handle Winsock select() WSAEINVAL
diff --git a/src/event/modules/ngx_select_module.c b/src/event/modules/ngx_select_module.c
index a50088b..f702080 100644
--- a/src/event/modules/ngx_select_module.c
+++ b/src/event/modules/ngx_select_module.c
@@ -314,7 +314,21 @@
#if (NGX_WIN32)
- ready = select(0, &work_read_fd_set, &work_write_fd_set, NULL, tp);
+ if (max_read || max_write) {
+ ready = select(0, &work_read_fd_set, &work_write_fd_set, NULL, tp);
+
+ } else {
+
+ /*
+ * Winsock select() requires that at least one descriptor set must be
+ * be non-null, and any non-null descriptor set must contain at least
+ * one handle to a socket. Otherwise select() returns WSAEINVAL.
+ */
+
+ ngx_msleep(timer);
+
+ ready = 0;
+ }
#else
