Why is assert a macro and not a function?

Question

My lecturer has asked me that in class, and I was wondering why is it a macro instead of a function?

Answer 1

This macro is disabled if, at the moment of including , a macro with the name NDEBUG has already been defined. This allows for a coder to include as many assert calls as needed in a source code while debugging the program and then disable all of them for the production version by simply including a line like:

#define NDEBUG 

at the beginning of its code, before the inclusion of .

Therefore, this macro is designed to capture programming errors, not user or run-time errors, since it is generally disabled after a program exits its debugging phase.

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Making it as function will increase some function calls and you can not control all such asserts in release mode.

If you use function then _FILE__, __LINE__ and __func__ will give the value of that assert function's code. Not that calling line or calling function's line.