Why use precompiled headers (C/C++)?

Question

Why use precompiled headers?

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Reading the responses, I suspect what I\'ve been doing with them is kind of stupid:

#pragma once

// Defines used         


        

Answer 1

It speeds up compilation.

When you're including headers from other projects, you don't expect to change them. If you put these into a precompiled header, then that code will not have to be recompiled when you make changes to your source code. This reduces repetitive compilation of unchanged code, speeding up compile time.