IV_SIGNAL_INIT(3)

1iv_signal(3)              ivykis programmer's manual              iv_signal(3)
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NAME

6       IV_SIGNAL_INIT,  iv_signal_register, iv_signal_unregister - ivykis sig‐
7       nal handling
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SYNOPSIS

10       #include <iv_signal.h>
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12       struct iv_signal {
13               int             signum;
14               unsigned int    flags;
15               void            *cookie;
16               void            (*handler)(void *);
17       };
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19       void IV_SIGNAL_INIT(struct iv_signal *this);
20       int iv_signal_register(struct iv_signal *this);
21       void iv_signal_unregister(struct iv_signal *this);
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DESCRIPTION

24       iv_signal provides a way for ivykis(3)  applications  to  handle  POSIX
25       signals, by integrating them with the ivykis event loop.
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27       An  ivykis  application desiring signal notification registers a struct
28       iv_signal object  by  calling  iv_signal_register,  after  having  ini‐
29       tialised  it  with IV_SIGNAL_INIT and subsequently having filled in the
30       ->signum, ->cookie and ->handler members.
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32       Once the signal indicated by ->signum is delivered to any thread in the
33       current process, the callback specified by ->handler is scheduled to be
34       called in the thread that the struct iv_signal  object  was  registered
35       in, with ->cookie as its sole argument.
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37       If  the  same signal arrives again while the callback function is still
38       running, the callback function is guaranteed to be called  again  after
39       it returns.
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41       It  is  permitted to register multiple struct iv_signal objects for the
42       same signal number.  If all such objects are  registered  with  IV_SIG‐
43       NAL_FLAG_EXCLUSIVE  in  ->flags unset, then all objects will have their
44       callback functions called upon arrival of the signal, in no  guaranteed
45       order.
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47       Invoking  callback functions stops at the first struct iv_signal object
48       with IV_SIGNAL_FLAG_EXCLUSIVE in ->flags set, so that  if  all  objects
49       have  IV_SIGNAL_FLAG_EXCLUSIVE  set, only one callback function will be
50       invoked.
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52       To deinitialize a struct iv_signal  object,  call  iv_signal_unregister
53       from  the  same  thread that iv_signal_register was called from on that
54       object.
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56       It is permitted to unregister a struct iv_signal object from any ivykis
57       callback  function in the thread it was registered in, including from a
58       callback function triggered by this object, and it is permitted to free
59       the  memory  corresponding to an unregistered object from its own call‐
60       back function.
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62       It is guaranteed that signals delivered to child  processes  that  were
63       created  by  fork(2)  but  that  have not yet called execve(2) will not
64       cause iv_signal callbacks to be invoked in the parent process.
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66       Internally, iv_signal is implemented using iv_event_raw(3).
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NAME

SYNOPSIS

DESCRIPTION

SEE ALSO