$ cat t.pl
use strict;
use warnings;

# Scalar context
my $row = <DATA>;
print $row;

# Array context
my ($a) = <DATA>;
print $a;

# Now there's nothing left!
my $c = <DATA>;
print $c;

__DATA__
Now is the time
for all good men
to come to the aid
of their party

$ perl t.pl
Now is the time
for all good men
Use of uninitialized value $c in print at t.pl line 14, <DATA> line 5.