrument=datarace in both the compilation and linking steps.

This option defines the preprocessor token __THA_NOTIFY. You can specify #ifdef __THA_NOTIFY to guard calls to libtha(3) routines.

This option also sets -g.

3.4.130 –xinterval[={widestneed|strict|no}]

(Solaris) Enable interval arithmetic extensions.

The optional value can be one of either no, widestneed or strict. The default if not specified is widestneed.

Fortran extensions for interval arithmetic calculations are detailed in the Fortran 95 Interval Arithmetic Programming Reference. See also 3.4.127 –xia[={widestneed|strict}].

3.4.131 –xipo[={0|1|2}]

Perform interprocedural optimizations.

Performs whole-program optimizations by invoking an interprocedural analysis pass. Unlike -xcrossfile, -xipo will perform optimizations across all object files in the link step, and is not limited to just the source files on the compile command.

-xipo is particularly useful when compiling and linking large multi-file applications. Object files compiled with this flag have analysis information compiled within them that enables interprocedural analysis across source and pre-compiled program files. However, analysis and optimization is limited to the object files compiled with -xipo, and does not extend to object files on libraries.

-xipo=0 disables, and -xipo=1 enables, interprocedural analysis. -xipo=2 adds interprocedural aliasing analysis and memory allocation and layout optimizations to improve cache performance. The default is -xipo=0, and if -xipo is specified without a value, -xipo=1 is used.

When compiling with -xipo=2, there should be no calls from functions or subroutines compiled without -xipo=2 (for example, from libraries) to functions or subroutines compiled with -xipo=2.

As an example, if you interpose on the function malloc() and compile your own version of malloc() with -xipo=2, all the functions that reference malloc() in any library linked with your code would also have to be compiled with -xipo=2. Since this might not be possible for system libraries, your version of malloc should not be compiled with -xipo=2.

When compiling and linking are performed in separate steps, -xipo must be specified in both steps to be effective.

Example using -xipo in a single compile/link step:

demo% f95 -xipo -xO4 -o prog  part1.f part2.f part3.f

The optimizer performs crossfile inlining across all three source files. This is done in the final link step, so the compilation of the source files need not all take place in a single compilation and could be over a number of separate compilations, each specifying -xipo.

Example using -xipo in separate compile/link steps:

demo% f95 -xipo -xO4 -c part1.f part2.f
demo% f95 -xipo -xO4 -c part3.f
demo% f95 -xipo -xO4 -o prog  part1.o part2.o part3.o

The object files created in the compile steps have additional analysis information compiled within them to permit crossfile optimizations to take place at the link step.

A restriction is that libraries, even if compiled with -xipo do not participate in crossfile interprocedural analysis, as shown in this example: