Re: GCC and OpenMP

[Theodore Papadopoulo <Theodore dot Papadopoulo at sophia dot inria dot fr>]

cybernike wrote:
> I am confused. I thought GCC didn't support OpenMP until 4.2, but why my
> 4.1.2 GCC compiler recognizes the following OpenMP code. Is it safe to use?
>
> #include <omp.h>
> #include <stdio.h>
> int main (int argc, char *argv[]) {
> int id, nthreads;
> #pragma omp parallel private (id)
> {
>     id = omp_get_thread_num ();
>     printf (âHello World from thread %d\nâ, id);
>     #pragma omp barrier
>     if (id == 0) {
>         nthreads = omp_get_num_threads ();
>         printf (âThere are %d threads\nâ, nthreads);
>     }
> }
> return 0;
> }
>   
Let me guess, you are using a redhat system, right ?
The gcc 4.1.2 shipped with fedora had OpenMP support in it (ie it's not 
the stock gcc 4.1.2).
For me, it worked for simple examples, but I soon hit some bugs which 
made me switch to
cvs versions... 4.3 support has corrected many problems with regard to 
OpenMP as far as I can tell
and should give you a better OpenMP experience. Well, I'm not sure it 
makes a difference, but I was
using OpenMP with C++, so with C things might be different.