diff --git a/c4.c b/c4.c
index 0340255..4351238 100644
--- a/c4.c
+++ b/c4.c
@@ -330,7 +330,7 @@ void stmt()
   }
 }
 
-int main(int argc, char **argv)
+signed main(signed argc, char **argv)
 {
   int fd, bt, ty, poolsz, *idmain;
   int *pc, *sp, *bp, a, cycle; // vm registers