Question

I’m using a custom library in a c++ project, witch includes several std headers, but when i include the corresponding header in the main file, it’s like i included all the headers in the custom one.
To be clear:
custom header file:

#ifndef CUSTOM_H
#define CUSTOM_H

#include <vector>

//stuff

#endif

Main.cpp:

#include <iostream>
#include "custom.h"

//here, let suppose that i do next:
vector<int> vec;

return 0;

there’s no compile error, like the vector header is included, i want to avoid that, any suggestion

Answer 1

If custom.h‘s use of std::vector is an implementation detail (and not exposed in the signatures of things you define in the header), consider moving the #include <vector> to the corresponding custom.cpp file instead.

If you can’t move the include out of custom.h because, say, you pass a vector in or out of a method, then it truly is part of your interface and clients of your header will need to know about it.