--- tom poe <[EMAIL PROTECTED]> wrote:
> Hi, Zentara: I fiddled [far more than one would expect], and used the
> recently posted write to file format above, and it works with the top line,
> "#! /usr/bin/perl -w". But, if I add "use strict;" at the top of the script,
> I can't compile:
> tompoe@aether:~/perlStuff > createpng
> Global symbol "$im" requires explicit package name at ./createpng line 5.
> Global symbol "$red" requires explicit package name at ./createpng line 7.
> Global symbol "$im" requires explicit package name at ./createpng line 7.
> Global symbol "$blue" requires explicit package name at ./createpng line 8.
> Global symbol "$im" requires explicit package name at ./createpng line 8.
> Global symbol "$im" requires explicit package name at ./createpng line 11.
> Global symbol "$blue" requires explicit package name at ./createpng line 11.
> Global symbol "$im" requires explicit package name at ./createpng line 13.
> Global symbol "$red" requires explicit package name at ./createpng line 13.
> Global symbol "$im" requires explicit package name at ./createpng line 19.
> Execution of ./createpng aborted due to compilation errors.
>
> So, since we're here, do you understand what the message is? A required
> explicit package name? I'm lost. Thanks, Tom
Tom,
What that means is that the variables (global symbols) need to be declared prior to
their being
used. This is a Good Thing because this helps to alleviate typos in variable names.
The first
time you use one of those variables in a given scope, preface the use with 'my'. For
example:
my $im = new GD::Image(100,100);
In large applications, typing $recieved instead of $received is very annoying and
tough to spot.
Using 'strict' will prevent this. See 'perldoc strict' for more examples.
You can read http://www.perlmonks.org/index.pl?node_id=108286 for a more thorough
explanation of
this (and it includes other programming tips as well).
Cheers,
Curtis "Ovid" Poe
=====
Senior Programmer
Onsite! Technology (http://www.onsitetech.com/)
"Ovid" on http://www.perlmonks.org/
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