Including same header file in different files - C++

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I am working in a MFC project and i have a header and cpp file of my library, i include header file in different files. i have a global initialization of a char array in the header file because all the files need it. But when i compile it, understandably, it tells me that i have initialized the char array twice.

What I have tried:

I Tried using pragma once and the defining trick used in header files

C++

#ifndef MY_HEADER_FILE
#define MY_HEADER_FILE
//Initialization here

#endif

But the linker still gives error, how do we solve this issue?

Posted 17-Jun-20 2:47am

Harasees_Singh

Updated 17-Jun-20 6:52am

v2

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Richard MacCutchan · Answer 1 · 2020-06-17T02:55:00

Don't put initialisation in the header, put it in the implementation (i.e. the .cpp file). And using the #ifndef or #pragma statements merely prevent the header file from being included more than once in each compilation unit (again the .cpp file). It does not make it unique in the entire project. The above is something of a guess since you have not shown any of the relevant code.

KarstenK · Answer 2 · 2020-06-17T06:53:00

Solution 3

My recommendation is the usage of the modern #pragma once compiler directive instead of macros which also are a common source of strange bugs.

The latest development are modules but I am not using the actual Visual Studio and its toolchain.

Posted 17-Jun-20 6:53am

KarstenK