More Exceptional C++

Chapter 34. Preprocessor Macros

Difficulty: 4

Preprocessor macros are part of C++'s heritage from C. This Item considers whether they are still relevant in the modern C++ scheme of things.

With flexible features such as overloading and type-safe templates available, why would a C++ programmer ever write a preprocessor directive like “#define”?

Solution

C++ features often, but not always, cancel out the need for using #define. For example, “const int c = 42;” is superior to “#define c 42” because it provides type safety, and avoids accidental preprocessor edits, among other reasons.

There are, however, still a few good reasons to write #define.

1. Header ...