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Debugging macros can take a lot of time. We are much better off
avoiding them except in the very rare cases when neither constants,
functions nor templates can do what we want.
What are the rare cases?
If you want actual textual replacement, that’s where you use macros. Take a look at Boost.Preprocessor, it’s a great way to simulate variadic templates in C++03 without repeating yourself too much.
In other words, if you want to manipulate the program code itself, use macros.
Another useful application is
assert, which is defined to be a no-op whenNDEBUGis not defined (usually release mode compilation).That brings us to the next point, which is a specialization of the first one: Different code with different compilation modes, or between different compilers. If you want cross-compiler support, you can’t get away without macros. Take a look at Boost in general, it needs macros all the time because of various deficiencies in various compilers it has to support.
Another important point is when you need call-site information without wanting to bug the user of your code. You have no way to automatically get that with just a function.
With a suitable declaration of
has_info(and C++11/C99__func__or similar).