How do I share variables between different .c files? [duplicate]

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In fileA.c:

int myGlobal = 0;

In fileA.h

extern int myGlobal;

In fileB.c:

#include "fileA.h"
myGlobal = 1;

So this is how it works:

  • the variable lives in fileA.c
  • fileA.h tells the world that it exists, and what its type is (int)
  • fileB.c includes fileA.h so that the compiler knows about myGlobal before fileB.c tries to use it.

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