setenv, unsetenv fixes

[Bruno Haible]

Hi,

It was reported in [1] that there is a conflict between the unsetenv()
declarations on MacOS X and in gnulib under some conditions. The error message
is this:

  In file included from ../gnulib-lib/relocwrapper.c:56:
  ../gnulib-lib/setenv.h:47: error: conflicting types for `unsetenv'
  /usr/include/stdlib.h:248: error: previous declaration of `unsetenv'

This occurs in a package that uses the setenv() function but not the
unsetenv() function. setenv.h contains the declaration of unsetenv, but
since gl_FUNC_UNSETENV has not been called, HAVE_UNSETENV is not set; this
leads to the error.

The fix is to use a @GNULIB_UNSETENV@ macro. While at it, I also
  - move the declaration to <stdlib.h>, getting rid of setenv.h,
  - update the documentation about unsetenv,
  - split the module into a 'setenv' module and an 'unsetenv' module.

This is a backward-incompatible change; please see the NEWS entry.


2007-12-24  Bruno Haible  <address@hidden>

        Split setenv module into setenv and unsetenv. Get rid of setenv.h.
        * lib/setenv.h: Remove file.
        * lib/stdlib.in.h (setenv, unsetenv): New declarations, moved here from
        lib/setenv.h.
        * modules/setenv (Files): Remove lib/setenv.h, lib/unsetenv.c.
        (Depends-on): Add stdlib.
        (configure.ac): Invoke gl_STDLIB_MODULE_INDICATOR. Don't invoke
        gl_FUNC_UNSETENV.
        (Include): Replace setenv.h with <stdlib.h>.
        * modules/unsetenv: New file.
        * lib/setenv.c: Include <stdlib.h> first, after alloca.h.
        * lib/unsetenv.c: Include <stdlib.h> first.
        * m4/setenv.m4 (gl_FUNC_SETENV, gl_FUNC_SETENV_SEPARATE): Require
        gl_STDLIB_H_DEFAULTS. Conditionally set HAVE_SETENV to 0.
        (gl_FUNC_UNSETENV): Require gl_STDLIB_H_DEFAULTS. Conditionally set
        HAVE_UNSETENV to 0. Set VOID_UNSETENV as an AC_SUBSTed variable.
        * modules/stdlib (Makefile.am): Substitute also GNULIB_SETENV,
        HAVE_SETENV, GNULIB_UNSETENV, HAVE_UNSETENV, VOID_UNSETENV.
        * m4/stdlib_h.m4 (gl_STDLIB_H_DEFAULTS): Initialize GNULIB_SETENV,
        HAVE_SETENV, GNULIB_UNSETENV, HAVE_UNSETENV, VOID_UNSETENV.
        * doc/functions/unsetenv.texi: Update.
        * modules/xsetenv (Depends-on): Add unsetenv.
        * modules/getdate (Depends-on): Likewise.
        * lib/xsetenv.h: Include <stdlib.h> instead of setenv.h.
        * lib/xsetenv.c: Don't include setenv.h.
        * lib/getdate.y: Likewise.
        * lib/relocwrapper.c: Likewise.
        * modules/relocatable-prog-wrapper (Files): Remove lib/setenv.h.
        (Depends-on): Add stdlib.
        * NEWS: Mention the changes.
        Reported by Левашев Иван <address@hidden>.

*** NEWS.orig   2007-12-24 22:46:29.000000000 +0100
--- NEWS        2007-12-24 20:50:38.000000000 +0100
***************
*** 6,11 ****
--- 6,16 ----
  
  Date        Modules         Changes
  
+ 2007-12-24  setenv          The include file is changed from "setenv.h" to
+                             <stdlib.h>. Also, the unsetenv function is no
+                             longer declared in this module; use the 'unsetenv'
+                             module if you need it.
+ 
  2007-12-03  getpagesize     The include file is changed from "getpagesize.h"
                              to <unistd.h>.
  
