$a = tell(DATA);
seek(DATA,$a,0);

open(STDIN, "<&DATA");
while(<STDIN>){
  print "STDIN: $_";
}
__DATA__
Foo
Bar
Quux

##</code><code>##

while(<DATA>){
  print "DATA: $_";
}
seek(DATA,0,0);
open(STDIN, "<&DATA");
while(<STDIN>){
  print "STDIN: $_";
}
__DATA__
Foo
Bar
Quux