# par-num-threads, Qpar-num-threads

Specifies the number of threads to use in a parallel region.

## Syntax

Linux: | -par-num-threads=n

macOS: | -par-num-threads=n

Windows: | /Qpar-num-threads:n

## Arguments

n | Is the number of threads to use. It must be a positive integer.

## Default

OFF | The number of threads to use is determined by the run-time environment.

## Description

This option specifies the number of threads to use in a parallel region. It has the same effect as environment variable OMP_NUM_THREADS.

This option overrides the environment variable when both are specified.

This option only has an effect if the following is true:

- You have specified option [Q]parallel or option [q or Q]openmp (or both).

- You are compiling the main program.

## IDE Equivalent

None

## Alternate Options

None

Parent topic: OpenMP* Options and Parallel Processing Options

## See Also

parallel, Qparallel compiler option
qopt-report, Qopt-report compiler option