# u (Windows*)

Undefines all previously defined preprocessor values.

## Syntax

Linux: | None

macOS: | None

Windows: | /u

## Arguments

None

## Default

OFF | Defined preprocessor values are in effect until they are undefined.

## Description

This option undefines all previously defined preprocessor values.

To undefine specific preprocessor values, use the /U option.

## IDE Equivalent

Visual Studio: Preprocessor > Undefine All Preprocessor Definitions

## Alternate Options

None

Parent topic: Preprocessor Options

## See Also

U compiler option