Hi,
I am trying to call C code from Julia.It works for 'regular' C code but now
I have code that (potentially) uses OpenMP which causes trouble. I am
trying to interpolate a function using a spline approximation. In short, if
I type:
gcc -shared -O3 nspline_omp.c -o libcspline.dll -ffast-math
and then call one of the functions in the library from Julia using ccall,
it works. But judging from the speed and comparison with other languages,
only 1 thread is used. The code certainly supports multi-threading, for a
my friend of mine on his Mac, it worked. If I type:
gcc -shared -O3 nspline_omp.c -o libcspline2.dll -ffast-math -fopenmp
iand try to call it from Julia, it doesn't work anymore, in particular:
LoadError: error compiling spline: could not load library "libcspline2.dll"
The specified module could not be found.
Libdl.dlopen("libcspline2.dll")
gives the same error. As an example, consider:
#include<omp.h>
int banana(int hello) {
int nt;
#pragma omp parallel
{
nt = omp_get_num_threads();
}
return nt;
}
#include <stdio.h>
int main() { printf("%d\n", banana(12)); }
which perfectly works when compiled as .exe (gcc helloworld.c -fopenmp). When I
try to compile
#include <stdlib.h>
#include <omp.h>
int banana(int hello) {
int nt;
#pragma omp parallel
{
nt = omp_get_num_threads();
}
return nt;
}
as a shared library using
gcc -shared -O3 helloworld2.c -o libcpsline3.dll -ffast-math -fopenmp
and then in Julia:
Libdl.dlopen("libcspline3.dll")
LoadError: could not load library "libcspline3.dll"
The specified module could not be found.
Finally, I am new to Julia and C and basically I have not much of an idea what
I am doing, so it could be an obvious mistake. Thanks for your help.
