diff --git a/win32/select.c b/win32/select.c
index bdc53e8181b..33e5fb2aa29 100644
--- a/win32/select.c
+++ b/win32/select.c
@@ -66,7 +66,7 @@ PHPAPI int php_select(php_socket_t max_fd, fd_set *rfds, fd_set *wfds, fd_set *e
 	FD_ZERO(&sock_except);
 
 	/* build an array of handles for non-sockets */
-	for (i = 0; i < max_fd; i++) {
+	for (i = 0; (uint32_t)i < max_fd; i++) {
 		if (SAFE_FD_ISSET(i, rfds) || SAFE_FD_ISSET(i, wfds) || SAFE_FD_ISSET(i, efds)) {
 			handles[n_handles] = (HANDLE)(zend_uintptr_t)_get_osfhandle(i);
 			if (handles[n_handles] == INVALID_HANDLE_VALUE) {