diff --git a/src/os/unix/ngx_posix_init.c b/src/os/unix/ngx_posix_init.c
index 78c5d4be9..b38a81009 100644
--- a/src/os/unix/ngx_posix_init.c
+++ b/src/os/unix/ngx_posix_init.c
@@ -22,7 +22,7 @@ ngx_os_io_t ngx_os_io = {
     ngx_unix_recv,
     ngx_readv_chain,
     ngx_udp_unix_recv,
-    NULL,
+    ngx_unix_send,
     ngx_writev_chain,
     0
 };