use File::Temp qw( tempfile );

if ( 0 ) {
    print STDERR "required\n";
#    require FileHandle;
}

my ($fh, $file) = tempfile( UNLINK => 1 );

$fh->getline;

##</code><code>##

$ perl ttrap.t

##</code><code>##

$ perl ttrap.t
Can't locate object method "getline" via package "FileHandle" at ttrap.t line 12.

##</code><code>##

$ perl ttrap.t
required

##</code><code>##

require FileHandle;

##</code><code>##

eval 'require FileHandle';

##</code><code>##

use if $^V ge v5.10.0 && $^V lt v5.11.0, 'FileHandle';