What's this error in regex?

[Practical Perl]

Hello,

I got a warning message from my perl script,it's this:

Quantifier follows nothing in regex; marked by <-- HERE in m/? <-- HERE
?????/ at ./xxxx.pl line 703.

The 703st line is in a subroutine,the subroutine is:


sub some_sub
{
   my $arg1=shift;
   my $ok=0;

   for (@some_global_array)
   {
       return ($ok =1) if $arg1=~/$_/;
   }

   return $ok;
}



What this mean?thank you.