Is there any difference between global and extern variables in c?
global variables are those defined outside a function body
if declared static they are global to the file otherwise are global to the program, e.g.
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int x=10; // global to program
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static int y; // global to file from this point onwards
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int func()
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{
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int z; // local variable to function
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..
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}
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note global variables are initialised to 0 if not explicity initialised (as x was). Local variables are not initialised unless you explicity do so.
to access a global variable in another file you use the keyword extern, e.g.
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extern int x; // access x defined in another file
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