diff --git a/vl.c b/vl.c
index 70950f8..3c1a476 100644
--- a/vl.c
+++ b/vl.c
@@ -4423,7 +4423,8 @@
 {
     int so_type=-1, optlen=sizeof(so_type);
 
-    if(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&so_type, &optlen)< 0) {
+    if(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&so_type,
+        (socklen_t *)&optlen)< 0) {
 	fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n", fd);
 	return NULL;
     }