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diff --git a/pthreads/pthread_cancel.c b/pthreads/pthread_cancel.c
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+/*
+ * pthread_cancel.c
+ *
+ * Description:
+ * POSIX thread functions related to thread cancellation.
+ *
+ * --------------------------------------------------------------------------
+ *
+ * Pthreads-win32 - POSIX Threads Library for Win32
+ * Copyright(C) 1998 John E. Bossom
+ * Copyright(C) 1999,2005 Pthreads-win32 contributors
+ *
+ * Contact Email: rpj@callisto.canberra.edu.au
+ *
+ * The current list of contributors is contained
+ * in the file CONTRIBUTORS included with the source
+ * code distribution. The list can also be seen at the
+ * following World Wide Web location:
+ * http://sources.redhat.com/pthreads-win32/contributors.html
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library in the file COPYING.LIB;
+ * if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include "pthread.h"
+#include "implement.h"
+
+#if defined(_M_IX86) || defined(_X86_)
+#define PTW32_PROGCTR(Context) ((Context).Eip)
+#endif
+
+#if defined (_M_IA64)
+#define PTW32_PROGCTR(Context) ((Context).StIIP)
+#endif
+
+#if defined(_MIPS_)
+#define PTW32_PROGCTR(Context) ((Context).Fir)
+#endif
+
+#if defined(_ALPHA_)
+#define PTW32_PROGCTR(Context) ((Context).Fir)
+#endif
+
+#if defined(_PPC_)
+#define PTW32_PROGCTR(Context) ((Context).Iar)
+#endif
+
+#if defined(_AMD64_)
+#define PTW32_PROGCTR(Context) ((Context).Rip)
+#endif
+
+#if !defined(PTW32_PROGCTR)
+#error Module contains CPU-specific code; modify and recompile.
+#endif
+
+static void
+ptw32_cancel_self (void)
+{
+ ptw32_throw (PTW32_EPS_CANCEL);
+
+ /* Never reached */
+}
+
+static void CALLBACK
+ptw32_cancel_callback (DWORD unused)
+{
+ ptw32_throw (PTW32_EPS_CANCEL);
+
+ /* Never reached */
+}
+
+/*
+ * ptw32_RegisterCancelation() -
+ * Must have args of same type as QueueUserAPCEx because this function
+ * is a substitute for QueueUserAPCEx if it's not available.
+ */
+DWORD
+ptw32_RegisterCancelation (PAPCFUNC unused1, HANDLE threadH, DWORD unused2)
+{
+ CONTEXT context;
+
+ context.ContextFlags = CONTEXT_CONTROL;
+ GetThreadContext (threadH, &context);
+ PTW32_PROGCTR (context) = (DWORD_PTR) ptw32_cancel_self;
+ SetThreadContext (threadH, &context);
+ return 0;
+}
+
+int
+pthread_cancel (pthread_t thread)
+ /*
+ * ------------------------------------------------------
+ * DOCPUBLIC
+ * This function requests cancellation of 'thread'.
+ *
+ * PARAMETERS
+ * thread
+ * reference to an instance of pthread_t
+ *
+ *
+ * DESCRIPTION
+ * This function requests cancellation of 'thread'.
+ * NOTE: cancellation is asynchronous; use pthread_join to
+ * wait for termination of 'thread' if necessary.
+ *
+ * RESULTS
+ * 0 successfully requested cancellation,
+ * ESRCH no thread found corresponding to 'thread',
+ * ENOMEM implicit self thread create failed.
+ * ------------------------------------------------------
+ */
+{
+ int result;
+ int cancel_self;
+ pthread_t self;
+ ptw32_thread_t * tp;
+
+ result = pthread_kill (thread, 0);
+
+ if (0 != result)
+ {
+ return result;
+ }
+
+ if ((self = pthread_self ()).p == NULL)
+ {
+ return ENOMEM;
+ };
+
+ /*
+ * FIXME!!
+ *
+ * Can a thread cancel itself?
+ *
+ * The standard doesn't
+ * specify an error to be returned if the target
+ * thread is itself.
+ *
+ * If it may, then we need to ensure that a thread can't
+ * deadlock itself trying to cancel itself asyncronously
+ * (pthread_cancel is required to be an async-cancel
+ * safe function).
+ */
+ cancel_self = pthread_equal (thread, self);
+
+ tp = (ptw32_thread_t *) thread.p;
+
+ /*
+ * Lock for async-cancel safety.
+ */
+ (void) pthread_mutex_lock (&tp->cancelLock);
+
+ if (tp->cancelType == PTHREAD_CANCEL_ASYNCHRONOUS
+ && tp->cancelState == PTHREAD_CANCEL_ENABLE
+ && tp->state < PThreadStateCanceling)
+ {
+ if (cancel_self)
+ {
+ tp->state = PThreadStateCanceling;
+ tp->cancelState = PTHREAD_CANCEL_DISABLE;
+
+ (void) pthread_mutex_unlock (&tp->cancelLock);
+ ptw32_throw (PTW32_EPS_CANCEL);
+
+ /* Never reached */
+ }
+ else
+ {
+ HANDLE threadH = tp->threadH;
+
+ SuspendThread (threadH);
+
+ if (WaitForSingleObject (threadH, 0) == WAIT_TIMEOUT)
+ {
+ tp->state = PThreadStateCanceling;
+ tp->cancelState = PTHREAD_CANCEL_DISABLE;
+ /*
+ * If alertdrv and QueueUserAPCEx is available then the following
+ * will result in a call to QueueUserAPCEx with the args given, otherwise
+ * this will result in a call to ptw32_RegisterCancelation and only
+ * the threadH arg will be used.
+ */
+ ptw32_register_cancelation (ptw32_cancel_callback, threadH, 0);
+ (void) pthread_mutex_unlock (&tp->cancelLock);
+ ResumeThread (threadH);
+ }
+ }
+ }
+ else
+ {
+ /*
+ * Set for deferred cancellation.
+ */
+ if (tp->state < PThreadStateCancelPending)
+ {
+ tp->state = PThreadStateCancelPending;
+ if (!SetEvent (tp->cancelEvent))
+ {
+ result = ESRCH;
+ }
+ }
+ else if (tp->state >= PThreadStateCanceling)
+ {
+ result = ESRCH;
+ }
+
+ (void) pthread_mutex_unlock (&tp->cancelLock);
+ }
+
+ return (result);
+}