Simpler: 
my $sub_x = 'Some::Sub';
if (defined(&$sub_x)) {
    print("It's there\n");
} else {
    print("It's not there\n");
}

[download]

In reply to Re^2: Check for sub / don't fail on non-existent sub by ikegami
in thread Check for sub / don't fail on non-existent sub by Sewi

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