http://qs321.pair.com?node_id=212058
Description: Ask perl if a given scalar looks like a number (requires Inline::C).

Inspired by Slaven Rezic's "Include Perl_looks_like_number in Scalar::Util?" post to p5p.

Hopefully this function, or something very similar to it, should be making it into Scalar::Util per the p5p thread.

update: changed the title (was Is it a number?) as it was a little ambiguous in relation to the code

use Inline C;

my $var = shift;

print +(isnum($var) ? "is a number" : "not a number"), ": $var", $/;

__END__
__C__

int isnum(SV* val) {
  return Perl_looks_like_number(val);
}