warn_undefmacro

Controls the detection of undefined macros in #if and #elif directives.

Syntax

#pragma warn_undefmacro on | off | reset

Remarks

The following listing provides an example.

Listing: Example of Undefined Macro

#if BADMACRO == 4 /* WARNING: undefined macro. */

Use this pragma to detect the use of undefined macros (especially expressions) where the default value 0 is used. To suppress this warning message, check if macro defined first.

Note: A warning message is only issued when a macro is evaluated. A short-circuited "&&" or "||" test or unevaluated "?:" will not produce a warning message.