From e231da4fb2beb17c60b4b1a5c276366d6a6e433f Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Mon, 23 Oct 2017 17:58:36 -0700
Subject: [PATCH] Port zdump to C90 + snprintf
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Problem reported by Jon Skeet in:
https://mm.icann.org/pipermail/tz/2017-October/025362.html
* NEWS: Mention this.
* zdump.c (my_snprintf): New macro or function.  If a macro, it is
just snprintf.  If a function, it is the same as the old snprintf
static function, with an ATTRIBUTE_FORMAT to pacify modern GCC.
All uses of snprintf changed to use my_snprintf.  This way,
installers don’t need to specify -DHAVE_SNPRINTF if they are using
a pre-C99 compiler with a library that has snprintf.

Upstream-Status: Backport
Signed-off-by: Armin Kuster <akuster@mvista.com>

---
 NEWS    |  4 ++++
 zdump.c | 29 ++++++++++++++++-------------
 2 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/NEWS b/NEWS
index 75ab095..dea08b8 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,10 @@ Unreleased, experimental changes
     The Makefile now quotes values like BACKWARD more carefully when
     passing them to the shell.  (Problem reported by Zefram.)
 
+    Builders no longer need to specify -DHAVE_SNPRINTF on platforms
+    that have snprintf and use pre-C99 compilers.  (Problem reported
+    by Jon Skeet.)
+
 
 Release 2017c - 2017-10-20 14:49:34 -0700
 
diff --git a/zdump.c b/zdump.c
index 8e3bf3e..d4e6084 100644
--- a/zdump.c
+++ b/zdump.c
@@ -795,12 +795,14 @@ show(timezone_t tz, char *zone, time_t t, bool v)
 		abbrok(abbr(tmp), zone);
 }
 
-#if !HAVE_SNPRINTF
+#if HAVE_SNPRINTF
+# define my_snprintf snprintf
+#else
 # include <stdarg.h>
 
 /* A substitute for snprintf that is good enough for zdump.  */
-static int
-snprintf(char *s, size_t size, char const *format, ...)
+static int ATTRIBUTE_FORMAT((printf, 3, 4))
+my_snprintf(char *s, size_t size, char const *format, ...)
 {
   int n;
   va_list args;
@@ -839,10 +841,10 @@ format_local_time(char *buf, size_t size, struct tm const *tm)
 {
   int ss = tm->tm_sec, mm = tm->tm_min, hh = tm->tm_hour;
   return (ss
-	  ? snprintf(buf, size, "%02d:%02d:%02d", hh, mm, ss)
+	  ? my_snprintf(buf, size, "%02d:%02d:%02d", hh, mm, ss)
 	  : mm
-	  ? snprintf(buf, size, "%02d:%02d", hh, mm)
-	  : snprintf(buf, size, "%02d", hh));
+	  ? my_snprintf(buf, size, "%02d:%02d", hh, mm)
+	  : my_snprintf(buf, size, "%02d", hh));
 }
 
 /* Store into BUF, of size SIZE, a formatted UTC offset for the
@@ -877,10 +879,10 @@ format_utc_offset(char *buf, size_t size, struct tm const *tm, time_t t)
   mm = off / 60 % 60;
   hh = off / 60 / 60;
   return (ss || 100 <= hh
-	  ? snprintf(buf, size, "%c%02ld%02d%02d", sign, hh, mm, ss)
+	  ? my_snprintf(buf, size, "%c%02ld%02d%02d", sign, hh, mm, ss)
 	  : mm
-	  ? snprintf(buf, size, "%c%02ld%02d", sign, hh, mm)
-	  : snprintf(buf, size, "%c%02ld", sign, hh));
+	  ? my_snprintf(buf, size, "%c%02ld%02d", sign, hh, mm)
+	  : my_snprintf(buf, size, "%c%02ld", sign, hh));
 }
 
 /* Store into BUF (of size SIZE) a quoted string representation of P.
@@ -983,15 +985,16 @@ istrftime(char *buf, size_t size, char const *time_fmt,
 	    for (abp = ab; is_alpha(*abp); abp++)
 	      continue;
 	    len = (!*abp && *ab
-		   ? snprintf(b, s, "%s", ab)
+		   ? my_snprintf(b, s, "%s", ab)
 		   : format_quoted_string(b, s, ab));
 	    if (s <= len)
 	      return false;
 	    b += len, s -= len;
 	  }
-	  formatted_len = (tm->tm_isdst
-			   ? snprintf(b, s, &"\t\t%d"[show_abbr], tm->tm_isdst)
-			   : 0);
+	  formatted_len
+	    = (tm->tm_isdst
+	       ? my_snprintf(b, s, &"\t\t%d"[show_abbr], tm->tm_isdst)
+	       : 0);
 	}
 	break;
       }
-- 
2.7.4

