-----Original Message-----
From: Mr. Shawn H. Corey [mailto:[EMAIL PROTECTED]
Sent: Monday, May 01, 2006 7:36 PM
To: chen li
Cc: beginners@perl.org
Subject: Re: What is the function of BEGIN in perl
On Mon, 2006-01-05 at 15:32 -0700, chen li wrote:
> Dear all,
>
> Recently I read some source codes of perl modules. I
> find some codes look like this:
>
> BEGIN {..................}
>
> What is the function of BEGIN here?
>BEGIN clauses are executed immediately after they are compiled. As
such,
>they can be used to redirect the compilation of the remaining code. For
>example, if you write a module that is dependant on the operating
>system, that is, there is different code for different operating
>systems, you could use BEGIN to load the appropriate subroutines:
>#!/
>package MyModule;
>BEGIN {
> if( $^O eq 'MSDos' ){
> require 'MyModule::MSDos.pm';
> }elsif( $^O eq 'MacOSX' ){
> require 'MyModule::MacOSX.pm';
> }else{
> require 'MyModule::Generic.pm';
> }
>}
>If the normal course of affairs, you would not need it. But if you do
>need it, it is there. (In other words, don't worry about it unless all
>else fails).
************************************************************************
***
Doesn't the BEGIN and INIT constructs provide the same behavior?
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