new module 'fclose'

[Bruno Haible]

We're overriding close(). But the system's fclose(), when called on a FILE
stream that was created with fdopen() from a socket descriptor, will not
invoke our overridden close(). So we have to override fclose() as well.

I'm committing this. It has a circular dependency between the modules
'close' and 'fclose'. That seems the safest to me.

2008-10-11  Bruno Haible  <address@hidden>

        New module 'fclose'.
        * modules/fclose: New file.
        * lib/stdio.in.h (fclose): New declaration.
        * lib/fclose.c: New file.
        * m4/fclose.m4: New file.
        * m4/stdio_h.m4 (gl_STDIO_H_DEFAULTS): Initialize GNULIB_FCLOSE,
        REPLACE_FCLOSE.
        * m4/close.m4 (gl_REPLACE_CLOSE): Invoke gl_REPLACE_FCLOSE.
        * modules/stdio (Makefile.am): Substitute GNULIB_FCLOSE,
        REPLACE_FCLOSE.
        * modules/close (Depends-on): fclose.
        * doc/posix-functions/fclose.texi: Mention the problem on Windows.

========================== modules/fclose ===============================
Description:
fclose() function: close a stream.

Files:
lib/fclose.c
m4/fclose.m4

Depends-on:
stdio
close

configure.ac:
gl_FUNC_FCLOSE
gl_STDIO_MODULE_INDICATOR([fclose])

Makefile.am:

Include:
<stdio.h>

License:
LGPLv2+

Maintainer:
Bruno Haible

========================== lib/fclose.c =================================
/* close replacement.
   Copyright (C) 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
   the Free Software Foundation; either version 3 of the License, 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, see <http://www.gnu.org/licenses/>.  */

#include <config.h>

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

#include <errno.h>
#include <unistd.h>

/* Override fclose() to call the overridden close().  */

int
rpl_fclose (FILE *fp)
#undef fclose
{
  int saved_errno = 0;

  if (fflush (fp))
    saved_errno = errno;

  if (close (fileno (fp)) < 0 && saved_errno == 0)
    saved_errno = errno;

  fclose (fp); /* will fail with errno = EBADF */

  if (saved_errno != 0)
    {
      errno = saved_errno;
      return EOF;
    }
  return 0;
}
========================== m4/fclose.m4 =================================
# fclose.m4 serial 1
dnl Copyright (C) 2008 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_FCLOSE],
[
])

AC_DEFUN([gl_REPLACE_FCLOSE],
[
  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
  if test $REPLACE_FCLOSE != 1; then
    AC_LIBOBJ([fclose])
  fi
  REPLACE_FCLOSE=1
])
=========================================================================
*** lib/stdio.in.h.orig 2008-10-11 14:03:09.000000000 +0200
--- lib/stdio.in.h      2008-10-11 12:47:44.000000000 +0200
***************
*** 373,378 ****
--- 373,393 ----
      fflush (f))
  #endif
  
