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#include <stdio.h>
#include <stdlib.h>
#ifdef _OPENMP
#include <omp.h>
#endif
#include <pthread.h>
enum {
Size = 10000
};
const int ShouldSum = (Size-1)*Size/2;
short Verbose = 1;
short ThreadOK[3] = {0,0,0}; // Main, Thread1, Thread2
// Thread
void *_thread(void* Id) {
int i;
int x[Size];
#ifdef _OPENMP
#pragma omp parallel for
#endif
for ( i = 0; i < Size; i++ ) {
#ifdef _OPENMP
if (Verbose && i%1000==0) {
int tid = omp_get_thread_num();
#pragma omp critical
printf("thread %d : tid %d handles %d\n",(int)Id,tid,i);
}
#endif
x[i] = i;
}
int Sum=0;
for ( i = 0; i < Size; i++ ) {
Sum += x[i];
}
if (Verbose) {
#ifdef _OPENMP
#pragma omp critical
#endif
printf("Id %d : %s : %d(should be %d)\n",(int)Id, __FUNCTION__, Sum,ShouldSum);
}
if (Sum == ShouldSum) ThreadOK[(int)Id] = 1;
return NULL;
}
// MainThread
void MainThread() {
int i;
#ifdef _OPENMP
#pragma omp parallel for
#endif
for ( i = 0; i < 4; i++ ) {
#ifdef _OPENMP
int tid = omp_get_thread_num();
#pragma omp critical
printf("Main : tid %d\n",tid);
_thread((void *)tid);
#endif
}
return;
}
// Comment in/out for checking the effect of multiple threads.
#define SPAWN_THREADS
// main
int main(int argc, char *argv[]) {
if (argc>1) Verbose = 1;
#ifdef _OPENMP
omp_set_nested(-1);
printf("%s%s%s\n", "Nested parallel blocks are ", omp_get_nested()?" ":"NOT ", "supported.");
#endif
MainThread();
#ifdef SPAWN_THREADS
{
pthread_t a_thr;
pthread_t b_thr;
int status;
printf("%s:%d - %s - a_thr:%p - b_thr:%p\n",
__FILE__,__LINE__,__FUNCTION__,a_thr.p,b_thr.p);
status = pthread_create(&a_thr, NULL, _thread, (void*) 1 );
if ( status != 0 ) {
printf("Failed to create thread 1\n");
return (-1);
}
status = pthread_create(&b_thr, NULL, _thread, (void*) 2 );
if ( status != 0 ) {
printf("Failed to create thread 2\n");
return (-1);
}
status = pthread_join(a_thr, NULL);
if ( status != 0 ) {
printf("Failed to join thread 1\n");
return (-1);
}
printf("Joined thread1\n");
status = pthread_join(b_thr, NULL);
if ( status != 0 ) {
printf("Failed to join thread 2\n");
return (-1);
}
printf("Joined thread2\n");
}
#endif
short OK = 0;
// Check that we have OpenMP before declaring things OK formally.
#ifdef _OPENMP
OK = 1;
{
short i;
for (i=0;i<3;i++) OK &= ThreadOK[i];
}
if (OK) printf("OMP : All looks good\n");
else printf("OMP : Error\n");
#else
printf("OpenMP seems not enabled ...\n");
#endif
return OK?0:1;
}
//g++ -fopenmp omp_test.c -o omp_test -lpthread
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