omp_test_nest_lock
Attempts to set a nestable lock but does not block thread execution.
int omp_test_nest_lock(
omp_nest_lock_t *lock
);
Remarks
where,
- lock
A variable of type omp_nest_lock_t that was initialized with omp_init_nest_lock.
Remarks
For more information, see 3.2.5 omp_test_lock and omp_test_nest_lock Functions.
Example
// omp_test_nest_lock.cpp
// compile with: /openmp
#include <stdio.h>
#include <omp.h>
omp_nest_lock_t nestable_lock;
int main() {
omp_init_nest_lock(&nestable_lock);
#pragma omp parallel num_threads(4)
{
int tid = omp_get_thread_num();
while (!omp_test_nest_lock(&nestable_lock))
printf_s("Thread %d - failed to acquire nestable_lock\n",
tid);
printf_s("Thread %d - acquired nestable_lock\n", tid);
if (omp_test_nest_lock(&nestable_lock)) {
printf_s("Thread %d - acquired nestable_lock again\n",
tid);
printf_s("Thread %d - released nestable_lock\n",
tid);
omp_unset_nest_lock(&nestable_lock);
}
printf_s("Thread %d - released nestable_lock\n", tid);
omp_unset_nest_lock(&nestable_lock);
}
omp_destroy_nest_lock(&nestable_lock);
}
Thread 1 - acquired nestable_lock Thread 0 - failed to acquire nestable_lock Thread 1 - acquired nestable_lock again Thread 0 - failed to acquire nestable_lock Thread 1 - released nestable_lock Thread 0 - failed to acquire nestable_lock Thread 1 - released nestable_lock Thread 0 - failed to acquire nestable_lock Thread 3 - acquired nestable_lock Thread 0 - failed to acquire nestable_lock Thread 3 - acquired nestable_lock again Thread 0 - failed to acquire nestable_lock Thread 2 - failed to acquire nestable_lock Thread 3 - released nestable_lock Thread 2 - failed to acquire nestable_lock Thread 3 - released nestable_lock Thread 2 - failed to acquire nestable_lock Thread 0 - acquired nestable_lock Thread 2 - failed to acquire nestable_lock Thread 2 - failed to acquire nestable_lock Thread 2 - failed to acquire nestable_lock Thread 0 - acquired nestable_lock again Thread 2 - failed to acquire nestable_lock Thread 0 - released nestable_lock Thread 2 - failed to acquire nestable_lock Thread 0 - released nestable_lock Thread 2 - failed to acquire nestable_lock Thread 2 - acquired nestable_lock Thread 2 - acquired nestable_lock again Thread 2 - released nestable_lock Thread 2 - released nestable_lock