C Directive

!$PRAGMA C(list)

Declares a list of names of external functions as C language routines.

IGNORE_TKR Directive

!$PRAGMA IGNORE_TKR {name {, name} ...}

The compiler ignores the type, kind, and rank of the specified dummy argument

names appearing in a generic procedure interface when resolving a specific call.

UNROLL Directive

!$PRAGMA SUN UNROLL=n

Advises the compiler that the following loop can be unrolled to a length n.

WEAK Directive

!$PRAGMA WEAK(name[=name2])

Declares name to be a weak symbol, or an alias for name2.

Appendix C • Fortran Directives Summary

223

OPT Directive

!$PRAGMA SUN OPT=n

Set optimization level for a subprogram to n.

PIPELOOP Directive

!$PRAGMA SUN PIPELOOP[=n]

Assert dependency in loop between iterations n apart.

PREFETCH Directives

!$PRAGMA SUN_PREFETCH_READ_ONCE (name)

!$PRAGMA SUN_PREFETCH_READ_MANY (name)

!$PRAGMA SUN_PREFETCH_WRITE_ONCE (name)

!$PRAGMA SUN_PREFETCH_WRITE_MANY (name)

Request compiler generate prefetch instructions for references to name. (Requires -

xprefetch option, which is enabled by default. Prefetch directives can be disabled

by compiling with —xprefetch=no. Target architecture must also support prefetch

instructions, and the compiler optimization level must be set greater than —xO2.)

ASSUME Directives

!$PRAGMA [BEGIN} ASSUME (expression [,probability])

!$PRAGMA END ASSUME

Make assertions about conditions at certain points in the program that the compiler

can assume are true.

Format

!DIR$ directive : initial line

!DIR$& ... : continuation line

With fixed-format source, C is also accepted as a directive-indicator:

CDIR$ directive...

The line must start in column 1. With free-format source, the line may be preceded by

blanks.

FIXED/FREE Directives

!DIR$ FREE!DIR$ FIXED

These directives specify the source format of the lines following the directive. They

apply to the rest of the source file in which they appear, up to the next FREE or FIXED

directive.

IVDEP

!DIR$ IVDEP

Appendix C • Fortran Directives Summary

225