$ unset DISPLAY; xclip
Error: Can't open display: (null)
$ tail -1 /var/log/messages
Nov 18 11:53:55 mimine xclip: vfprintf %s NULL in "Error: Can't open display:
%s "
ok?
Index: Makefile
===================================================================
RCS file: /var/cvs/ports/x11/xclip/Makefile,v
retrieving revision 1.15
diff -u -p -r1.15 Makefile
--- Makefile 13 Sep 2016 20:13:38 -0000 1.15
+++ Makefile 18 Nov 2017 10:56:55 -0000
@@ -4,6 +4,7 @@ COMMENT= command line interface to X se
GH_ACCOUNT= astrand
GH_PROJECT= xclip
GH_TAGNAME= 0.13
+REVISION= 0
CATEGORIES= x11
MAINTAINER= Dmitrij D. Czarkoff <czark...@openbsd.org>
Index: patches/patch-xcprint_c
===================================================================
RCS file: patches/patch-xcprint_c
diff -N patches/patch-xcprint_c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ patches/patch-xcprint_c 18 Nov 2017 10:55:49 -0000
@@ -0,0 +1,19 @@
+$OpenBSD$
+
+Avoid printf "%s" NULL
+
+Index: xcprint.c
+--- xcprint.c.orig
++++ xcprint.c
+@@ -86,7 +86,10 @@ errxdisplay(char *display)
+ if (display == NULL)
+ display = getenv("DISPLAY");
+
+- fprintf(stderr, "Error: Can't open display: %s\n", display);
++ if (display == NULL || *display == '\0')
++ fprintf(stderr, "Error: Can't open display\n");
++ else
++ fprintf(stderr, "Error: Can't open display: %s\n", display);
+ exit(EXIT_FAILURE);
+ }
+
