#C++

Most C++ compilers support the use of OpenMP. Available compilers include g++ (version 4.2 or above), icpc and pgCC.

The first step is to create a simple OpenMP C++ program, which we will call hello_openmp. Open a text editor (e.g. nano), create a file called hello_openmp.cpp and copy in the following code;

#include <iostream>

int main(int argc, const char **argv)
{
    #pragma omp parallel
    {
        std::cout << "Hello OpenMP!\n";
    }

    return 0;
}

The only new line in this example is #pragma omp parallel, which is used to specify that all of the code between the curly brackets is part of an OpenMP parallel section.

You can compile this program using one of these commands (choose one for the compiler you wish to use);

• g++ : g++ -fopenmp hello_openmp.cpp -o hello_openmp
• icpc : icpc -openmp hello_openmp.cpp -o hello_openmp -cxxlib-icc
• pgCC : pgCC -mp hello_openmp.cpp -o hello_openmp

This will produce the executable, hello_openmp.

Now return to the previous page to see how to run hello_openmp in parallel.