*** doc/functions/unsetenv.texi.orig    2007-12-24 22:46:29.000000000 +0100
--- doc/functions/unsetenv.texi 2007-12-24 22:33:48.000000000 +0100
***************
*** 11,21 ****
  @item
  This function is missing on some platforms:
  AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 9, mingw, BeOS.
  @end itemize
  
  Portability problems not fixed by Gnulib:
  @itemize
- @item
- This function has the return type @samp{void} instead of @samp{int} on some
- platforms.
  @end itemize
--- 11,22 ----
  @item
  This function is missing on some platforms:
  AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 9, mingw, BeOS.
+ @item
+ This function has the return type @samp{void} instead of @samp{int} on some
+ platforms:
+ MacOS X 10.3, FreeBSD 6.0, NetBSD 1.6, OpenBSD 3.8, OSF/1 5.1.
  @end itemize
  
  Portability problems not fixed by Gnulib:
  @itemize
  @end itemize
*** lib/getdate.y.orig  2007-12-24 22:46:29.000000000 +0100
--- lib/getdate.y       2007-12-24 21:12:22.000000000 +0100
***************
*** 66,72 ****
  #include <stdlib.h>
  #include <string.h>
  
- #include "setenv.h"
  #include "xalloc.h"
  
  
--- 66,71 ----
*** lib/relocwrapper.c.orig     2007-12-24 22:46:29.000000000 +0100
--- lib/relocwrapper.c  2007-12-24 21:12:40.000000000 +0100
***************
*** 53,59 ****
  
  #include "progname.h"
  #include "relocatable.h"
- #include "setenv.h"
  #include "c-ctype.h"
  
  /* Return a copy of the filename, with an extra ".bin" at the end.
--- 53,58 ----
*** lib/setenv.c.orig   2007-12-24 22:46:29.000000000 +0100
--- lib/setenv.c        2007-12-24 20:51:48.000000000 +0100
***************
*** 19,30 ****
  #endif
  #include <alloca.h>
  
  #include <errno.h>
  #ifndef __set_errno
  # define __set_errno(ev) ((errno) = (ev))
  #endif
  
- #include <stdlib.h>
  #include <string.h>
  #if _LIBC || HAVE_UNISTD_H
  # include <unistd.h>
--- 19,32 ----
  #endif
  #include <alloca.h>
  
+ /* Specification.  */
+ #include <stdlib.h>
+ 
  #include <errno.h>
  #ifndef __set_errno
  # define __set_errno(ev) ((errno) = (ev))
  #endif
  
  #include <string.h>
  #if _LIBC || HAVE_UNISTD_H
  # include <unistd.h>
*** lib/stdlib.in.h.orig        2007-12-24 22:46:29.000000000 +0100
--- lib/stdlib.in.h     2007-12-24 20:46:23.000000000 +0100
***************
*** 1,6 ****
  /* A GNU-like <stdlib.h>.
  
!    Copyright (C) 1995, 2001-2002, 2006-2007 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
--- 1,6 ----
  /* A GNU-like <stdlib.h>.
  
!    Copyright (C) 1995, 2001-2004, 2006-2007 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
***************
*** 176,181 ****
--- 176,204 ----
  #endif
  
  
+ #if @GNULIB_SETENV@
+ # if address@hidden@
+ /* Set NAME to VALUE in the environment.
+    If REPLACE is nonzero, overwrite an existing value.  */
+ extern int setenv (const char *name, const char *value, int replace);
+ # endif
+ #endif
+ 
+ 
+ #if @GNULIB_UNSETENV@
+ # if @HAVE_UNSETENV@
+ #  if @VOID_UNSETENV@
+ /* On some systems, unsetenv() returns void.
+    This is the case for MacOS X 10.3, FreeBSD 4.8, NetBSD 1.6, OpenBSD 3.4.  
*/
+ #   define unsetenv(name) ((unsetenv)(name), 0)
+ #  endif
+ # else
+ /* Remove the variable NAME from the environment.  */
+ extern int unsetenv (const char *name);
+ # endif
+ #endif
+ 
+ 
  #ifdef __cplusplus
  }
  #endif
*** lib/unsetenv.c.orig 2007-12-24 22:46:29.000000000 +0100
--- lib/unsetenv.c      2007-12-24 20:52:18.000000000 +0100
***************
*** 1,4 ****
! /* Copyright (C) 1992,1995-1999,2000-2002,2005-2006 Free Software Foundation, 
Inc.
     This file is part of the GNU C Library.
  
