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Q&A

Q1:

In the File::Find module, what are the colons (::) in the variable names? Like $File::Find::dir?

A1:

Perl modules can create alternate areas for variable names, called namespaces, so that the module's global variable names and your global variable names don't get mixed up. So a global variable in the Cwd module would be known as $Cwd::x. Most of your global variables actually have the full name of $main::x for $x. But for now, that's not important.

Q2:

I have a Windows 95/98/NT machine, and the module I want to use is not available through ActiveState's PPM. How can I install it?

A2:

Unfortunately, most of CPAN's modules assume that you have a full Unix-like development environment to compile and install modules; this kind of environment is not easy to put together on a Windows machine. If you're very handy with a C compiler, you can download a development environment and build your own module, but doing so is not easy. Some modules are written entirely in Perl, and it may just be a matter of opening the distribution and putting the files in the correct places.

Q3:

I have an older Perl program with require instead of use. What's require?

A3:

The require statement is similar to use, and because Perl 4 did not have the use keyword, it used require. (Follow that?) The require statement causes the interpreter to find a library file and include it in your programsimilar to use. However, the key difference is that a require happens whenever the require statement is run (at runtime), whereas the use directive happens when your program is first loaded (at compile time).

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