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387 <h1>sigchain API
</h1>
390 <div class=
"sectionbody">
391 <div class=
"paragraph"><p>Code often wants to set a signal handler to clean up temporary files or
392 other work-in-progress when we die unexpectedly. For multiple pieces of
393 code to do this without conflicting, each piece of code must remember
394 the old value of the handler and restore it either when:
</p></div>
395 <div class=
"olist arabic"><ol class=
"arabic">
398 The work-in-progress is finished, and the handler is no longer
399 necessary. The handler should revert to the original behavior
400 (either another handler, SIG_DFL, or SIG_IGN).
405 The signal is received. We should then do our cleanup, then chain
406 to the next handler (or die if it is SIG_DFL).
410 <div class=
"paragraph"><p>Sigchain is a tiny library for keeping a stack of handlers. Your handler
411 and installation code should look something like:
</p></div>
412 <div class=
"listingblock">
413 <div class=
"content">
414 <pre><tt> void clean_foo_on_signal(int sig)
423 sigchain_push_common(clean_foo_on_signal);
428 <div class=
"paragraph"><p>Handlers are given the typedef of sigchain_fun. This is the same type
429 that is given to signal() or sigaction(). It is perfectly reasonable to
430 push SIG_DFL or SIG_IGN onto the stack.
</p></div>
431 <div class=
"paragraph"><p>You can sigchain_push and sigchain_pop individual signals. For
432 convenience, sigchain_push_common will push the handler onto the stack
433 for many common signals.
</p></div>
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"footer-text">
438 Last updated
2011-
01-
04 22:
05:
44 UTC