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| 3 | magnus | 1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> |
| 2 | <html><head> |
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| 3 | <title>liboop: on_signal(), cancel_signal()</title> |
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| 4 | <link rel="stylesheet" type="text/css" href="style.css"> |
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| 5 | </head><body> |
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| 6 | |||
| 7 | <h2>on_signal(), cancel_signal()</h2> |
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| 8 | |||
| 9 | <pre> |
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| 10 | #include <oop.h> |
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| 11 | #include <signal.h> |
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| 12 | |||
| 13 | /* <em>Callback function prototype.</em> */ |
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| 14 | typedef void *oop_call_signal(oop_source *source,int sig,void *user); |
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| 15 | |||
| 16 | /* <em>Register and unregister UNIX signal event sinks.</em> */ |
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| 17 | void (*on_signal)(oop_source *source,int sig,oop_call_signal *call,void *user); |
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| 18 | void (*cancel_signal)(oop_source *source,int sig,oop_call_signal *call,void *user); |
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| 19 | </pre> |
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| 20 | |||
| 21 | <h3>Arguments.</h3> |
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| 22 | |||
| 23 | <dl> |
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| 24 | <dt><b>oop_source *source</b> |
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| 25 | <dd>The event source to register or unregister the event sink with. This must |
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| 26 | be the same event source you got the function pointer from: |
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| 27 | "src->on_signal(src,...);".<p> |
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| 28 | |||
| 29 | <dt><b>int sig</b> |
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| 30 | <dd>The UNIX signal to monitor (SIGINT, SIGHUP, etc.).<p> |
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| 31 | |||
| 32 | <dt><b>oop_call_signal *call</b> |
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| 33 | <dd>The callback function (event sink) to add (or remove).<p> |
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| 34 | |||
| 35 | <dt><b>void *user</b> |
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| 36 | <dd>User data passed through to the callback function.<p> |
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| 37 | </dl> |
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| 38 | |||
| 39 | <h3>Description.</h3> |
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| 40 | |||
| 41 | Note that these are not global functions, but function pointers supplied |
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| 42 | by the event source (in the <em>oop_source</em> structure) or by the user. |
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| 43 | |||
| 44 | <dl> |
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| 45 | <dt><b>on_signal</b> |
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| 46 | <dd>After this function is called, if the signal <em>sig</em> is received, |
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| 47 | when the event loop next runs (immediately, if it is currently waiting for |
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| 48 | events), the event source will call the function <em>call</em>, passing it a |
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| 49 | pointer to the event source, the signal received, and the same opaque |
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| 50 | <em>user</em> pointer passed to on_signal. This callback will be called |
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| 51 | again if the signal occurs again, but if the signal is received multiple times |
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| 52 | in quick succession the event sink may only receive a single callback. |
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| 53 | Many callbacks may be registered for the same signal.<p> |
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| 54 | |||
| 55 | <dt><b>cancel_signal</b> |
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| 56 | <dd>Deactivate an event sink callback registered using on_signal (above). If |
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| 57 | the passed <em>sig</em>, <em>call</em> and <em>user</em> match a previously |
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| 58 | registered callback, it will be removed; if they match more than one, one of |
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| 59 | them will be removed; otherwise, no action is taken.<p> |
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| 60 | |||
| 61 | <dt><b>oop_call_fd</b> |
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| 62 | <dd>Called when the event is triggered. Performs a user_specific action. |
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| 63 | Should return OOP_CONTINUE if the event loop should continue operating; any |
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| 64 | other value (including OOP_HALT) will cause termination of the event loop. |
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| 65 | </dl> |
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| 66 | |||
| 67 | <hr><a href="ref">liboop reference</a></body></html> |