CODEWITHSUNDEEP
cmacrosc-preprocessor
winuall
winuall

Reputation: 369

Usage of underscore as argument of a macro function

In C, what's the meaning of an underscore as a macro parameter?

#define FUNC(_) VALUE

Is it a dummy argument? any example for a use-case in which it'll fit?

Upvotes: 7

Views: 3371

Answers (2)

Iharob Al Asimi
Iharob Al Asimi

Reputation: 53006

The _ has no special meaning, I suppose they used it because it looks like if the argument is not there.

The _ is just a valid identifier, and hence it's taken so the macro requires one parameter, but it keeps the macro definition looking as if there was no parameter.

#define FUNC(ignoredParameter) VALUE

would be exaclty the same.

Upvotes: 7

jxh
jxh

Reputation: 70422

In this case, the code can be read as:

FUNC takes a single argument, but it doesn't care what it is. No matter what is passed in, VALUE is the result.

A single _ is a valid identifier in C, and is thus suitable for use as a macro argument name.

Upvotes: 6

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