On Thu, 2002-03-28 at 14:55, [EMAIL PROTECTED] wrote: > Hello, All: > > I've never been very good at scoping so it it's no surprise that this > confuses me: > > When declaring variables at the beginning of a script, what is the > difference between 'my' and 'use vars'? > > -- > Eric P. > Los Gatos, CA
The big difference is that 'use vars;' doesn't produce warnings when used with Getopt::Std <grin>. I think it boils down to the fact that use vars is compiler directive (pragma) that prevents specific warnings from being issued and my is a function that declares a local variable. Variables get declared when they are used by default in Perl (unlike some languages like C). This can be a good thing if you only need 10 lines of code and don't want to waste time typing; however, it is a very bad thing in larger programs (ie you meant to type @commands but typed @command instead and it simple gets created). This is why they added warnings to tell you about one use variables and various other warnings. But that was not enough; some programmers still had tons of errors, so they added 'use strict;' which forces you to do some things that just make sense for large projects. Also note that use vars has been superseded by the our command in later versions of perl (5.6 and up). <snip href="perldoc vars"> NOTE: The functionality provided by this pragma has been superseded by "our" declarations, available in Perl v5.6.0 or later. See the our entry in the perlfunc manpage. </snip> -- Today is Boomtime the 14th day of Discord in the YOLD 3168 This statement is false. Missile Address: 33:48:3.521N 84:23:34.786W -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
