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Re: fflush after ungetc
From: |
Bruno Haible |
Subject: |
Re: fflush after ungetc |
Date: |
Sat, 29 Mar 2008 12:59:34 +0100 |
User-agent: |
KMail/1.5.4 |
Eric Blake wrote:
> Cygwin 1.5.25-11 implements 1a+2a, and does not require an fflush
> replacement by any of the current tests in fflush.m4. Therefore, cygwin
> fails test-fflush2.c
> ...
> At this point, I would even be happy with a solution that enforces 1a ...
Oops, you are right. My previous commit on this topic was incomplete:
- My mail [1] said that gnulib implements 1b+2b, but the unit test only
verifies 2b, not case 1.
- On glibc systems, the behaviour is 1a+2x (neither of 2a,2b,2c), and
fflush is not replaced, so the resulting behaviour is 1a+2x, not 1b+2b.
- On Cygwin 1.5.25-11, as you say, the behaviour is 1a+2a, and fflush is
not replaced, so the resulting behaviour is 1a+2a, not 1b+2b.
[1] http://lists.gnu.org/archive/html/bug-gnulib/2008-03/msg00132.html
At this point, waiting for a resolution by the Austin Group (Geoff Clare's
mail is an important opinion, but not yet a decision), I prefer to not change
the code, but just disable the test.
Bruno
2008-03-29 Bruno Haible <address@hidden>
* tests/test-fflush2.c (main): Temporarily disable the contents of
this test.
* m4/fflush.m4 (gl_FUNC_FFLUSH): Add a TODO.
Reported by Eric Blake.
*** tests/test-fflush2.c.orig 2008-03-29 12:44:08.000000000 +0100
--- tests/test-fflush2.c 2008-03-29 12:43:29.000000000 +0100
***************
*** 48,53 ****
--- 48,62 ----
int
main (int argc, char **argv)
{
+ #if 0
+ /* Check fflush after a backup ungetc() call. This is case 1 in terms of
+ <http://lists.gnu.org/archive/html/bug-gnulib/2008-03/msg00131.html>.
+ The Austin Group has not yet decided how this should behave. */
+ #endif
+ #if 0
+ /* Check fflush after a non-backup ungetc() call. This is case 1 in terms
of
+ <http://lists.gnu.org/archive/html/bug-gnulib/2008-03/msg00131.html>.
+ The Austin Group has not yet decided how this should behave. */
/* Check that fflush after a non-backup ungetc() call discards the ungetc
buffer. This is mandated by POSIX
<http://www.opengroup.org/susv3/functions/ungetc.html>:
***************
*** 73,78 ****
--- 82,88 ----
c = fgetc (stdin);
ASSERT (c == '/');
+ #endif
return 0;
}
*** m4/fflush.m4.orig 2008-03-29 12:44:08.000000000 +0100
--- m4/fflush.m4 2008-03-29 12:40:33.000000000 +0100
***************
*** 1,6 ****
! # fflush.m4 serial 4
! # Copyright (C) 2007 Free Software Foundation, Inc.
# This file is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.
--- 1,6 ----
! # fflush.m4 serial 5
! # Copyright (C) 2007-2008 Free Software Foundation, Inc.
# This file is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.
***************
*** 21,28 ****
#include <unistd.h>
]], [[FILE *f = fopen ("conftest.txt", "r");
char buffer[10];
! int fd = fileno (f);
! if (!f || 0 > fd || fread (buffer, 1, 5, f) != 5)
return 2;
/* For deterministic results, ensure f read a bigger buffer. */
if (lseek (fd, 0, SEEK_CUR) == 5)
--- 21,31 ----
#include <unistd.h>
]], [[FILE *f = fopen ("conftest.txt", "r");
char buffer[10];
! int fd;
! if (f == NULL)
! return 1;
! fd = fileno (f);
! if (fd < 0 || fread (buffer, 1, 5, f) != 5)
return 2;
/* For deterministic results, ensure f read a bigger buffer. */
if (lseek (fd, 0, SEEK_CUR) == 5)
***************
*** 30,36 ****
/* POSIX requires fflush-fseek to set file offset of fd. */
if (fflush (f) != 0 || fseek (f, 0, SEEK_CUR) != 0)
return 4;
! return !(lseek (fd, 0, SEEK_CUR) == 5);
]])], [gl_cv_func_fflush_stdin=yes], [gl_cv_func_fflush_stdin=no],
[dnl Pessimistically assume fflush is broken. This is wrong for
dnl at least glibc and cygwin; but lib/fflush.c takes this into account.
--- 33,43 ----
/* POSIX requires fflush-fseek to set file offset of fd. */
if (fflush (f) != 0 || fseek (f, 0, SEEK_CUR) != 0)
return 4;
! if (lseek (fd, 0, SEEK_CUR) != 5)
! return 5;
! /* TODO: Verify behaviour of fflush after ungetc, see
!
<http://lists.gnu.org/archive/html/bug-gnulib/2008-03/msg00131.html>. */
! return 0;
]])], [gl_cv_func_fflush_stdin=yes], [gl_cv_func_fflush_stdin=no],
[dnl Pessimistically assume fflush is broken. This is wrong for
dnl at least glibc and cygwin; but lib/fflush.c takes this into account.
- Re: fflush after ungetc, (continued)
- Message not available
- Re: fflush after ungetc, Eric Blake, 2008/03/26
- Re: fflush after ungetc, Bruno Haible, 2008/03/06
- Re: fflush after ungetc, Eric Blake, 2008/03/06
- Re: fflush after ungetc, Bruno Haible, 2008/03/09
- Re: fflush after ungetc, Eric Blake, 2008/03/29
- Re: fflush after ungetc, Eric Blake, 2008/03/29
- Re: fflush after ungetc,
Bruno Haible <=
- Re: fflush after ungetc, Eric Blake, 2008/03/29
- Re: freadseek, Bruno Haible, 2008/03/30
- Re: fflush after ungetc, Bruno Haible, 2008/03/30
- Re: Cygwin ftell bug, Bruno Haible, 2008/03/06