From: Ross Johnson <rpj@ise.canberra.edu.au>
To: "'Pthreads-win32'" <pthreads-win32@sourceware.cygnus.com>
Subject: Re: asynchronous cancellation
Date: Tue, 16 Nov 1999 19:17:00 -0000 [thread overview]
Message-ID: <Pine.LNX.4.05.9911171352420.256-100000@swan.canberra.edu.au> (raw)
In-Reply-To: <382CCAEB.ABCCED24@nbnet.nb.ca>
John, Jason, all,
The following applies to the C++ version of things, but SEH versions
should hopefully be similar.
Following on from John's explanation of C++ stack unwinding etc, and
the fact that pthreads-win32 implements cancelation by throwing an
exception, and the fact that the C++ version of pthread_cleanup_pop
is implemented as a destructor (after John's original
implementation):
For deferred cancelation:
1) stack unwinding should occur properly IMO
2) cleanup handlers should be called.
For async cancelation:
1) Jason's method could be used with the following simple change to
AsyncCancelPoint to work with the current pthreads-win32
mechanism:
void cancelThread(HANDLE hThread)
{
::SuspendThread(hThread);
if (::WaitForSingleObject(hThread, 0) != WAIT_TIMEDOUT) {
// Ok, thread did not exit before we got to it.
CONTEXT context;
context.ContextFlags = CONTEXT_CONTROL;
::GetThreadContext(hThread, &context);
// _x86 only!!!
context.Eip = (DWORD)AsyncCancelPoint;
::SetThreadContext(hThread, &context);
::ResumeThread(hThread);
}
}
// declare AsyncCancelPoint:
void AsyncCancelPoint()
{
// This is all it needs to do to call cleanup handlers,
// call object destructors, and exit the thread.
throw Pthread_exception_cancel();
}
For cancelation in general:
1) the following macro should be included in pthread.h:
#define catch(E) \
catch(Pthread_exception_cancel) { \
throw(); \
} \
catch(E)
Is this getting closer to the ideal, or am I way off the track?
Ross
+----------------------+---+
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+--------------------------+
next prev parent reply other threads:[~1999-11-16 19:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-11-12 18:08 Jason Nye
1999-11-16 19:17 ` Ross Johnson [this message]
1999-11-17 4:46 ` Jason Nye
1999-11-15 7:45 Bossom, John
1999-11-16 1:30 ` Ross Johnson
1999-11-16 13:11 ` Jason Nye
1999-11-16 14:40 Bossom, John
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