diff --git a/lib/log.h b/lib/log.h
index 9f6ec3b..b5dbdfe 100644
--- a/lib/log.h
+++ b/lib/log.h
@@ -126,4 +126,7 @@
 
 extern const char *zlog_priority[];
 
+/* Safe version of strerror -- never returns NULL. */
+extern const char *safe_strerror(int errnum);
+
 #endif /* _ZEBRA_LOG_H */