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Note that this is the status word returned by the wait() system call (or else is made up to look like it). Thus, the exit value of the subprocess is actually (<code>$? >> 8</code>), and <code>$? & 127</code> gives which signal, if any, the process died from, and <code>$? & 128</code> reports whether there was a core dump. (Mnemonic: similar to <b>sh</b> and <b>ksh</b>.)</p> <p>Additionally, if the <code>h_errno</code> variable is supported in C, its value is returned via $? if any of the <code>gethost*()</code> functions fail.</p> <p>Note that if you have installed a signal handler for <code>SIGCHLD</code>, the value of <code>$?</code> will usually be wrong outside that handler.</p> <p>Inside an <code>END</code> subroutine <code>$?</code> contains the value that is going to be given to <code>exit()</code>. You can modify <code>$?</code> in an <code>END</code> subroutine to change the exit status of the script.</p> <p>Under VMS, the pragma <code>use vmsish 'status'</code> makes <code>$?</code> reflect the actual VMS exit status, instead of the default emulation of POSIX status.</p> <p>Also see <a href="/5.005_01/perlvar#Error-Indicators">"Error Indicators"</a>.</p> </dd> </dl> </div> <div id="footer"> <p>Perldoc Browser is maintained by Dan Book (<a href="https://metacpan.org/author/DBOOK">DBOOK</a>). Please contact him via the <a href="https://github.com/Grinnz/perldoc-browser/issues">GitHub issue tracker</a> or <a href="mailto:dbook@cpan.org">email</a> regarding any issues with the site itself, search, or rendering of documentation.</p> <p>The Perl documentation is maintained by the Perl 5 Porters in the development of Perl. 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