my $sanity;
while(1){ 
  if(-e $pdffile){ last; } 
  sleep 1; 
  $sanity++; 
  if($sanity > 60){ return(0); }
  }

##</code><code>##

while(1){
select(undef, undef, undef, 0.5); # .5 second wait
my $usizer = (stat($pdffile))[7]; # how big is that file?
if($usizer eq $sizer){ last; } # did it grow at all?
$sizer = $usizer; # set size for next round
}