CODEWITHSUNDEEP
c++dlldllimportdllexportdata-sharing
user1414260
user1414260

Reputation: 11

Sharing variables between multiple Dlls in C++

I need to share a variables (1000s) between 2 C++ Dlls. How should I do that?

MyVariables.Dll contains:

int a = 0;

ModifyMyVariables.Dll contains:

extern int a;    
a++; 
// do more stuff with a;

What am i supposed to write in the following files?

myvariables.h
myvariables.cpp
ModifyMyVariables.h
ModifyMyVariables.cpp

Upvotes: 0

Views: 4046

Answers (1)

mox
mox

Reputation: 6314

You can share data between images (EXE, DLL...) using several fundamental mechanisms (using extern does not work to share data - it only instructs the linker and not the loader!)

  1. using import/export symbols (using the standard Import Address Table/Export Table)
  2. using static sections containing your data
  3. using dynamic sections containing your data

In your case, I would use the sections. This works pretty good. You must, of course, take care of the synchronisation when accessing (writing) these data from both sides.

Upvotes: 1

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