explicitly link intel icpc openmp

Question

I have the intel compiler install at the following $HOME/tpl/intel. When I compile a simple hello_omp.cpp with openMP enabled

#include <omp.h>
#include <iostream>

int main ()
{
#pragma omp parallel

    {
        std::cout << "Hello World" << std::endl;
    }
    return 0;
}

I compile with ~/tpl/intel/bin/icpc -O3 -qopenmp hello_omp.cpp but when I run I get the following error: ./a.out: error while loading shared libraries: libiomp5.so: cannot open shared object file: No such file or directory.

I would like to explicitly link the intel compiler and the appropriate library during the make process without using the LD_LIBRARY_PATH?

Answer 1

You have 2 simple solutions for your problem:

1. Linking statically with the Intel run time libraries:
   ~/tpl/intel/bin/icpc -O3 -qopenmp -static_intel hello_omp.cpp
   
   • Pros: you don't have to care where the Intel run time environment is installed on the machine where you run the binary, or even having it installed altogether;
   • Cons: your binary becomes bigger and won't allow to select a different (more recent ideally) run time environment even when it is available.
2. Adding the search path for dynamic library into the binary using the linker option -rpath:
   ~/tpl/intel/bin/icpc -O3 -qopenmp -Wl,-rpath=$HOME/tpl/intel/lib/intel64 hello_omp.cpp
   Notice the use of -Wl, to transmit the option to the linker.
   I guess that is more like what you were after than the first solution I proposed so I let you devise what the pros and cons are for you in comparison.

Answer 2

Intel Compiler ships compilervars.sh script in the bin directory which when sourced will set the appropriate env variables like LD_LIBRARY_PATH, LIBRARY_PATH and PATH with the right directories which host OpenMP runtime library and other compiler specific libraries like libsvml (short vector math library) or libimf (more optimized version of libm).