CODEWITHSUNDEEP
c++windowsdll
Seb
Seb

Reputation: 3564

Using global variables in a C++ DLL

I have a C++ DLL with 3 classes in it. I added a static boolean variable to my "stdafx" header file (since all of my classes include it) and am trying to use it. While all of my classes see my variable, they each seem to have a different instance of it. If I set the variable to true in once class then I'll notice that it's false in another class. Is there any way that I can create a variable that can be used across all classes only within the DLL?

Upvotes: 0

Views: 3390

Answers (2)

Praetorian
Praetorian

Reputation: 109119

Your variable is static and you're declaring it in stdafx.h which is included by all source files in your project. This means each translation unit will contain its own copy of the variable, which is exactly the behavior you're seeing.

To solve this problem, declare the variable in stdafx.cpp 

bool MyBool = false;

Then extern it in stdafx.h

extern bool MyBool;

Upvotes: 2

Lightness Races in Orbit
Lightness Races in Orbit

Reputation: 385144

Well, you labelled it static, so that's what happens. Instead, label it extern in headers and define it in one TU.

And don't modify stdafx; it's not yours. Use your own shared headers.

Upvotes: 4

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