OMP_LOCK(3) Last changed: 2-24-98
NAME
omp_init_lock, omp_destroy_lock, omp_set_lock, omp_unset_lock,
omp_test_lock, OMP_INIT_LOCK, OMP_DESTROY_LOCK, OMP_SET_LOCK,
OMP_UNSET_LOCK, OMP_TEST_LOCK, - Set of procedures to manipulate
locks
SYNOPSIS
C/C++: (Deferred implementation)
#integer <omp_init_lock>
void omp_init_lock(var)
#integer <omp_destroy_lock>
void omp_destory_lock(var)
#integer <omp_set_lock>
void omp_set_lock(var)
#integer <omp_unset_lock>
void omp_unset_lock(var)
#integer <omp_test_lock>
int omp_test_lock(var)
Fortran:
CALL OMP_INIT_LOCK(var)
CALL OMP_DESTROY_LOCK(var)
CALL OMP_SET_LOCK(var)
CALL OMP_UNSET_LOCK(var)
LOGICAL OMP_TEST_LOCK(var)IMPLEMENTATION
IRIX systems
STANDARDS
OpenMP Fortran API
DESCRIPTION
The following descriptions contain information for Fortran and C/C++.
omp_init_lock, OMP_INIT_LOCK
This subroutine initializes a lock associated with the lock
variable var for use in subsequent calls.
The initial state is unlocked. The lock variable must only be
accessed through these routines. In this and the following lock
routines, var should be a scalar integer variable in C and of
type integer in Fortran and must have a size large enough to hold
an address. For example, for 64-bit addressable systems, the
variable must at least by declared as INTEGER*8.
omp_destory_lock, OMP_DESTROY_LOCK
This procedure disassociates the given lock variable var from any
locks.
omp_set_lock, OMP_SET_LOCK
This procedure constrins the executing thread to wait until the
specified lock is available. The thread is granted ownership of
the lock when it is available.
omp_unset_lock, OMP_UNSET_LOCK
This procedure releases the executing thread from ownership of
the lock. The behavior is undefined if the thread does not own
that lock.
omp_test_lock, OMP_TEST_LOCK
This function tries to set the lock associated with the lock
variable var. It returns non-zero (TRUE) if the lock is
successfully set; otherwise, it returns zero (FALSE).
EXAMPLES
In the following Fortran 90 example, the argument to the lock routines
should be of size POINTER:
PROGRAM LOCK_USAGE
EXTERNAL OMP_TEST_LOCK
LOGICAL OMP_TEST_LOCK
INTEGER LCK ! THIS VARIABLE SHOULD BE POINTER SIZED
CALL OMP_INIT_LOCK(LCK)
!$OMP PARALLEL SHARED(LCK)PRIVATE(ID)
ID = OMP_GET_THREAD_NUM()
CALL OMP_SET_LOCK(LCK)
PRINT *, 'MY THREAD ID IS ', ID
CALL OMP_UNSET_LOCK(LCK)
DO WHILE (.NOT. OMP_TEST_LOCK(LCK))
CALL SKIP(ID) ! WE DO NOT YET HAVE THE LOCK
! SO WE MUST DO SOMETHING ELSE
END DO
CALL WORK(ID) ! WE NOW HAVE THE LOCK
! AND CAN DO THE WORK
CALL OMP_UNSET_LOCK( LCK )
!$OMP END PARALLEL
CALL OMP_DESTROY_LOCK( LCK )
END
SEE ALSOomp_nested(3) to manipulate or report status of nested parallelism,
omp_threads(3) for runtime library procedures used to set, call or
return numbers of threads
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