new module 'ftell' (was: Re: mingw lseek bug)

[Bruno Haible]

Eric Blake wrote:
> --- doc/functions/ftell.texi  1 May 2007 15:11:38 -0000       1.1
> +++ doc/functions/ftell.texi  24 May 2007 16:21:36 -0000
> @@ -4,10 +4,12 @@
>  
>  POSIX specification: @url{http://www.opengroup.org/susv3xsh/ftell.html}
>  
> -Gnulib module: ---
> +Gnulib module: ftello
>  
>  Portability problems fixed by Gnulib:
>  @itemize
> address@hidden
> +This function mistakenly succeeds on non-seekable files: mingw.
>  @end itemize
>  
>  Portability problems not fixed by Gnulib:

Likewise, this requires an 'ftell' module.

2007-05-28  Bruno Haible  <address@hidden>

        * lib/ftell.c: New file.
        * modules/ftell: New file.
        * m4/ftell.m4: New file.
        * doc/functions/ftell.texi: Update.
        * m4/stdio_h.m4 (gl_STDIO_H_DEFAULTS): Set also GNULIB_FTELL,
        REPLACE_FTELL.
        * lib/stdio_.h (rpl_ftell): New declaration.
        * modules/stdio (Makefile.am): Substitute also GNULIB_FTELL,
        REPLACE_FTELL.

=========================== lib/ftell.c ==============================
/* An ftell() function that works around platform bugs.
   Copyright (C) 2007 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
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License along
   with this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

#include <config.h>

/* Specification.  */
#include <stdio.h>

#include <errno.h>
/* Get off_t.  */
#include <unistd.h>

long
ftell (FILE *fp)
{
  /* Use the replacement ftello function with all its workarounds.  */
  off_t offset = ftello (fp);
  if (offset == (long)offset)
    return (long)offset;
  else
    {
      errno = EOVERFLOW;
      return -1;
    }
}
=========================== modules/ftell ============================
Description:
ftell() function: Retrieve the position of a FILE stream.

Files:
lib/ftell.c
m4/ftell.m4

Depends-on:
ftello
stdio

configure.ac:
gl_FUNC_FTELL
gl_STDIO_MODULE_INDICATOR([ftell])

Makefile.am:

Include:
<stdio.h>

License:
LGPL

Maintainer:
Bruno Haible

=========================== m4/ftell.m4 ==============================
# ftell.m4 serial 1
dnl Copyright (C) 2007 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

AC_DEFUN([gl_FUNC_FTELL],
[
  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
  AC_REQUIRE([gl_FUNC_TELLO])
  dnl When ftello needs fixes, ftell needs them too.
  if test $REPLACE_FTELLO != 0; then
    AC_LIBOBJ([ftell])
    REPLACE_FTELL=1
  fi
])
======================================================================
*** doc/functions/ftell.texi    28 May 2007 14:08:37 -0000      1.3
--- doc/functions/ftell.texi    28 May 2007 15:08:46 -0000
***************
*** 4,15 ****
  
  POSIX specification: @url{http://www.opengroup.org/susv3xsh/ftell.html}
  
! Gnulib module: ftello
  
  Portability problems fixed by Gnulib:
  @itemize
  @item
! This function mistakenly succeeds on non-seekable files: mingw.
  @end itemize
  
  Portability problems not fixed by Gnulib:
--- 4,15 ----
  
  POSIX specification: @url{http://www.opengroup.org/susv3xsh/ftell.html}
  
! Gnulib module: ftell
  
  Portability problems fixed by Gnulib:
  @itemize
  @item
! This function mistakenly succeeds on pipes on some platforms: mingw.
  @end itemize
  
