x in main: 999 x in foo: 10 x in foo: 20 x in bar: 20 x in bar: 40 x in main: 999
/* --- fileA.c --- */ int x = 8; /* external linkage, file scope */
/* --- fileB.c --- */ #include <stdio.h> static int x = 10 ; /* internal linkage, file scope */ void foo( ) { printf("x in foo: %d\n", x ); x = x+10 ; printf("x in foo: %d\n", x ); } void bar( ) { printf("x in bar: %d\n", x ); x = 2*x ; printf("x in bar: %d\n", x ); }
/* --- fileC.c --- */ #include <stdio.h> void foo(); void bar(); static int x = 999; /* internal linkage, file scope */ void main() { printf("x in main: %d\n", x ); foo(); bar(); printf("x in main: %d\n", x ); }
Comments:
main() sees the x in its file
that has internal linkage.
The two functions in fileB.c both see the x in that file
that has internal linkage (which is a different x from what main() sees.
There is an external object, also named x,
but no function uses it.