+ #if @GNULIB_FCLOSE@
+ # if @REPLACE_FCLOSE@
+ #  define fclose rpl_fclose
+   /* Close STREAM and its underlying file descriptor.  */
+ extern int fclose (FILE *stream);
+ # endif
+ #elif defined GNULIB_POSIXCHECK
+ # undef fclose
+ # define fclose(f) \
+    (GL_LINK_WARNING ("fclose is not always POSIX compliant - " \
+                      "use gnulib module fclose for portable " \
+                      "POSIX compliance"), \
+     fclose (f))
+ #endif
+ 
  #if @GNULIB_FPUTC@ && @REPLACE_STDIO_WRITE_FUNCS@ && @GNULIB_STDIO_H_SIGPIPE@
  # undef fputc
  # define fputc rpl_fputc
*** m4/stdio_h.m4.orig  2008-10-11 14:03:09.000000000 +0200
--- m4/stdio_h.m4       2008-10-11 12:49:26.000000000 +0200
***************
*** 1,4 ****
! # stdio_h.m4 serial 13
  dnl Copyright (C) 2007-2008 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
--- 1,4 ----
! # stdio_h.m4 serial 14
  dnl Copyright (C) 2007-2008 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
***************
*** 63,68 ****
--- 63,69 ----
    GNULIB_FTELL=0;                AC_SUBST([GNULIB_FTELL])
    GNULIB_FTELLO=0;               AC_SUBST([GNULIB_FTELLO])
    GNULIB_FFLUSH=0;               AC_SUBST([GNULIB_FFLUSH])
+   GNULIB_FCLOSE=0;               AC_SUBST([GNULIB_FCLOSE])
    GNULIB_FPUTC=0;                AC_SUBST([GNULIB_FPUTC])
    GNULIB_PUTC=0;                 AC_SUBST([GNULIB_PUTC])
    GNULIB_PUTCHAR=0;              AC_SUBST([GNULIB_PUTCHAR])
***************
*** 98,103 ****
--- 99,105 ----
    REPLACE_FTELLO=0;              AC_SUBST([REPLACE_FTELLO])
    REPLACE_FTELL=0;               AC_SUBST([REPLACE_FTELL])
    REPLACE_FFLUSH=0;              AC_SUBST([REPLACE_FFLUSH])
+   REPLACE_FCLOSE=0;              AC_SUBST([REPLACE_FCLOSE])
    HAVE_DECL_GETDELIM=1;          AC_SUBST([HAVE_DECL_GETDELIM])
    HAVE_DECL_GETLINE=1;           AC_SUBST([HAVE_DECL_GETLINE])
    REPLACE_GETLINE=0;             AC_SUBST([REPLACE_GETLINE])
*** m4/close.m4.orig    2008-10-11 14:03:09.000000000 +0200
--- m4/close.m4 2008-10-11 14:02:55.000000000 +0200
***************
*** 1,4 ****
! # close.m4 serial 1
  dnl Copyright (C) 2008 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
--- 1,4 ----
! # close.m4 serial 2
  dnl Copyright (C) 2008 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
***************
*** 21,24 ****
--- 21,25 ----
      AC_LIBOBJ([close])
    fi
    REPLACE_CLOSE=1
+   gl_REPLACE_FCLOSE
  ])
*** modules/stdio.orig  2008-10-11 14:03:09.000000000 +0200
--- modules/stdio       2008-10-11 12:48:51.000000000 +0200
***************
*** 46,51 ****
--- 46,52 ----
              -e 's|@''GNULIB_FTELL''@|$(GNULIB_FTELL)|g' \
              -e 's|@''GNULIB_FTELLO''@|$(GNULIB_FTELLO)|g' \
              -e 's|@''GNULIB_FFLUSH''@|$(GNULIB_FFLUSH)|g' \
+             -e 's|@''GNULIB_FCLOSE''@|$(GNULIB_FCLOSE)|g' \
              -e 's|@''GNULIB_FPUTC''@|$(GNULIB_FPUTC)|g' \
              -e 's|@''GNULIB_PUTC''@|$(GNULIB_PUTC)|g' \
              -e 's|@''GNULIB_PUTCHAR''@|$(GNULIB_PUTCHAR)|g' \
***************
*** 78,83 ****
--- 79,85 ----
              -e 's|@''REPLACE_FTELLO''@|$(REPLACE_FTELLO)|g' \
              -e 's|@''REPLACE_FTELL''@|$(REPLACE_FTELL)|g' \
              -e 's|@''REPLACE_FFLUSH''@|$(REPLACE_FFLUSH)|g' \
+             -e 's|@''REPLACE_FCLOSE''@|$(REPLACE_FCLOSE)|g' \
              -e 's|@''HAVE_DECL_GETDELIM''@|$(HAVE_DECL_GETDELIM)|g' \
              -e 's|@''HAVE_DECL_GETLINE''@|$(HAVE_DECL_GETLINE)|g' \
              -e 's|@''REPLACE_GETLINE''@|$(REPLACE_GETLINE)|g' \
*** modules/close.orig  2008-10-11 14:03:09.000000000 +0200
--- modules/close       2008-10-11 13:44:12.000000000 +0200
***************
*** 7,12 ****
--- 7,13 ----
  
  Depends-on:
  unistd
+ fclose
  
  configure.ac:
  gl_FUNC_CLOSE
*** doc/posix-functions/fclose.texi.orig        2008-10-11 14:03:09.000000000 
+0200
--- doc/posix-functions/fclose.texi     2008-10-11 12:30:35.000000000 +0200
***************
*** 4,13 ****
  
  POSIX specification: @url{http://www.opengroup.org/susv3xsh/fclose.html}
  
! Gnulib module: ---
  
  Portability problems fixed by Gnulib:
  @itemize
  @end itemize
  
  Portability problems not fixed by Gnulib:
--- 4,17 ----
  
  POSIX specification: @url{http://www.opengroup.org/susv3xsh/fclose.html}
  
! Gnulib module: fclose
  
  Portability problems fixed by Gnulib:
  @itemize
+ @item
+ On Windows platforms (excluding Cygwin), @code{socket} and @code{accept}
+ followed by @code{fdopen} do not return streams that can be closed by
+ @code{fclose}.
  @end itemize
  
  Portability problems not fixed by Gnulib: