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AX_SYS_PERLSHARPBANG
1.1 (2004/03/01) 0.5.57 : Installed_Packages
Soren Andersen <somian *AT* pobox |DOT| com>
Note: The macro allows for the possibility (expected to be seldom used) of an explicit user override (the "user" being the operator executing the final 'configure' script, in this context) by making the option argument like:
--with-perl-shebang='#! /my/funky/perlpath' # OR
--with-perl-shebang='/my/funky/perlpath' # we just throw away the #! anyway
# bec it must be absent in Makefile
Rationale: The are various ways of starting an interpreter on different
*nix-like systems. Many use the simple
#!/usr/bin/perl
but it could be instead
#!/usr/local/bin/perl
and there is even the possibility that the user wants
#!/usr/bin/env perl
to find whichever perl comes first in the current $PATH. This is preferred
by some of us because we run multiple perl installations on the same box.
Adjusting our $PATH then allows us to set precedence over other perls, even
whatever the "house" version is.
Users on very non-unix systems like MS Windows do not have a kernel that does this kind of thing from the first line of script files, but instead the perl on their machine is started and merely notices whatever comes after the interpreter path on this first line of the script (options like "-w").
Acknowledgement: this macro was inspired in part by <ac_prog_perl_version> authored by Dean Povey, see the AC-Archive (ac-archive.sf.net).
AC_DEFUN([AX_SYS_PERLSHARPBANG],[dnl
AC_PATH_PROG(PERLINTERP,perl,perl)
ac_cv_path_perlinterp="$PERLINTERP"
_sHpB='#!'
AC_ARG_WITH(perl-shebang,
AC_HELP_STRING([--with-perl-shebang],
[override what perl thinks is the way for the kernel to start it (seldom needed)]dnl
),
[opt_perl_shebang="$withval"]dnl
,dnl
[opt_perl_shebang="not_set"]dnl
)dnl
AC_CACHE_CHECK([whether explicit instead of detected sharpbang is to be used],
ax_cv_opt_perl_shebang,
[ case "$opt_perl_shebang" in
not_set ) ax_cv_opt_perl_shebang=''
;;
* )
ax_cv_opt_perl_shebang=`echo "$opt_perl_shebang" | sed -e's|^#!\s*\(.*\)$|\1|'`
esac
]dnl
)dnl
if test "A$ax_cv_opt_perl_shebang" != "A"
then
ac_cv_sys_kernshrpbang_perl="$ax_cv_opt_perl_shebang"
PERL_SHEBANG="$ac_cv_sys_kernshrpbang_perl"
AC_SUBST(PERL_SHEBANG)dnl
AC_MSG_NOTICE([OK - PERL_SHEBANG is $_sHpB$PERL_SHEBANG.])
# Automatic detection of sharpbang formula starts here
else dnl
_somian_shbangperl=`$PERLINTERP -V:startperl`
negclass="[[^']]"; dnl
# must leave this comment: m4 will remove the outer brackets for us, heheh
AC_CACHE_CHECK([for kernel sharpbang invocation to start perl],
ac_cv_sys_kernshrpbang_perl,
[_somian_kspb_perl=`echo "$_somian_shbangperl" | sed -ne"s|.*='\($negclass*\)';$|\1|p"`
if test "x$_somian_kspb_perl" == x
then _somian_ksbp_warn_empty='durnit'
else
case "A$_somian_kspb_perl" in
A#!*perl* )
ac_cv_sys_kernshrpbang_perl=`echo "$_somian_kspb_perl" | sed -e's|#!\(.*\)$|\1|'`
;;
A* ) _somian_ksbp_warn_defau='trouble'
ac_cv_sys_kernshrpbang_perl="$PERLINTERP"
esac
fi
])dnl Done with testing sharpbang
# The above prints Checking ... result message to user.
PERL_SHEBANG="$ac_cv_sys_kernshrpbang_perl"
AC_SUBST(PERL_SHEBANG)
if test A${_somian_ksbp_warn_empty+set} == Aset
then AC_MSG_WARN([dnl
In last check, doing $PERLINTERP -V:startperl yielded empty result! That should not happen.])
fi
# Inform user after printing result value
if test A${_somian_ksbp_warn_defau+set} == Aset
then AC_MSG_NOTICE([Maybe Not good -])
AC_MSG_WARN([dnl
In last check perl's Config query did not work so we bunted: $_sHpB$PERLINTERP])
else AC_MSG_NOTICE([OK Good result - ])
AC_MSG_NOTICE([dnl
In last check we got a proper-looking answer from perl's Config: $_somian_shbangperl])
dnl Done with user info messages
fi
dnl Outer loop checked for user override term here
fi dnl
])dnl EOMACRO DEF