int i1 = 1;
static int i2 = 2;
extern int i3 = 3;
int i4;
static int i5;





// definition, external linkage
// definition, internal linkage
// definition, external linkage
// tentative definition, external linkage // tentative definition, internal linkage
// valid tentative definition, refers to previous // 6.2.2 renders undefined, linkage disagreement // valid tentative definition, refers to previous // valid tentative definition, refers to previous // 6.2.2 renders undefined, linkage disagreement
// refers to previous, whose linkage is external // refers to previous, whose linkage is internal // refers to previous, whose linkage is external // refers to previous, whose linkage is external // refers to previous, whose linkage is internal