  Portability problems not fixed by Gnulib:
*** m4/stdio_h.m4       28 May 2007 14:51:49 -0000      1.15
--- m4/stdio_h.m4       28 May 2007 15:08:46 -0000
***************
*** 32,37 ****
--- 32,38 ----
    GNULIB_VASPRINTF=0;      AC_SUBST([GNULIB_VASPRINTF])
    GNULIB_FSEEK=0;          AC_SUBST([GNULIB_FSEEK])
    GNULIB_FSEEKO=0;         AC_SUBST([GNULIB_FSEEKO])
+   GNULIB_FTELL=0;          AC_SUBST([GNULIB_FTELL])
    GNULIB_FTELLO=0;         AC_SUBST([GNULIB_FTELLO])
    GNULIB_FFLUSH=0;         AC_SUBST([GNULIB_FFLUSH])
    dnl Assume proper GNU behavior unless another module says otherwise.
***************
*** 52,57 ****
--- 53,59 ----
    REPLACE_FSEEK=0;         AC_SUBST([REPLACE_FSEEK])
    HAVE_FTELLO=1;           AC_SUBST([HAVE_FTELLO])
    REPLACE_FTELLO=0;        AC_SUBST([REPLACE_FTELLO])
+   REPLACE_FTELL=0;         AC_SUBST([REPLACE_FTELL])
    REPLACE_FFLUSH=0;        AC_SUBST([REPLACE_FFLUSH])
  ])
  
*** lib/stdio_.h        28 May 2007 14:51:49 -0000      1.29
--- lib/stdio_.h        28 May 2007 15:08:46 -0000
***************
*** 268,274 ****
      ftello (f))
  #endif
  
! #if defined GNULIB_POSIXCHECK
  # ifndef ftell
  #  define ftell(f) \
       (GL_LINK_WARNING ("ftell cannot handle files larger than 4 GB " \
--- 268,286 ----
      ftello (f))
  #endif
  
! #if @GNULIB_FTELL@ && @REPLACE_FTELL@
! extern long rpl_ftell (FILE *fp);
! # undef ftell
! # if GNULIB_POSIXCHECK
! #  define ftell(f) \
!      (GL_LINK_WARNING ("ftell cannot handle files larger than 4 GB " \
!                        "on 32-bit platforms - " \
!                        "use ftello function for handling of large files"), \
!       rpl_ftell (f))
! # else
! #  define ftell rpl_ftell
! # endif
! #elif defined GNULIB_POSIXCHECK
  # ifndef ftell
  #  define ftell(f) \
       (GL_LINK_WARNING ("ftell cannot handle files larger than 4 GB " \
*** modules/stdio       28 May 2007 14:51:49 -0000      1.17
--- modules/stdio       28 May 2007 15:08:46 -0000
***************
*** 33,38 ****
--- 33,39 ----
              -e 's|@''GNULIB_VASPRINTF''@|$(GNULIB_VASPRINTF)|g' \
              -e 's|@''GNULIB_FSEEK''@|$(GNULIB_FSEEK)|g' \
              -e 's|@''GNULIB_FSEEKO''@|$(GNULIB_FSEEKO)|g' \
+             -e 's|@''GNULIB_FTELL''@|$(GNULIB_FTELL)|g' \
              -e 's|@''GNULIB_FTELLO''@|$(GNULIB_FTELLO)|g' \
              -e 's|@''GNULIB_FFLUSH''@|$(GNULIB_FFLUSH)|g' \
              -e 's|@''REPLACE_FPRINTF''@|$(REPLACE_FPRINTF)|g' \
***************
*** 50,55 ****
--- 51,57 ----
              -e 's|@''REPLACE_FSEEKO''@|$(REPLACE_FSEEKO)|g' \
              -e 's|@''REPLACE_FSEEK''@|$(REPLACE_FSEEK)|g' \
              -e 's|@''REPLACE_FTELLO''@|$(REPLACE_FTELLO)|g' \
+             -e 's|@''REPLACE_FTELL''@|$(REPLACE_FTELL)|g' \
              -e 's|@''REPLACE_FFLUSH''@|$(REPLACE_FFLUSH)|g' \
              -e '/definition of GL_LINK_WARNING/r $(LINK_WARNING_H)' \
              < $(srcdir)/stdio_.h; \