From aacd1628371129839fba01722e14e6c7ce1bda2a Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Fri, 4 Nov 2016 09:59:51 -0700
Subject: [PROPOSED] Add zic.c comment

* zic.c (dolink): Say why EEXIST optimization is valid.
---
 zic.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/zic.c b/zic.c
index b8e8e03..47c68f9 100644
--- a/zic.c
+++ b/zic.c
@@ -3144,6 +3144,9 @@ mkdirs(char const *argname, bool ancestors)
 		** is checked anyway if the mkdir fails.
 		*/
 		if (mkdir(name, MKDIR_UMASK) != 0) {
+			/* For speed, skip itsdir if errno == EEXIST.  Since
+			   mkdirs is called only after open fails with ENOENT
+			   on a subfile, EEXIST implies itsdir here.  */
 			int err = errno;
 			if (err != EEXIST && !itsdir(name)) {
 				error(_("%s: Can't create directory %s: %s"),
-- 
2.7.4