1.49 -U

Removes any initial definition of the specified macro.

Syntax

-Uname
Where:
name
is the name of the macro to be undefined.
The macro name can be either:
  • A predefined macro.
  • A macro specified using the -D option.

Note

Not all compiler predefined macros can be undefined.

Usage

Specifying -Uname has the same effect as placing the text #undef name at the head of each source file.

Restrictions

The compiler defines and undefines macros in the following order:
  1. Compiler predefined macros.
  2. Macros defined explicitly, using -Dname.
  3. Macros explicitly undefined, using -Uname.
Related reference
1.3 -D
5.1 Predefined macros
1.24 -include
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