HP C/aC++ for PA-RISC Software manual OMP Master Pragma, OMP Ordered Pragma, OMP Parallel Pragma

•at exit from single

•at exit from for

•at exit from sections

NOTE: The directive is not implied if a nowait clause is present.

OMP MASTER Pragma

#pragma omp master structured-block

The master pragma directs that the structured-blockfollowing it should be executed by the master thread (thread 0) of the team. Other threads in the team do not execute the associated block.

OMP ORDERED Pragma

#pragma omp ordered structured-block

The ordered pragma indicates that the following structured block should be executed in the same order in which iterations will be executed in a sequential loop.

An ordered directive must be within the dynamic extent of a for or a parallel for construct that has an ordered clause. When the ordered clause is used with schedule which has a chunksize, then the chunksize is ignored by the compiler.

OMP PARALLEL Pragma

#pragma omp parallel [clause1, clause2,...] structured-block

where [clause1, clause2, ...] indicates that the clauses are optional. There can be zero or more clauses.

clause can be one or more of the following:

•private(list)

•firstprivate(list)

•default(sharednone)

•shared(list)

•reduction(op:list)

•if (scalar-expression)

•copyin (list)

•num_threads

The parallel pragma defines a parallel region, which is a region of the program that is executed by multiple threads in parallel. This is the fundamental construct that starts parallel execution.

OMP PARALLEL FOR Pragma

#pragma omp parallel for [clause1, clause2, ... ] for-loop

where [clause1, clause2, ...] indicates that the clauses are optional. There can be zero or more clauses.

The parallel for pragma is a shortcut for a parallel region that contains a single for pragma. parallel for admits all the allowable clauses of the parallel pragma and the for pragma except for the nowait caluse.

112 Pragma Directives and Attributes