diff --git a/app/xclock/configure.ac b/app/xclock/configure.ac
index 9dc15f628..384c9c4c7 100644
--- a/app/xclock/configure.ac
+++ b/app/xclock/configure.ac
@@ -39,7 +39,7 @@ AC_CONFIG_HEADERS([config.h])
 
 
 
-AC_CHECK_FUNCS([strlcpy getpid])
+AC_CHECK_FUNCS([strlcpy getpid pledge])
 
 AM_ICONV
 
diff --git a/app/xclock/xclock.c b/app/xclock/xclock.c
index 2533dede2..36daa16fd 100644
--- a/app/xclock/xclock.c
+++ b/app/xclock/xclock.c
@@ -37,6 +37,9 @@ in this Software without prior written authorization from The Open Group.
 # include "config.h"
 #endif
 
+#ifdef HAVE_PLEDGE
+# include <err.h>
+#endif
 #include <stdio.h>
 #include <stdlib.h>
 #include <X11/Xatom.h>
@@ -224,6 +227,11 @@ main(int argc, char *argv[])
     }
 #endif
 
+#ifdef HAVE_PLEDGE
+    if (pledge("stdio", NULL) == -1)
+	    err(1, "pledge");
+#endif
+
     XtAppMainLoop (app_con);
     exit(0);
 }