     This program is free software: you can redistribute it and/or modify
--- 1,4 ----
! /* Copyright (C) 1992,1995-1999,2000-2002,2005-2007 Free Software Foundation, 
Inc.
     This file is part of the GNU C Library.
  
     This program is free software: you can redistribute it and/or modify
***************
*** 16,27 ****
  
  #include <config.h>
  
  #include <errno.h>
  #if !_LIBC
  # define __set_errno(ev) ((errno) = (ev))
  #endif
  
- #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  
--- 16,29 ----
  
  #include <config.h>
  
+ /* Specification.  */
+ #include <stdlib.h>
+ 
  #include <errno.h>
  #if !_LIBC
  # define __set_errno(ev) ((errno) = (ev))
  #endif
  
  #include <string.h>
  #include <unistd.h>
  
*** lib/xsetenv.c.orig  2007-12-24 22:46:29.000000000 +0100
--- lib/xsetenv.c       2007-12-24 21:12:55.000000000 +0100
***************
*** 21,27 ****
  
  #include <stdlib.h>
  
- #include "setenv.h"
  #include "error.h"
  #include "gettext.h"
  
--- 21,26 ----
*** lib/xsetenv.h.orig  2007-12-24 22:46:29.000000000 +0100
--- lib/xsetenv.h       2007-12-24 21:13:22.000000000 +0100
***************
*** 15,21 ****
     along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  
  /* Get unsetenv().  It can be used without error checking.  */
! #include "setenv.h"
  
  #ifdef __cplusplus
  extern "C" {
--- 15,21 ----
     along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  
  /* Get unsetenv().  It can be used without error checking.  */
! #include <stdlib.h>
  
  #ifdef __cplusplus
  extern "C" {
*** m4/setenv.m4.orig   2007-12-24 22:46:29.000000000 +0100
--- m4/setenv.m4        2007-12-24 21:05:01.000000000 +0100
***************
*** 1,4 ****
! # setenv.m4 serial 8
  dnl Copyright (C) 2001-2004, 2006-2007 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
--- 1,4 ----
! # setenv.m4 serial 9
  dnl Copyright (C) 2001-2004, 2006-2007 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
***************
*** 6,13 ****
--- 6,15 ----
  
  AC_DEFUN([gl_FUNC_SETENV],
  [
+   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
    AC_CHECK_FUNCS_ONCE([setenv])
    if test $ac_cv_func_setenv = no; then
+     HAVE_SETENV=0
      AC_LIBOBJ([setenv])
      gl_PREREQ_SETENV
    fi
***************
*** 16,29 ****
--- 18,37 ----
  # Like gl_FUNC_SETENV, except prepare for separate compilation (no AC_LIBOBJ).
  AC_DEFUN([gl_FUNC_SETENV_SEPARATE],
  [
+   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
    AC_CHECK_FUNCS_ONCE([setenv])
+   if test $ac_cv_func_setenv = no; then
+     HAVE_SETENV=0
+   fi
    gl_PREREQ_SETENV
  ])
  
