Hi!
On 09:48 Tue 09 Sep , Wang Yu wrote:
> I have the following questions:
> 1. In line 58 when I call sigaction to associate a action
> handler(act.sa_handler or act.sa_sigaction)
> with a signal SIGUSR1, how can I pass a parameter(for
> example:pthread_id1) to the handler?
I do not think this is possible. Why do you want to do this? You can store
whatever you want to pass as a global variable.
> 2. In thread1 when it receives a signal SIGUSR1, it will call the handler
> reintegration. From the running
> result we can find that the thread id of thread1 is 1082132832 (from line
> 77) and the thread id of
> reintegration is 1082132832l (from line 80). Is there some relation
> between these two thread id ?
No, it is completly random and even if you find out this is not the case it
might be random in a future kernel version. See "man 2 clone" (thi syscall
behind pthread_create):
CLONE_THREAD (since Linux 2.4.0-test8)
...
Each thread has its own signal mask, as set by sigprocmask(2),
but signals can be pending either: for the whole process (i.e.,
deliverable to any member of the thread group), when sent with
kill(2); or for an individual thread, when sent with tgkill(2).
A call to sigpending(2) returns a signal set that is the union
of the signals pending for the whole process and the signals
that are pending for the calling thread.
If kill(2) is used to send a signal to a thread group, and the
thread group has installed a handler for the signal, then the
handler will be invoked in exactly one, arbitrarily selected
member of the thread group that has not blocked the signal. If
multiple threads in a group are waiting to accept the same sig-
nal using sigwaitinfo(2), the kernel will arbitrarily select one
of these threads to receive a signal sent using kill(2).
Be *very* careful not to create any race conditions!
-Michi
--
programing a layer 3+4 network protocol for mesh networks
see http://michaelblizek.twilightparadox.com
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