It's a bug in select(), and is still present in blead. Looks like select() isn't calling get magic on the timeout arg.

Here's another example of using a magic var which fails unless its magic value has been previously retrieved (using the commented-out line):

"5" =~ /(\d)/;
#$x = $1;
select (undef, undef, undef, $1);
[download]

You may want to perlbug this.

Dave.