Dear Ralf,
thank you for your very much detailed answer, it was helpful!
Ralf Wildenhues wrote:
* Michael Grünewald wrote on Fri, Nov 12, 2010 at 09:51:55PM CET:
AC_DEFUN([AC_PROG_ID],
[AC_CACHE_CHECK([for id that handles -g, -u and -n], ac_cv_path_ID,
[ac_cv_path_ID=no
for ac_cv_path_ID_v in id /usr/xpg4/bin/id 'command -p id'; do
if test "$ac_cv_path_ID" = "no"; then
( $ac_cv_path_ID_v -g&& $ac_cv_path_ID_v -g -n&&
$ac_cv_path_ID_v -u&& $ac_cv_path_ID_v -u -n ) 2>&- 1>&-&&
ac_cv_path_ID="$ac_cv_path_ID_v"
fi
done;])
ID="$ac_cv_path_ID"
AC_SUBST([ID])
])
-8<---
Redirect standard output and standard error to /dev/null rather than
closing them; if you close them the program gets an error when writing
to the file descriptor, and those 'id' programs which pass the test are
in fact the buggier ones. ;-)
Indeed you are right! I modified the snippet according to your
recommandataion and it gives satisfying results now.
The standard Autoconf way to write this would be to use AC_CHECK_PROG or
AC_PATH_PROG rather than open-coding it;
I found description for these macros in the info manual for Autoconf,
but I could not figure out how to use them in my situation. It seems to
me that these macros check for the availablity of some program while I
need to choose between several plausbile alternatives, given that they
do not all have the same capabilities.
For me, the problem is that `id -u -n' and `id -g -n' do not work on the
Solaris installations I used: I had to use `/usr/xpg4/bin/id' or
`command -p id' instead.
Your help was much appreciated,
thank you!
Note: the `reply to all' in my mailer did not add your name in the
recipients list. Is this a broken behaviour of my mailer or did you set
some headers to require this?
--
Michael
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