$ gcc foo.c
foo.c: In function ‘printm’:
foo.c:20:13: warning: ‘sizeof’ on array function parameter ‘target’ will return size of ‘int (*)[(sizetype)(c)]’ [-Wsizeof-array-argument]
  i = sizeof target / sizeof *target;
             ^
foo.c:17:25: note: declared here
 void printm (int c, int target[][c]){