Cross Platform Perl

[Paul Fenwick]

G'day Everyone,

	Rob and Adam are indeed correct.  You do need a string
eval and not a block eval.  My mistake.  :)

	Cheers,

		Paul

On Thu, Oct 17, 2002 at 01:27:37PM +1000, Rob Casey wrote:
> Just a follow up to this ...
> 
> > BEGIN {		# So we run at the same time as most use
> statements.
> > 	if ($^O eq 'MSWin32') {
> > 		eval { use My::Module; }
> > 	}
> > }
> 
> This will fail - As the compiler will find this use statement and
> attempt to include the module at this point.  To make use of dynamic
> loading of modules, the eval statement must called with a string
> argument as this string is not interpreted at compile time, but at the
> time of execution.
> 
> Regards,
> Rob
> 
> 
> Rob Casey
> Business Manager, Senior IT Consultant
> Cowsnet Internet and Professional Services
> http://www.cowsnet.com.au
> 
>  
> 
> -----Original Message-----
> From: owner-melbourne-pm at pm.org [mailto:owner-melbourne-pm at pm.org] On
> Behalf Of Paul Fenwick
> Sent: Thursday, 17 October 2002 1:02 PM
> To: Adam Clarke
> Cc: melbourne-pm at pm.org
> Subject: Re: Cross Platform Perl
> 
> 
> G'day Adam,
> 
> On Thu, Oct 17, 2002 at 12:42:42PM +1000, Adam Clarke wrote:
> 
> > I'm trying to write a script that runs on Linux (Unix) and Win32. I
> want 
> > to /use/ a module when on Win32 (to access the registry) that doesn't 
> > exist in Unixy perl. Is there a way to skip a use statement at runtime
> 
> > based on platform or is the only/best way to make a full build 
> > (MakeMaker thing) and handle the differences there somehow. If the 
> > latter, anyone got some simple pointers.
> 
> Glad you asked!  Perl has a variable called $^O (or $OSNAME when
> using English) that gives you the name of the operating system
> you're running under.
> 
> So you can do the following:
> 
> BEGIN {		# So we run at the same time as most use statements.
> 	if ($^O eq 'MSWin32') {
> 		eval { use My::Module; }
> 	}
> }
> 
> The eval is needed because usually use statements get executed
> immediately, regardless of context.  The BEGIN means that your
> chunk of code is executed "at compile time".  If this isn't important,
> you can leave the BEGIN block out.
> 
> There's lots of code out there which does different things depending
> upon the OS.  Take a look at File::Copy's source code
> (perldoc -m File::Copy) to see a lot of this in action.
> 
> Cheers,
> 
> 	Paul
> 
> -- 
> Paul Fenwick <pjf at perltraining.com.au> | http://perltraining.com.au/
> Director of Training                   | Ph:  +61 3 9354 6001
> Perl Training Australia                | Fax: +61 3 9354 2681
> 



-- 
Paul Fenwick <pjf at perltraining.com.au> | http://perltraining.com.au/
Director of Training                   | Ph:  +61 3 9354 6001
Perl Training Australia                | Fax: +61 3 9354 2681