OpenMPn

OpenMPn is not a recognized programming standard. There is no official specification or widely used implementation by that name. The term appears to be a misspelling or variation of OpenMP, an established API for shared-memory parallel programming. This article therefore provides an overview of OpenMP.

OpenMP is a portable API that enables multi-threaded parallelism in C, C++, and Fortran programs running on shared-memory architectures. It uses a fork-join model augmented by a rich set of compiler directives, library routines, and environment controls that allow developers to specify parallel work and synchronization.

Key features include work-sharing constructs (parallel, for, sections), synchronization primitives (barrier, critical, atomic), data scoping clauses (private, shared, firstprivate, reduction), and, since OpenMP 3.x, tasking for fine-grained concurrency. Programs are typically annotated with pragmas or directives such as #pragma omp parallel to create threads and distribute work.

OpenMP is implemented by many compilers on major platforms and can be enabled at compile time with flags such as -fopenmp. While it enables scalable performance on multi-core CPUs, it targets shared memory and is not a replacement for distributed-memory models. The OpenMP Architecture Review Board oversees the standard, which has evolved through multiple versions into the 5.x series.