NAME

Perl::Exe - Find the perl executable that is currently running

SYNOPSIS

  # Locate the current perl
  my $perl = Perl::Exe::find;
  
  # Execute something in a child perl
  Perl::Exe::run3( [ '-e', 'print "Hello World!\n";' ] );

DESCRIPTION

Although Perl provides the $^X variable, which describes the currently running application, it is not a reliable cross-platform method to use if you wish to execute some delegate the execution of code to a child instance of the same Perl interpreter currently running.

That requires a bit more work, and in a few case some quite esoteric tricks.

The new Perl module build system Module::Build has some quite sophisticated code for locating the current Perl.

Unfortunately, it is not accesible directly (outside of installing a module) and it requires you to install an entire build system (with all the requisite time, load overhead and risk of failed tests) to answer a relatively simple question.

Perl::Exe is a port of the Module::Build find_perl_interpreter method into a standalone form. It has also been refactored to simplify the code slightly, remove the special cases needed when building inside the Perl core, and uses IPC::Run3 instead of the magic platform-sensing backtick/forking logic in Module::Build.

The result is a light-weight module with a very simple API that makes it easy to locate, or run something with, the current interpreter.

FUNCTIONS

For simply future maintenance and improve readability, Perl::Exe functions are not exportable into your own namespace.

However, to make up for this, the functions have been named in an exremely readable and straight-forward way (and the module name is short) so using the full function names should not be a burdon.

find

  my $perl = Perl::Exe::find;

The Perl::Exe::find function is the main way to locate the path of the current Perl interpreter.

It takes no parameters, and locates the Perl interpreter, caching the result and returning it as a simple string.

If the current Perl interpreter cannot be located, an exception is thrown.

discover

  my $perl = Perl::Exe::find;

The Perl::Exe::discover function is the direct method for location the current Perl interpreter, and contains the bulk of the logic.

You should only call Perl::Exe::discover directly if you intentionally want to avoid the cache and make a completely fresh attempt to determine the location of the Perl interpreter.

It takes no parameters, and locates the Perl interpreter, returning the path as a simple string and throwing an exception if the interpreter cannot be located.

The Perl::Exe::discover function is a direct port of the private method Module::Build::Base::_discover_perl_interpreter.

is

  if ( Perl::Exe::is($path) ) {
     print "The Perl interpreter is $path";
  }

The Perl::Exe::is function can be used to take a suspected path and determine if it is the path to the current Perl interpreter.

Returns true if the path is to the current Perl.

Returns false (but not undef) if there is no file at that path, of if the interpreter's confifiguration does not match that of the current Perl.

Because of the file test, any path to perl must contain the extention (such as .exe) if required on the current platform.

run3

  # Launch a CPAN shell for the current Perl
  Perl::Exe::run3( '-MCPAN -e shell' );
  
  # Capture some generated content
  my $stdout = '';
  Perl::Exe::run3(
      [ '-e', 'print "Hello World!\n";' ],
      undef,    # Inherit STDIN
      \$stdout, # Capture STDOUT
      \undef,   # Discard STDERR
  );

Because Perl::Exe uses IPC::Run3 internally for some functionality, a Perl::Exe::run3 pass-through function is provided as a convenience.

Except for the prepending of the path, this function is otherwise identical to IPC::Run3::run3.

It takes the same paremeters as IPC::Run3::run3 function, prepending the path to the current Perl (to either the string or ARRAY reference form of the command) and then hands off to the IPC::Run3::run3, returning the result.

SUPPORT

Bugs should be reported via the CPAN bug tracker at

http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Class-Adapter

For other issues, or commercial support, contact the author.

AUTHOR

Adam Kennedy <adamk@cpan.org>

SEE ALSO

Module::Build, IPC::Run3

COPYRIGHT

Copyright 2008 Adam Kennedy.

Some parts copyright Ken Williams 2001 - 2006.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

The full text of the license can be found in the LICENSE file included with this module.

cpanm Perl::Exe

perl -MCPAN -e shell
install Perl::Exe