Hello!
I'm planning to use Gnulib's `strftime' module on `master' to fix
portability problems related to `strftime', aka. #24130
(https://savannah.gnu.org/bugs/?24130). The good thing is that
`strftime' will now work the same regardless of the underlying libc.
The source modification is attached. For a discussion of
`nstrftime ()', see
http://thread.gmane.org/gmane.comp.lib.gnulib.bugs/14380 .
Please let me know if you think of a good reason to not do this,
otherwise I'll commit it within a week or so.
Thanks,
Ludo'.
>From 69f23174d313650ca8fb0f69ede45c48d7a26b05 Mon Sep 17 00:00:00 2001
From: =?utf-8?q?Ludovic=20Court=C3=A8s?= <[EMAIL PROTECTED]>
Date: Tue, 2 Sep 2008 21:24:53 +0200
Subject: [PATCH] Use Gnulib's `strftime' to address bug #24130.
* libguile/stime.c (scm_strftime): Use `nstrftime ()' from Gnulib.
This provides the same semantics on all platforms, thereby fixing
bug #24130.
* doc/ref/posix.texi (Time): Remove note about non-portable `%Z'
behavior. Describe the new, portable behavior.
* test-suite/tests/time.test ("strftime")["strftime %Z doesn't return
garbage"]: Reinstate.
["C99 %z format"](have-strftime-%z): Remove.
("GMT", "EST+5"): Don't use `have-strftime-%z'.
---
doc/ref/posix.texi | 25 +++----------------------
libguile/stime.c | 8 ++++----
test-suite/tests/time.test | 40 +++++++---------------------------------
3 files changed, 14 insertions(+), 59 deletions(-)
diff --git a/doc/ref/posix.texi b/doc/ref/posix.texi
index 34194fb..a91bdb9 100644
--- a/doc/ref/posix.texi
+++ b/doc/ref/posix.texi
@@ -1,6 +1,6 @@
@c -*-texinfo-*-
@c This is part of the GNU Guile Reference Manual.
[EMAIL PROTECTED] Copyright (C) 1996, 1997, 2000, 2001, 2002, 2003, 2004, 2006, 2007
[EMAIL PROTECTED] Copyright (C) 1996, 1997, 2000, 2001, 2002, 2003, 2004, 2006, 2007, 2008
@c Free Software Foundation, Inc.
@c See the file guile.texi for copying conditions.
@@ -1264,27 +1264,8 @@ formatting.
If @code{setlocale} has been called (@pxref{Locales}), month and day
names are from the current locale and in the locale character set.
-Note that @samp{%Z} might print the @code{tm:zone} in @var{tm} or it
-might print just the current zone (@code{tzset} above). A GNU system
-prints @code{tm:zone}, a strict C99 system like NetBSD prints the
-current zone. Perhaps in the future Guile will try to get
[EMAIL PROTECTED]:zone} used always.
[EMAIL PROTECTED]
[EMAIL PROTECTED] The issue in the above is not just whether tm_zone exists in
[EMAIL PROTECTED] struct tm, but whether libc feels it should read it. Being a
[EMAIL PROTECTED] non-C99 field, a strict C99 program won't know to set it, quite
[EMAIL PROTECTED] likely leaving garbage there. NetBSD, which has the field,
[EMAIL PROTECTED] therefore takes the view that it mustn't read it. See the PR
[EMAIL PROTECTED] about this at
[EMAIL PROTECTED]
[EMAIL PROTECTED] http://www.netbsd.org/cgi-bin/query-pr-single.pl?number=21722
[EMAIL PROTECTED]
[EMAIL PROTECTED] Uniformly making tm:zone used on all systems (all those which have
[EMAIL PROTECTED] %Z at all of course) might be nice (either mung TZ and tzset, or
[EMAIL PROTECTED] mung tzname[]). On the other hand it would make us do more than
[EMAIL PROTECTED] C99 says, and we really don't want to get intimate with the gory
[EMAIL PROTECTED] details of libc time funcs, no more than can be helped.
[EMAIL PROTECTED]
+Note that @samp{%Z} always ignores the @code{tm:zone} in @var{tm};
+instead it prints just the current zone (@code{tzset} above).
