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copied!<p>As explained in <a href="http://perldoc.perl.org/perlvar.html#%25SIG" rel="noreferrer">perlvar</a>, due to an implementation glitch <code>$SIG{__DIE__}</code> hooks get called even when code <a href="http://perldoc.perl.org/functions/die.html" rel="noreferrer">die</a>s inside an <a href="http://perldoc.perl.org/functions/eval.html" rel="noreferrer">eval</a>. When <a href="http://search.cpan.org/perldoc?File::stat" rel="noreferrer">File::stat</a> is loaded, it checks to see what constants <a href="http://search.cpan.org/perldoc?Fcntl" rel="noreferrer">Fcntl</a> supports on your platform. It catches the errors caused by unsupported constants, but not before your hook sees them.</p> <p>You can tell if you're in an <code>eval</code> by checking the value of <a href="http://perldoc.perl.org/perlvar.html#$EXCEPTIONS_BEING_CAUGHT" rel="noreferrer"><code>$^S</code></a>. If it's not 0, then you're in an eval.</p> <pre><code>$SIG{__DIE__} = sub { return unless defined $^S and $^S == 0; # Ignore errors in eval my ($error) = @_; chomp $error; print "die: $error\n"; }; </code></pre> <p>You don't see the errors when you <code>use</code> instead of <code>require</code> because <code>use</code> is a compile-time operation and <code>require</code> is a run-time operation (as is setting <code>%SIG</code>). When you <code>use mod</code> and it <code>use</code>s File::stat, that all happens <em>before</em> you set up your hook. When you <code>require mod</code>, that doesn't happen until <em>after</em> you've installed your hook.</p>

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