/in/foo.c: In function 'S':
/in/foo.c:14:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/in/foo.c: In function 'main':
/in/foo.c:46:2: warning: 'm' may be used uninitialized in this function [-Wmaybe-uninitialized]
  printf("%d %d",z,m);
  ^~~~~~~~~~~~~~~~~~~
/in/foo.c:46:2: warning: 'z' may be used uninitialized in this function [-Wmaybe-uninitialized]