What exactly does an #if 0 … #endif block do?

Question

In C/C++

What happens to code placed between an #if 0/#endif block?

#if 0

//Code goes here

#endif
         


        

Answer 1

Not only does it not get executed, it doesn't even get compiled.

#if is a preprocessor command, which gets evaluated before the actual compilation step. The code inside that block doesn't appear in the compiled binary.

It's often used for temporarily removing segments of code with the intention of turning them back on later.