Well, it seems its as simple as:

use POSIX 'isdigit';
if (isdigit($c)) { print "$c is a digit" }
[download]

However, I don't think you really need to use this function. A regex might be faster: $c =~ /\A\d\z/ for example. Or, if you know you're dealing with ASCII: length($c) == 1 and ord($c) >= ord(0) and ord($c) <= ord(9) -- it's really up to you, though.

_____________________________________________________
Jeff[japhy]Pinyan: Perl, regex, and perl hacker, who'd like a job (NYC-area)
s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;