From: Christoph Bartoschek <bartoschek@gmx.de>
To: gcc-help@gcc.gnu.org
Subject: Openmp sections
Date: Sat, 29 Mar 2008 17:27:00 -0000 [thread overview]
Message-ID: <200803291829.20534.bartoschek@gmx.de> (raw)
Hi,
why is the following code not executed in parallel:
#include <iostream>
#include <omp.h>
int main()
{
#pragma omp sections nowait
{
#pragma omp section
{
int i = 0;
while (true) {
++i;
if (i % 1000000 == 0) {
std::cerr << "1. Thread: " << omp_get_thread_num()
<< " i = " << i << std::endl;
}
}
}
#pragma omp section
{
int i;
while (true) {
++i;
if (i % 1000000 == 0) {
std::cerr << "2. Thread: " << omp_get_thread_num()
<< " i = " << i << std::endl;
}
}
}
}
}
I know that the usage of std::cerr is not threadsafe. But this is only to see
that only one thread is running. If I remove it, there still only one thread
running.
I use g++ 4.3.0 and compile with:
g++ -fopenmp test.C -lgomp
./a.out prints only messages from 1. Thread.
Greetings
Christoph
next reply other threads:[~2008-03-29 17:27 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-29 17:27 Christoph Bartoschek [this message]
2008-03-29 17:42 ` Christoph Bartoschek
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