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Title: Compile OpenMp File
Post by: dm83 on December 03, 2010, 11:30:37 AM

Hi everybody,

I'm a new user on this forum so i excuse with you for all my mistakes.

i have to compile a c source file in OpenMp ambient. when i compile the file, the code blocks' compiler don't recognize the parallel regions. In

fact i should add the -fopenmp option to compiler.

How can i do this?

Thank you very very much.

Bye bye all!!!

Title: Re: Compile OpenMp File
Post by: killerbot on December 03, 2010, 12:41:12 PM

build options of your project -> Compiler settings -> Other options :
put there the -fopenmp

Maybe you also need to link with an openmp library, it has been some time since I used OpenMP, but I had it working with CB ;-)

Title: Re: Compile OpenMp File
Post by: dm83 on December 03, 2010, 01:45:04 PM

Thank you but I have already do this but it didn't work.

I have also imported the omp.h library.

What can i do?

Title: Re: Compile OpenMp File
Post by: dm83 on December 03, 2010, 02:10:55 PM

This is my code:

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

void main()
{
int x,nt,tid;

int ris;

omp_set_nested(1);

ris=omp_get_nested();

if (ris)

printf("Nested parallelism enabled\n");

omp_set_num_threads(5);

#pragma omp parallel private (nt,tid)
{
tid = omp_get_thread_num();

printf("Ciao sono il thread %d\n",tid);

nt = omp_get_num_threads();

if (omp_get_thread_num()==1)

printf("Il numero di threads e': %d\n",nt);
}

omp_set_num_threads(3);

#pragma omp parallel private (x)
{
x=x+1;

printf("Valore = %d\n",x);

}
}

and this is the response of the compiler:

Prova.c undefined reference to 'omp_set_nested'
Prova.c undefined reference to 'omp_get_nested'
Prova.c undefined reference to 'omp_set_num_threads'
Prova.c undefined reference to 'GOMP_parallel_start'
Prova.c undefined reference to 'GOMP_parallel_end'
Prova.c undefined reference to 'omp_set_num_threads'
Prova.c undefined reference to 'GOMP_parallel_start'
Prova.c undefined reference to 'GOMP_parallel_end'

build finished: 8 errors, 0 warnings

Title: Re: Compile OpenMp File
Post by: oBFusCATed on December 03, 2010, 02:16:51 PM

Read this please: http://wiki.codeblocks.org/index.php?title=FAQ#Q:_How_do_I_troubleshoot_an_compiler_problem.3F
Also please use code tags for such long pastes

Title: Re: Compile OpenMp File
Post by: killerbot on December 03, 2010, 02:35:56 PM

as said link with the omp library

Title: Re: Compile OpenMp File
Post by: killerbot on December 05, 2010, 09:41:37 AM

looked up my CB-OMP projects.

This is what you need to do :

compiler options : -fopenmp
linker options : add the library : libgomp

Snipper from the cbp file :

Code Select


		<Compiler>
			<Add option="-Wall" />
			<Add option="-fexceptions" />
			<Add option="-fopenmp" />
		</Compiler>
		<Linker>
			<Add library="libgomp" />
		</Linker>

Title: Re: Compile OpenMp File
Post by: Jenna on December 05, 2010, 10:25:03 AM

In the Projects "Build options -> Linker settings -> Link libraries" itshould be enough to add "gomp" (the lib prefix will not be used on commandline, just "-lgomp").

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User forums => Help => Topic started by: dm83 on December 03, 2010, 11:30:37 AM