  AC_DEFUN([gl_FUNC_UNSETENV],
  [
+   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
    AC_CHECK_FUNCS([unsetenv])
    if test $ac_cv_func_unsetenv = no; then
+     HAVE_UNSETENV=0
      AC_LIBOBJ([unsetenv])
      gl_PREREQ_UNSETENV
    else
***************
*** 40,46 ****
  #endif
  ], , gt_cv_func_unsetenv_ret='int', gt_cv_func_unsetenv_ret='void')])
      if test $gt_cv_func_unsetenv_ret = 'void'; then
!       AC_DEFINE(VOID_UNSETENV, 1, [Define if unsetenv() returns void, not 
int.])
      fi
    fi
  ])
--- 48,54 ----
  #endif
  ], , gt_cv_func_unsetenv_ret='int', gt_cv_func_unsetenv_ret='void')])
      if test $gt_cv_func_unsetenv_ret = 'void'; then
!       VOID_UNSETENV=1
      fi
    fi
  ])
*** m4/stdlib_h.m4.orig 2007-12-24 22:46:29.000000000 +0100
--- m4/stdlib_h.m4      2007-12-24 20:58:35.000000000 +0100
***************
*** 1,4 ****
! # stdlib_h.m4 serial 4
  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,
--- 1,4 ----
! # stdlib_h.m4 serial 5
  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,
***************
*** 26,37 ****
--- 26,42 ----
    GNULIB_MKDTEMP=0;       AC_SUBST([GNULIB_MKDTEMP])
    GNULIB_MKSTEMP=0;       AC_SUBST([GNULIB_MKSTEMP])
    GNULIB_PUTENV=0;        AC_SUBST([GNULIB_PUTENV])
+   GNULIB_SETENV=0;        AC_SUBST([GNULIB_SETENV])
+   GNULIB_UNSETENV=0;      AC_SUBST([GNULIB_UNSETENV])
    dnl Assume proper GNU behavior unless another module says otherwise.
    HAVE_CALLOC_POSIX=1;    AC_SUBST([HAVE_CALLOC_POSIX])
    HAVE_GETSUBOPT=1;       AC_SUBST([HAVE_GETSUBOPT])
    HAVE_MALLOC_POSIX=1;    AC_SUBST([HAVE_MALLOC_POSIX])
    HAVE_MKDTEMP=1;         AC_SUBST([HAVE_MKDTEMP])
    HAVE_REALLOC_POSIX=1;   AC_SUBST([HAVE_REALLOC_POSIX])
+   HAVE_SETENV=1;          AC_SUBST([HAVE_SETENV])
+   HAVE_UNSETENV=1;        AC_SUBST([HAVE_UNSETENV])
    REPLACE_MKSTEMP=0;      AC_SUBST([REPLACE_MKSTEMP])
    REPLACE_PUTENV=0;       AC_SUBST([REPLACE_PUTENV])
+   VOID_UNSETENV=0;        AC_SUBST([VOID_UNSETENV])
  ])
*** modules/getdate.orig        2007-12-24 22:46:29.000000000 +0100
--- modules/getdate     2007-12-24 21:17:57.000000000 +0100
***************
*** 15,20 ****
--- 15,21 ----
  intprops
  mktime
  setenv
+ unsetenv
  time
  verify
  xalloc
*** modules/relocatable-prog-wrapper.orig       2007-12-24 22:46:29.000000000 
+0100
--- modules/relocatable-prog-wrapper    2007-12-24 21:00:40.000000000 +0100
***************
*** 19,25 ****
  lib/malloca.c
  lib/relocatable.h
  lib/relocatable.c
- lib/setenv.h
  lib/setenv.c
  lib/strerror.c
  lib/c-ctype.h
--- 19,24 ----
***************
*** 38,43 ****
--- 37,43 ----
  pathmax
  ssize_t
  stdbool
+ stdlib
  unistd
  
  configure.ac:
*** modules/setenv.orig 2007-12-24 22:46:29.000000000 +0100
--- modules/setenv      2007-12-24 21:00:17.000000000 +0100
***************
*** 1,26 ****
  Description:
  setenv() function: set an environment variable.
- unsetenv() function: remove an environment variable.
  
