Use XDisplayName() when reporting errors (bug 8079).
diff --git a/progs/xdemos/opencloseopen.c b/progs/xdemos/opencloseopen.c
index 2e4de24..0b8d061 100644
--- a/progs/xdemos/opencloseopen.c
+++ b/progs/xdemos/opencloseopen.c
@@ -91,7 +91,7 @@
 
    dpy = XOpenDisplay(dpyName);
    if (!dpy) {
-      printf("Error: couldn't open display %s\n", dpyName);
+      printf("Error: couldn't open display %s\n", XDisplayName(dpyName));
       exit(1);
    }