Compiler Directives

The following table lists available compiler directives.

Each general directive name is preceded by the prefix cDEC$; for example, cDEC$ ALIAS. Each OpenMP* Fortran directive name is preceded by the prefix c$OMP; for example, c$OMP ATOMIC. The c in either can be a c, C, *, or ! in fixed-form source code; only ! in free-form source code.

General Directives
Name	Description
ALIAS	Specifies an alternate external name to be used when referring to external subprograms.
ASSUME_ALIGNED	Specifies that an entity in memory is aligned.
ATTRIBUTES	Applies attributes to variables and procedures.
DECLARE	Generates warning messages for undeclared variables.
DEFINE	Creates a variable whose existence can be tested during conditional compilation.
DISTRIBUTE POINT	Specifies distribution for a DO loop.
ELSE	Marks the beginning of an alternative conditional-compilation block to an IF directive construct.
ELSEIF	Marks the beginning of an alternative conditional-compilation block to an IF directive construct.
ENDIF	Marks the end of a conditional-compilation block.
FIXEDFORMLINESIZE	Sets fixed-form line length. This directive has no effect on freeform code.
FREEFORM	Uses freeform format for source code.
IDENT	Specifies an identifier for an object module.
IF	Marks the beginning of a conditional-compilation block.
IF DEFINED	Marks the beginning of a conditional-compilation block.
INTEGER	Selects default integer size.
IVDEP	Assists the compiler's dependence analysis of iterative DO loops.
LOOP COUNT	Specifies the loop count for a DO loop; this assists the optimizer.
MEMORYTOUCH¹	Ensures that a specific memory location is updated dynamically.
MEMREF_CONTROL¹	Lets you provide cache hints on prefetches, loads, and stores.
MESSAGE	Sends a character string to the standard output device.
NODECLARE	(Default) Turns off warning messages for undeclared variables.
NOFREEFORM	(Default) Uses standard FORTRAN 77 code formatting column rules.
NOPARALLEL	Disables auto-parallelization for an immediately following DO loop.
NOOPTIMIZE	Disables optimizations.
NOPREFETCH	Disables a data prefetch from memory.
NOSTRICT	(Default) Disables a previous STRICT directive.
NOSWP¹	Disables software pipelining for a DO loop.
NOUNROLL	Disables the unrolling of a DO loop.
NOUNROLL_AND_JAM	Disables loop unrolling and jamming.
NOVECTOR²	Disables vectorization of a DO loop.
OBJCOMMENT	Specifies a library search path in an object file.
OPTIMIZE	Enables optimizations.
OPTIONS	Controls whether fields in records and data items in common blocks are naturally aligned or packed on arbitrary byte boundaries.
PACK	Specifies the memory starting addresses of derived-type items.
PARALLEL	Enables auto-parallelization for an immediately following DO loop.
PREFETCH	Enables a data prefetch from memory.
PSECT	Modifies certain characteristics of a common block.
REAL	Selects default real size.
STRICT	Disables Intel® Fortran features not in the language standard specified on the command line (Fortran 95 or Fortran 90).
SWP¹	Enables software pipelining for a DO loop.
UNDEFINE	Removes a symbolic variable name created with the DEFINE directive.
UNROLL	Tells the compiler's optimizer how many times to unroll a DO loop.
UNROLL_AND_JAM	Enables loop unrolling and jamming.
VECTOR ALIGNED	Specifies that all data is aligned in a DO loop.
VECTOR ALWAYS	Enables vectorization of a DO loop.
VECTOR NONTEMPORAL²	Directs the compiler to use non-temporal (that is, streaming) stores.
VECTOR NOVECTOR	Disables vectorization of a DO loop.
VECTOR TEMPORAL²	Directs the compiler to use temporal (that is, non-streaming) stores.
VECTOR UNALIGNED	Specifies that no data is aligned in a DO loop.

¹i64 only

²i32, i64em

To use the following directives, you must specify compiler option -openmp (Linux and Mac OS X) or /Qopenmp (Windows).

OpenMP Fortran Directives
Name	Description
ATOMIC	Specifies that a specific memory location is to be updated dynamically.
BARRIER	Synchronizes all the threads in a team.
CRITICAL	Restricts access for a block of code to only one thread at a time.
DO	Specifies that the iterations of the immediately following DO loop must be executed in parallel.
FLUSH	Specifies synchronization points where the implementation must have a consistent view of memory.
MASTER	Specifies a block of code to be executed by the master thread of the team.
ORDERED	Specifies a block of code to be executed sequentially.
PARALLEL	Defines a parallel region.
PARALLEL DO	Defines a parallel region that contains a single DO directive.
PARALLEL SECTIONS	Defines a parallel region that contains SECTIONS directives.
PARALLEL WORKSHARE	Defines a parallel region that contains a single WORKSHARE directive.
SECTIONS	Specifies a block of code to be divided among threads in a team (a worksharing area).
SINGLE	Specifies a block of code to be executed by only one thread in a team.
TASK	Defines a task region.
TASKWAIT	Specifies a wait on the completion of child tasks generated since the beginning of the current task.
THREADPRIVATE	Makes named common blocks private to a thread but global within the thread.
WORKSHARE	Divides the work of executing a block of statements or constructs into separate units.