Internal linkage

 

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Within one translation unit, each declaration of an identifier with internal linkage denotes the same object or function.

If the declaration of a file scope identifier for an object or a function contains the storage-class specifier static, the identifier has internal linkage.

Notes

Code in other translation units cannot access objects and functions with internal linkage.

The other use of the keyword static is static storage duration.

Example

Identifiers a and f have internal linkage.

Run this code

#include <stdio.h>
 
static int a = 1;
 
static void f (void) {printf("from function f()\n");}
 
int main(void)
{
    f();
 
    return 0;
}
/* end of this translation unit */

Possible output:

from function f()