1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
<title>
Autoconf Macro: ax_sys_perlsharpbang
</title>
<link rel="stylesheet" type="text/css" href="ac-archive.css">
</head>
<body>
<table summary="web navigation" style="width:100%;">
<tbody>
<tr>
<td style="width:50%;" align="center">
<a href=
"http://autoconf-archive.cryp.to/ax_sys_perlsharpbang.m4">Download M4
Source</a>
</td>
<td style="width:50%;" align="center">
<a href="macros-by-category.html">Macro Index Page</a>
</td>
</tr>
</tbody>
</table>
<hr>
<h1>
ax_sys_perlsharpbang
</h1>
<h2>
Synopsis
</h2>
<p class="indent" style="white-space:nowrap;">
<code>AX_SYS_PERLSHARPBANG</code>
</p>
<h2>
Description
</h2>
<div class="indent">
<p>
Determine how the perl interpreter is located by the OS kernel and make
substitution variable PERL_SHEBANG available. Does AC_PATH_PROG to find the
path to perl. As a side-effect, that sets PERLINTERP and makes it available
as a substitution variable.
</p>
<p>
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:
</p>
<pre>
--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
</pre>
<p>
Rationale: The are various ways of starting an interpreter on different
*nix-like systems. Many use the simple
</p>
<pre>
#!/usr/bin/perl
</pre>
<p>
but it could be instead
</p>
<pre>
#!/usr/local/bin/perl
</pre>
<p>
and there is even the possibility that the user wants
</p>
<pre>
#!/usr/bin/env perl
</pre>
<p>
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 $PATH then allows us to set precedence over other perls, even
whatever the "house" version is.
</p>
<p>
Users on very non-unix systems like MS Windows do not have a kernel that
does this kind of thing from the first line of script files, but instead
the perl on their machine is started and merely notices whatever comes
after the interpreter path on this first line of the script (options like
"-w").
</p>
<p>
Acknowledgement: this macro was inspired in part by
<ac_prog_perl_version> authored by Dean Povey, see the AC-Archive
(ac-archive.sf.net).
</p>
</div>
<h2>
Author
</h2>
<p class="indent">
Soren Andersen <somian *AT* pobox |DOT| com>
</p>
<h2>
Last Modified
</h2>
<p class="indent">
2004-02-21
</p>
<h2>
M4 Source Code
</h2>
<div class="indent">
<pre class="m4source">
AC_DEFUN([AX_SYS_PERLSHARPBANG],[dnl
AC_PATH_PROG(PERLINTERP,perl,perl)
ac_cv_path_perlinterp="$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
</pre>
</div>
</body>
</html>
|