  Files:
- lib/setenv.h
  lib/setenv.c
- lib/unsetenv.c
  m4/setenv.m4
  
  Depends-on:
  malloca
  alloca-opt
  unistd
  
  configure.ac:
  gl_FUNC_SETENV
! gl_FUNC_UNSETENV
  
  Makefile.am:
  
  Include:
! "setenv.h"
  
  License:
  LGPL
--- 1,24 ----
  Description:
  setenv() function: set an environment variable.
  
  Files:
  lib/setenv.c
  m4/setenv.m4
  
  Depends-on:
+ stdlib
  malloca
  alloca-opt
  unistd
  
  configure.ac:
  gl_FUNC_SETENV
! gl_STDLIB_MODULE_INDICATOR([setenv])
  
  Makefile.am:
  
  Include:
! <stdlib.h>
  
  License:
  LGPL
*** modules/stdlib.orig 2007-12-24 22:46:29.000000000 +0100
--- modules/stdlib      2007-12-24 20:56:50.000000000 +0100
***************
*** 30,42 ****
--- 30,47 ----
              -e 's|@''GNULIB_MKDTEMP''@|$(GNULIB_MKDTEMP)|g' \
              -e 's|@''GNULIB_MKSTEMP''@|$(GNULIB_MKSTEMP)|g' \
              -e 's|@''GNULIB_PUTENV''@|$(GNULIB_PUTENV)|g' \
+             -e 's|@''GNULIB_SETENV''@|$(GNULIB_SETENV)|g' \
+             -e 's|@''GNULIB_UNSETENV''@|$(GNULIB_UNSETENV)|g' \
              -e 's|@''HAVE_CALLOC_POSIX''@|$(HAVE_CALLOC_POSIX)|g' \
              -e 's|@''HAVE_GETSUBOPT''@|$(HAVE_GETSUBOPT)|g' \
              -e 's|@''HAVE_MALLOC_POSIX''@|$(HAVE_MALLOC_POSIX)|g' \
              -e 's|@''HAVE_MKDTEMP''@|$(HAVE_MKDTEMP)|g' \
              -e 's|@''HAVE_REALLOC_POSIX''@|$(HAVE_REALLOC_POSIX)|g' \
+             -e 's|@''HAVE_SETENV''@|$(HAVE_SETENV)|g' \
+             -e 's|@''HAVE_UNSETENV''@|$(HAVE_UNSETENV)|g' \
              -e 's|@''REPLACE_MKSTEMP''@|$(REPLACE_MKSTEMP)|g' \
              -e 's|@''REPLACE_PUTENV''@|$(REPLACE_PUTENV)|g' \
+             -e 's|@''VOID_UNSETENV''@|$(VOID_UNSETENV)|g' \
              -e '/definition of GL_LINK_WARNING/r $(LINK_WARNING_H)' \
              < $(srcdir)/stdlib.in.h; \
        } > address@hidden
*** modules/xsetenv.orig        2007-12-24 22:46:29.000000000 +0100
--- modules/xsetenv     2007-12-24 21:17:37.000000000 +0100
***************
*** 8,13 ****
--- 8,14 ----
  
  Depends-on:
  setenv
+ unsetenv
  error
  exit
  gettext-h
*** /dev/null   2003-09-23 19:59:22.000000000 +0200
--- modules/unsetenv    2007-12-24 21:00:21.000000000 +0100
***************
*** 0 ****
--- 1,26 ----
+ Description:
+ unsetenv() function: remove an environment variable.
+ 
+ Files:
+ lib/unsetenv.c
+ m4/setenv.m4
+ 
+ Depends-on:
+ stdlib
+ unistd
+ 
+ configure.ac:
+ gl_FUNC_UNSETENV
+ gl_STDLIB_MODULE_INDICATOR([unsetenv])
+ 
+ Makefile.am:
+ 
+ Include:
+ <stdlib.h>
+ 
+ License:
+ LGPL
+ 
+ Maintainer:
+ Bruno Haible
+ 


[1] http://lists.gnu.org/archive/html/bug-gnu-utils/2007-12/msg00001.html