OpenMP
OpenMP is a library (application program interface - API) that supports parallel programming on shared memory parallel computers.
OpenMP has been developed by a consortium of vendors of parallel computers (DEC, HP, SGI, Sun, Intel, …) with the aim to have a standard programming interface for parallel shared-memory machines.
The OpenMP functions can be used inside Fortran, C and C++ programs.
They allow the parallel execution of code (parallel DO loop), the definition of shared data (SHARED) and synchronization of processes.