Conditionally compiling your source code

Conditional compilation is a simple mechanism that enables developers to maintain a single code base, but only consider some parts of the code for compilation to produce different executables, usually in order to run on different platforms, hardware or depend on different libraries or library versions. Common examples include using or ignoring code based on the compiler, platform (x86, x64, ARM, and so on), configuration (debug or release), or any user-defined specific conditions. In this recipe, we take a look at how conditional compilation works.

Getting ready

Conditional compilation is a technique used extensively for many purposes. In this recipe, we will look at several examples and explain how they work. The technique is not in any way limited to these examples. For the scope of this recipe, we will only consider the three major compilers, GCC, Clang, and VC++.

How to do it...

To conditionally compile portions of code, use the #if, #ifdef, and ...