get_num_threads returns the number of OpenMP threads in the current team.

For full information please refer to the NAG Library document for x06ab


The returned number of OpenMP threads in the current team.


get_num_threads, for multithreaded implementations, returns the number of OpenMP threads in the current team. If the number of threads is deemed critical then you are advised to use get_num_threads to retrieve this value as it may be less than that requested with either a call to set_num_threads(), your OMP_NUM_THREADS environment variable value or by using a num_threads clause on an OpenMP parallel directive.

The number of threads actually in use in a parallel region is dependent on several factors. Please refer to References for a full description of how the number of threads is chosen for a particular parallel region.

If this function is called from a sequential part of a multithreaded program then it will return the value .

In serial implementations of the NAG Library this function will always return . See the X06 Introduction for a discussion of the behaviour of these functions when called in serial.


The OpenMP API Specification for Parallel Programming

Chapman, B, Jost, G and van der Pas, R, 2008, Using OpenMP Portable Shared Memory Parallel Programming, The MIT Press