# multiple-processes, MP

Creates multiple processes that can be used to compile large numbers of source files at the same time.

## Syntax

Linux: | -multiple-processes[=n]

macOS: | -multiple-processes[=n]

Windows: | /MP[:n]

## Arguments

n | Is the maximum number of processes that the compiler should create.

## Default

OFF | A single process is used to compile source files.

## Description

This option creates multiple processes that can be used to compile large numbers of source files at the same time. It can improve performance by reducing the time it takes to compile source files on the command line.

This option causes the compiler to create one or more copies of itself, each in a separate process. These copies simultaneously compile the source files.

If n is not specified for this option, the default value is as follows:

- On Windows* systems, the value is based on the setting of the NUMBER_OF_PROCESSORS environment variable.

- On Linux* and macOS systems, the value is 2.

This option applies to compilations, but not to linking or link-time code generation.

To override default heuristics, specify option /MP-force. It ensures that n will be the maximum number of processes created regardless of other heuristics that may limit the number of processes.

## IDE Equivalent

Visual Studio: General > Multi-processor Compilation

## Alternate Options

None

Parent topic: Miscellaneous Options