OpenMP: #pragma omp parallel

omp_parallel.txt

#include <stdio.h>
#include <stdlib.h>
#include <omp.h>

int main(int argc, char *argv[])
{
	if (argc != 2) exit(0);

#pragma omp parallel num_threads(4)
	printf("Thread %d says %s\n", omp_get_thread_num(), argv[1]);

	return 0;
}

==============================================================================
After OpenMP lowering and expansion:
==============================================================================

/* libgomp/parallel.c:
 * - GOMP_parallel_start
 * - GOMP_parallel_end
 */

struct omp_data {
	char **argv;
};

void main_omp_fn_0(struct omp_data *omp_data)
{
	char **argv;

	argv = omp_data->argv;

	printf("Thread %d says %s\n", omp_get_thread_num(), argv[1]);
}

int main(int argc, char *argv[])
{
	struct omp_data omp_data;
	
	if (argc != 2) exit(0);

	omp_data.argv = argv;

	// Spawns a team of threads
	__builtin_GOMP_parallel_start(main_omp_fn_0, &omp_data, 4);

	main_omp_fn_0(&omp_data);
	
	// Terminates current team of threads 
	__builtin_GOMP_parallel_end();

	return 0;
}