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Full Discussion: signal handler problems
Top Forums Programming signal handler problems Post 302133815 by matrixmadhan on Sunday 26th of August 2007 08:14:50 AM
Old 08-26-2007
Adding to Perderabo's comment on using newer semantics of signal handling instead of older semantics.

Using signal function, while executing the code block within the signal handler there is no guarantee that another signal of the same type delivered would be handled the same way; instead the second signal of the same type delivered would default to its default action which in most of the cases would be to terminate.

for example:

Code:
signal code block {
/*  code instruction is currently here */  <== this instruction point
}

when its at the " this instruction point " and if a signal is again delivered at this point, proper house keeping operations intended for the signal handler will not be completed.

But this never happens with the newer semantics with sigaction,
when the code instructions are executed within the signal action block kernel guarantees that it will not deliver the same signal type until the signal action block is completed.

so with the newer semantics you are guaranteed that your house keeping operations are done.
 

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LEARN ABOUT HPUX

pthread_kill

pthread_kill(3T)														  pthread_kill(3T)

NAME

       pthread_kill() - send a signal to a thread

SYNOPSIS

PARAMETERS

	      thread	Thread to which the signal is to be delivered.

	      sig	Signal to be delivered to thread.

DESCRIPTION

       The  function  is  used	to  request  that a signal be delivered to thread.  The signal is asynchronously directed to thread in the calling
       process. The signal is handled in the context of the given thread; if the signal action results in the thread terminating or stopping, this
       action is applied to the whole process.

       If sig is zero, error checking is performed but a signal is not sent.

RETURN VALUE

       Upon successful completion, returns zero. Otherwise, an error number is returned to indicate the error (the variable is not set).

ERRORS

       If any of the following occur, the function returns the corresponding error number:

	      [EINVAL]	     sig is an invalid or unsupported signal number.

	      [ESRCH]	     No thread could be found corresponding to thread.

AUTHOR

       was derived from the IEEE POSIX P1003.1c standard.

SEE ALSO

       kill(2), sigaction(2), pthread_self(3T), raise(2).

STANDARDS CONFORMANCE

								  Pthread Library						  pthread_kill(3T)
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