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Re^2: Signals vs. Windows

by DanEllison (Beadle)
on Oct 03, 2012 at 17:33 UTC ( #997107=note: print w/replies, xml ) Need Help??


in reply to Re: Signals vs. Windows
in thread Signals vs. Windows

The pertinent text I missed was actually out of "threads" which was:

Correspondingly, sending a signal to a thread does not disrupt the operation the thread is currently working on: The signal will be acted upon after the current operation has completed. For instance, if the thread is stuck on an I/O call, sending it a signal will not cause the I/O call to be interrupted such that the signal is acted up immediately.

Nothing in the documentation suggests that signals are not the way to perform IPC, but simply threads don't react to signals as well as processes. Keep in mind, I don't want to simply suspend or terminate the thread, but interrupt it and send it off in another direction. So, the problem restated is, I guess, how do I interrupt a thread from an I/O operation?

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Re^3: Signals vs. Windows
by bulk88 (Priest) on Oct 03, 2012 at 19:48 UTC
    So, the problem restated is, I guess, how do I interrupt a thread from an I/O operation?

    1. dont use blocking I/O, use overlapped/async I/O

    2. use Native API, create an alertable *synchronous* file handle using NtCreateFile, post a timer APC to the blocked thread with SetWaitableTimer, the APC will call CancelIo from within the blocked thread, and the blocked I/O will unblock.
      I'm trying to avoid a Windows only solution.
Re^3: Signals vs. Windows
by Anonymous Monk on Oct 03, 2012 at 17:49 UTC

    Nothing in the documentation suggests that signals are not the way to perform IPC

    Hmm, "unsafe" about says it all :)

    So, the problem restated is, I guess, how do I interrupt a thread from an I/O operation?

    stop using safe signals, use unsafe signals, use kill

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