Longer but quite possibly faster if it matters....

#!/usr/bin/perl
use Inline 'C';
@ary = 1..10;
print multiply( \@ary );

__DATA__
__C__
double multiply (SV * terms)
{
    I32 numterms = 0;
    double res = 1.0;
    int i;
    if ((!SvROK(terms))
        || (SvTYPE(SvRV(terms)) != SVt_PVAV)
        || ((numterms = av_len((AV *)SvRV(terms))) < 0))
    {
      return 0;
    }
    for (i = 0; i <= numterms; i++) {
        res *= SvNV(* av_fetch((AV *)SvRV(terms), i, 0));
    }
  return res;
}
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