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/*
* cancel.c
*
* Description:
* POSIX thread functions related to thread cancellation.
*/
#include "pthread.h"
#include "implement.h"
/*
* Code contributed by John E. Bossom <JEB>.
*/
int
pthread_setcancelstate (int state, int *oldstate)
/*
* ------------------------------------------------------
* DOCPUBLIC
* This function atomically sets the calling thread's
* cancelability state to 'state' and returns the previous
* cancelability state at the location referenced by
* 'oldstate'
*
* PARAMETERS
* type,
* oldtype
* PTHREAD_CANCEL_ENABLE
* cancellation is enabled,
*
* PTHREAD_CANCEL_DISABLE
* cancellation is disabled
*
*
* DESCRIPTION
* This function atomically sets the calling thread's
* cancelability state to 'state' and returns the previous
* cancelability state at the location referenced by
* 'oldstate'
*
* NOTES:
* 1) Use to disable cancellation around 'atomic' code that
* includes cancellation points
*
* RESULTS
* 0 successfully set cancelability type,
* EINVAL 'state' is invalid
*
* ------------------------------------------------------
*/
{
pthread_t self;
int result;
if (((self = pthread_self ()) != NULL) &&
(state == PTHREAD_CANCEL_ENABLE ||
state == PTHREAD_CANCEL_DISABLE))
{
*oldstate = self->cancelState;
self->cancelState = state;
result = 0;
}
else
{
result = EINVAL;
}
return (result);
} /* pthread_setcancelstate */
int
pthread_setcanceltype (int type, int *oldtype)
/*
* ------------------------------------------------------
* DOCPUBLIC
* This function atomically sets the calling thread's
* cancelability type to 'type' and returns the previous
* cancelability type at the location referenced by
* 'oldtype'
*
* PARAMETERS
* type,
* oldtype
* PTHREAD_CANCEL_DEFERRED
* only deferred cancelation is allowed,
*
* PTHRAD_CANCEL_ASYNCHRONOUS
* Asynchronous cancellation is allowed
*
*
* DESCRIPTION
* This function atomically sets the calling thread's
* cancelability type to 'type' and returns the previous
* cancelability type at the location referenced by
* 'oldtype'
*
* NOTES:
* 1) Use with caution; most code is not safe for use
* with asynchronous cancelability.
*
* RESULTS
* 0 successfully set cancelability type,
* EINVAL 'type' is invalid
*
* ------------------------------------------------------
*/
{
pthread_t self;
int result;
if (((self = pthread_self ()) != NULL) &&
(type == PTHREAD_CANCEL_DEFERRED ||
type == PTHREAD_CANCEL_ASYNCHRONOUS))
{
*oldtype = self->cancelType;
self->cancelType = type;
result = 0;
}
else
{
result = EINVAL;
}
return (result);
} /* pthread_setcanceltype */
void
pthread_testcancel (void)
/*
* ------------------------------------------------------
* DOCPUBLIC
* This function creates a deferred cancellation point
* in the calling thread. The call has no effect if the
* current cancelability state is
* PTHREAD_CANCEL_DISABLE
*
* PARAMETERS
* N/A
*
*
* DESCRIPTION
* This function creates a deferred cancellation point
* in the calling thread. The call has no effect if the
* current cancelability state is
* PTHREAD_CANCEL_DISABLE
*
* NOTES:
* 1) Cancellation is asynchronous. Use pthread_join
* to wait for termination of thread if necessary
*
* RESULTS
* N/A
*
* ------------------------------------------------------
*/
{
pthread_t self;
if ((self = pthread_getspecific (_pthread_selfThreadKey)) != NULL)
{
if (self->cancelState == PTHREAD_CANCEL_ENABLE)
{
if (WaitForSingleObject (self->cancelEvent, 0) ==
WAIT_OBJECT_0)
{
/*
* Canceling!
*/
DWORD exceptionInformation[3];
exceptionInformation[0] = (DWORD) (0);
exceptionInformation[1] = (DWORD) (0);
RaiseException (
EXCEPTION_PTHREAD_SERVICES,
0,
3,
exceptionInformation);
}
}
}
} /* pthread_testcancel */
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 created semaphore,
* ESRCH no thread found corresponding to 'thread',
*
* ------------------------------------------------------
*/
{
int result;
if (thread != NULL)
{
if (!SetEvent (thread->cancelEvent))
{
result = ESRCH;
}
else
{
result = 0;
}
}
else
{
result = ESRCH;
}
return (result);
}
/* </JEB> */
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