diff --git a/sc2/src/sc2code/libs/network/netmanager/ndindex.ci b/sc2/src/sc2code/libs/network/netmanager/ndindex.ci
index bee4ecd1a..f922d8b62 100644
--- a/sc2/src/sc2code/libs/network/netmanager/ndindex.ci
+++ b/sc2/src/sc2code/libs/network/netmanager/ndindex.ci
@@ -45,7 +45,7 @@ NDIndex_uninit(void) {
 
 static inline int
 NDIndex_registerNDWithSocket(Socket *sock, NetDescriptor *nd) {
-	if (sock->fd >= FD_SETSIZE) {
+	if ((unsigned int) sock->fd >= FD_SETSIZE) {
 		errno = EMFILE;
 		return -1;
 	}