# OpenMP* Support

The Intel® C++ Compiler Classic supports most of the OpenMP* Application Programming Interface versions 5.0 and 5.1. For the complete OpenMP specification, read the specifications available from the OpenMP web site (http://www.openmp.org; see OpenMP Specifications on that site). The descriptions of OpenMP language characteristics in this documentation often use terms defined in that specification.

The OpenMP API provides symmetric multiprocessing (SMP) with the following major features:

- Relieves you from implementing the low-level details of iteration space partitioning, data sharing, thread creation, scheduling, or synchronization.

- Provides the benefit of performance available from shared memory multiprocessor and multi-core processor systems on all supported Intel architectures, including those processors with Intel® Hyper-Threading Technology (Intel® HT Technology).

The compiler performs transformations to generate multithreaded code based on your placement of OpenMP pragmas in the source program, making it simple to add threading to existing software. The compiler compiles parallel programs and supports the industry-standard OpenMP pragmas.

The compiler provides Intel®-specific extensions to the OpenMP specification including run-time library routines and environment variables. A summary of the compiler options appear in the OpenMP Options Quick Reference.

## Parallel Processing with OpenMP

To compile with the OpenMP API, add the pragmas to your code. The compiler processes the code and internally produces a multithreaded version which is then compiled into an executable with the parallelism implemented by threads that execute parallel regions or constructs.

## Using Other Compilers

The OpenMP specification does not define interoperability of multiple implementations, so the OpenMP implementation supported by other compilers and OpenMP support in the Intel® C++ Compiler Classic might not be interoperable. Even if you compile and build the entire application with one compiler, be aware that different compilers might not provide OpenMP source compatibility that enable you to compile and link the same set of application sources with a different compiler and get the expected parallel execution results.

Parent topic: Optimization and Programming

- Add OpenMP* Support
- Parallel Processing Model
- Worksharing Using OpenMP*
- Control Thread Allocation
- OpenMP* Pragmas
- OpenMP* Library Support
- OpenMP* Advanced Issues
- OpenMP* Implementation-Defined Behaviors
- OpenMP* Examples