hello_w.c

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

int main(int argc, char* argv[])
{
	int thread_count = omp_get_max_threads();
	if ( argc >= 2 )
		thread_count = atoi( argv[1] );
	
	#pragma omp parallel num_threads(thread_count)
	{
		#pragma omp critical (print)
		printf("Hello from thread %d of %d\n"
			, omp_get_thread_num()
			, omp_get_num_threads() );
	}
	
	return 0;
}