Re: getgroups: test: =: unary operator expected

[Eric Blake]

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According to Jim Meyering on 10/22/2008 9:32 AM:
> To autoconf folks, I've attached the obvious patch below,
> and will push it some time tomorrow if no one objects.
> 
> * lib/autoconf/functions.m4 (AC_FUNC_GETGROUPS): Always define
> the shell variable, $ac_cv_func_getgroups_works.  Otherwise,
> if it set to "yes" in the environment and configure is run on
> a system like mingw that lacks the getgroups function, it would
> mistakenly define HAVE_GETGROUPS.  Reported by Simon Josefsson in
> <http://thread.gmane.org/gmane.comp.lib.gnulib.bugs/15354>.

Bah.  This is broken in autoconf; sorry for not catching it sooner.  In
the case where getgroups is available, the fact that
ac_cv_func_getgroups_works is predefined bypasses the attempt to even see
if it works.  Meanwhile, it exposed another gnulib bug:

getgroups.c: In function `rpl_getgroups':
getgroups.c:45: warning: implicit declaration of function `getgroups'

I'm committing these followups.  A nicer gnulib patch would involve
declaring rpl_getgroups in unistd.in.h, and modifying the unistd module to
be aware of whether rpl_getgroups is needed; but this smaller patch does
the trick for now.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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>From e2cdf35545f7834797a6d6dfb493f239d0fde479 Mon Sep 17 00:00:00 2001
From: Eric Blake <address@hidden>
Date: Fri, 24 Oct 2008 05:36:20 -0600
Subject: [PATCH] getgroups: fix compilation when getgroups is available

* lib/getgroups.c (includes): Include <unistd.h> for getgroups,
but with <config.h> override of getgroups disabled.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog       |    6 ++++++
 lib/getgroups.c |    7 ++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index cd514df..11a8b0d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2008-10-24  Eric Blake  <address@hidden>
+
+       getgroups: fix compilation when getgroups is available
+       * lib/getgroups.c (includes): Include <unistd.h> for getgroups,
+       but with <config.h> override of getgroups disabled.
+
 2008-10-23  Bruno Haible  <address@hidden>
 
        Define a dummy SA_NODEFER macro on Interix.
diff --git a/lib/getgroups.c b/lib/getgroups.c
index a8a225a..a4df7ab 100644
--- a/lib/getgroups.c
+++ b/lib/getgroups.c
@@ -1,6 +1,6 @@
 /* provide consistent interface to getgroups for systems that don't allow N==0
 
-   Copyright (C) 1996, 1999, 2003, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 1996, 1999, 2003, 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
@@ -19,10 +19,13 @@
 
 #include <config.h>
 
+#undef getgroups
+
 #include <stdio.h>
 #include <sys/types.h>
 #include <errno.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "xalloc.h"
 
@@ -38,8 +41,6 @@ rpl_getgroups (int n, GETGROUPS_T *group)
   GETGROUPS_T *gbuf;
   int saved_errno;
 
-#undef getgroups
-
   if (n != 0)
     return getgroups (n, group);
 
-- 
1.6.0.2

>From 21bd2e490b0804a0223b7044e89d5d31bd9f6476 Mon Sep 17 00:00:00 2001
From: Eric Blake <address@hidden>
Date: Fri, 24 Oct 2008 05:42:10 -0600
Subject: [PATCH] AC_FUNC_GETGROUPS: Revert regression.

* lib/autoconf/functions.m4 (AC_FUNC_GETGROUPS): Only set
ac_cv_func_getgroups_works=no when it is not available.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog                 |    6 ++++++
 lib/autoconf/functions.m4 |   15 +++++++++------
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index c8dca18..0a83589 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2008-10-24  Eric Blake  <address@hidden>
+
+       AC_FUNC_GETGROUPS: Revert regression.
+       * lib/autoconf/functions.m4 (AC_FUNC_GETGROUPS): Only set
+       ac_cv_func_getgroups_works=no when it is not available.
+
 2008-10-23  Eric Blake  <address@hidden>
 
        Whitespace cleanup.
diff --git a/lib/autoconf/functions.m4 b/lib/autoconf/functions.m4
index 3999134..f478ccc 100644
--- a/lib/autoconf/functions.m4
+++ b/lib/autoconf/functions.m4
@@ -619,7 +619,6 @@ if test $ac_cv_func_getgroups = no; then
   AC_CHECK_LIB(bsd, getgroups, [GETGROUPS_LIB=-lbsd])
 fi
 
-ac_cv_func_getgroups_works=no
 # Run the program to test the functionality of the system-supplied
 # getgroups function only if there is such a function.
 if test $ac_cv_func_getgroups = yes; then
@@ -627,12 +626,16 @@ if test $ac_cv_func_getgroups = yes; then
    [AC_RUN_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],
       [[/* On Ultrix 4.3, getgroups (0, 0) always fails.  */
        return getgroups (0, 0) == -1;]])],
-                 [ac_cv_func_getgroups_works=yes])
+                 [ac_cv_func_getgroups_works=yes],
+                 [ac_cv_func_getgroups_works=no],
+                 [ac_cv_func_getgroups_works=no])
    ])
-  if test $ac_cv_func_getgroups_works = yes; then
-    AC_DEFINE(HAVE_GETGROUPS, 1,
-             [Define to 1 if your system has a working `getgroups' function.])
-  fi
+else
+  ac_cv_func_getgroups_works=no
+fi
+if test $ac_cv_func_getgroups_works = yes; then
+  AC_DEFINE(HAVE_GETGROUPS, 1,
+           [Define to 1 if your system has a working `getgroups' function.])
 fi
 LIBS=$ac_save_LIBS
 ])# AC_FUNC_GETGROUPS
-- 
1.6.0.2