@end deffn
@deffn {Scheme Procedure} strptime format string
diff --git a/libguile/stime.c b/libguile/stime.c
index fa8b585..be5bf65 100644
--- a/libguile/stime.c
+++ b/libguile/stime.c
@@ -44,6 +44,7 @@
#include <stdio.h>
#include <errno.h>
+#include <strftime.h>
#include "libguile/_scm.h"
#include "libguile/async.h"
@@ -689,10 +690,9 @@ SCM_DEFINE (scm_strftime, "strftime", 2, 0, 0,
tzset ();
#endif
- /* POSIX says strftime returns 0 on buffer overrun, but old
- systems (i.e. libc 4 on GNU/Linux) might return `size' in that
- case. */
- while ((len = strftime (tbuf, size, myfmt, &t)) == 0 || len == size)
+ /* Use `nstrftime ()' from Gnulib, which supports all GNU extensions
+ supported by glibc. */
+ while ((len = nstrftime (tbuf, size, myfmt, &t, 0, 0)) == 0)
{
free (tbuf);
size *= 2;
diff --git a/test-suite/tests/time.test b/test-suite/tests/time.test
index ebc4499..d5639eb 100644
--- a/test-suite/tests/time.test
+++ b/test-suite/tests/time.test
@@ -1,7 +1,7 @@
;;;; time.test --- test suite for Guile's time functions -*- scheme -*-
;;;; Jim Blandy <[EMAIL PROTECTED]> --- June 1999, 2004
;;;;
-;;;; Copyright (C) 1999, 2004, 2006, 2007 Free Software Foundation, Inc.
+;;;; Copyright (C) 1999, 2004, 2006, 2007, 2008 Free Software Foundation, Inc.
;;;;
;;;; This program is free software; you can redistribute it and/or modify
;;;; it under the terms of the GNU General Public License as published by
@@ -196,44 +196,19 @@
(with-test-prefix "strftime"
- ;; Note we must force isdst to get the ZOW zone name out of %Z on HP-UX.
- ;; If localtime is in daylight savings then it will decide there's no
- ;; daylight savings zone name for the fake ZOW, and come back empty.
- ;;
- ;; This test is disabled because on NetBSD %Z doesn't look at the tm_zone
- ;; field in struct tm passed by guile. That behaviour is reasonable
- ;; enough since that field is not in C99 so a C99 program won't know it
- ;; has to be set. For the details on that see
- ;;
- ;; http://www.netbsd.org/cgi-bin/query-pr-single.pl?number=21722
- ;;
- ;; Not sure what to do about this in guile, it'd be nice for %Z to look at
- ;; tm:zone everywhere.
- ;;
- ;;
- ;; (pass-if "strftime %Z doesn't return garbage"
- ;; (let ((t (localtime (current-time))))
- ;; (set-tm:zone t "ZOW")
- ;; (set-tm:isdst t 0)
- ;; (string=? (strftime "%Z" t)
- ;; "ZOW")))
+ (pass-if "strftime %Z doesn't return garbage"
+ (let ((t (localtime (current-time))))
+ (set-tm:zone t "ZOW")
+ (set-tm:isdst t 0)
+ (string=? (strftime "%Z" t)
+ "ZOW")))
(with-test-prefix "C99 %z format"
- ;; C99 spec is empty string if no zone determinable
- ;;
- ;; on pre-C99 systems not sure what to expect if %z unsupported, probably
- ;; "%z" unchanged in C99 if timezone
- ;;
- (define have-strftime-%z
- (not (member (strftime "%z" (gmtime 0))
- '("" "%z"))))
-
;; %z here is quite possibly affected by the same tm:gmtoff vs current
;; zone as %Z above is, so in the following tests we make them the same.
(pass-if "GMT"
- (or have-strftime-%z (throw 'unsupported))
(putenv "TZ=GMT+0")
(tzset)
(let ((tm (localtime 86400)))
@@ -243,7 +218,6 @@
;; because we didn't adjust for tm:gmtoff being west of Greenwich versus
;; tm_gmtoff being east of Greenwich
(pass-if "EST+5"
- (or have-strftime-%z (throw 'unsupported))
(putenv "TZ=EST+5")
(tzset)
(let ((tm (localtime 86400)))
--
1.6.0
