NAG FL Interface
x06aff (in_​parallel)

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1 Purpose

x06aff returns 1 if called from within an active OpenMP parallel region, and 0 otherwise.

2 Specification

Fortran Interface
Function x06aff ( )
Integer :: x06aff
C Header Interface
#include <nag.h>
Integer  x06aff_ ()
The routine may be called by the names x06aff or nagf_omp_in_parallel.

3 Description

x06aff, for multithreaded implementations, returns 1 if called from within an active OpenMP parallel region, and 0 otherwise.
Note that the equivalent OpenMP routine omp_in_parallel() returns a logical value.
In serial implementations of the NAG Library this routine will always return 0. See the X06 Chapter Introduction for a discussion of the behaviour of these routines when called in serial.

4 References

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

5 Arguments

None.

6 Error Indicators and Warnings

None.

7 Accuracy

Not applicable.

8 Parallelism and Performance

Background information to multithreading can be found in the Multithreading documentation.
x06aff is not threaded in any implementation.

9 Further Comments

None.

10 Example

See x06adf for a demonstration of how to use x06aff.