diff --git a/os/connection.c b/os/connection.c
index 5294e5955..40d9ff39b 100644
--- a/os/connection.c
+++ b/os/connection.c
@@ -353,8 +353,10 @@ NotifyParentProcess(void)
 {
 #if !defined(WIN32)
     if (displayfd >= 0) {
-        write(displayfd, display, strlen(display));
-        write(displayfd, "\n", 1);
+        if (write(displayfd, display, strlen(display)) != strlen(display))
+            FatalError("Cannot write display number to fd %d\n", displayfd);
+        if (write(displayfd, "\n", 1) != 1)
+            FatalError("Cannot write display number to fd %d\n", displayfd);
         close(displayfd);
         displayfd = -1;
     }