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ax_sys_perlsharpbang

Synopsis

AX_SYS_PERLSHARPBANG

Description

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.

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 in part inspired by Dean Povey’s AC_PROG_PERL_VERSION.

Source Code

Download the latest version of ax_sys_perlsharpbang.m4 or browse the macro’s revision history.

License

Copyright © 2009 Soren Andersen somian@pobox.com

Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. This file is offered as-is, without any warranty.


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