67 lines
2.7 KiB
HTML
67 lines
2.7 KiB
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<title>Groups of signals - SBCL Internals</title>
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<link rel="up" href="Signal-handling.html#Signal-handling" title="Signal handling">
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<link rel="next" href="The-deferral-mechanism.html#The-deferral-mechanism" title="The deferral mechanism">
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This manual is part of the SBCL software system. See the `README'
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file for more information.
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This manual is in the public domain and is provided with
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<p>
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<a name="Groups-of-signals"></a>
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Next: <a rel="next" accesskey="n" href="The-deferral-mechanism.html#The-deferral-mechanism">The deferral mechanism</a>,
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Up: <a rel="up" accesskey="u" href="Signal-handling.html#Signal-handling">Signal handling</a>
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<hr>
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</div>
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<h3 class="section">6.1 Groups of signals</h3>
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<p>There are two distinct groups of signals.
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<h4 class="subsection">6.1.1 Semi-synchronous signals</h4>
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<p>The first group, tentatively named “semi-synchronous”, consists of
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signals that are raised on illegal instruction, hitting a protected
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page, or on a trap. Examples from this group are:
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<code>SIGBUS</code>/<code>SIGSEGV</code>, <code>SIGTRAP</code>, <code>SIGILL</code> and
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<code>SIGEMT</code>. The exact meaning and function of these signals varies
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by platform and OS. Understandably, because these signals are raised
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in a controllable manner they are never blocked or deferred.
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<h4 class="subsection">6.1.2 Blockable signals</h4>
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<p>The other group is of blockable signals. Typically, signal handlers
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block them to protect against being interrupted at all. For example
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<code>SIGHUP</code>, <code>SIGINT</code>, <code>SIGQUIT</code> belong to this group.
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<p>With the exception of <code>SIG_STOP_FOR_GC</code> all blockable signals are
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deferrable.
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</body></html>
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