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author | Ulrich Drepper <drepper@redhat.com> | 1998-03-11 12:42:25 +0000 |
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committer | Ulrich Drepper <drepper@redhat.com> | 1998-03-11 12:42:25 +0000 |
commit | 5afdca0087dad2994ad4fcdfe7f489f4dbcab7b3 (patch) | |
tree | c9c82db2ff92537b921361a02a284b0e18a594b8 /linuxthreads/man/pthread_cancel.man | |
parent | 3d76e7784700c20fc222920b2a22baba006daa15 (diff) | |
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LinuxThreads library.
1998-03-11 00:42 Wolfram Gloger <wmglo@dent.med.uni-muenchen.de>
* linuxthreads/manager.c: Enable resetting of the thread
scheduling policy to SCHED_OTHER when the parent thread
has a different one.
1998-02-01 13:51 Ulrich Drepper <drepper@cygnus.com>
* sysdeps/unix/sysv/linux/bits/posix_opt.h: Define
_POSIX_ASYNCHRONOUS_IO.
* sysdeps/pthread/pthread.h: Define bits for Unix98 variants of
mutexes.
* mutex.c: Implement new mutex types.
* internals.h: Include <signal.h>.
* libpthread.map: Add __erno_location and __h_errno_location.
* errno.c: Return pointer to variable actually in use. This might
not be the one in the thread structure.
* internals.h (struct _pthread_descr_struct): Add new fields p_errnop
and p_h_errnop.
* manager.c (__pthread_manager): Set p_errnop and p_h_errnop member
of manager thread structure.
(pthread_handle_create): Set p_errnop and p_h_errnop members for new
thread.
* pthread.c: Adapt initializer for thread structures.
(__pthread_initial_thread): Set p_errnop and p_h_errnop member.
(__pthread_reset_main_thread): Reset p_errnop and p_h_errnop of
current thread to global variables.
1998-01-31 17:27 Ulrich Drepper <drepper@cygnus.com>
* rwlock.c: New file.
* Makefile (libpthread-routines): Add rwlock.
* sysdeps/pthread/pthread.h: Define data structures and declare
functions.
* libpthread.map: Add new functions.
1997-12-18 13:50 Philip Blundell <pb@nexus.co.uk>
* sysdeps/arm/pt-machine.h: New file; add ARM support.
* sysdeps/arm/Implies: likewise.
* README: Document it.
1997-12-13 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
* signals.c: Remove unneeded initializer for sigwaited, saving a
1997-04-11 01:18 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
* semaphore.c (sem_init): Set sem_spinlock only if available.
1997-12-04 01:48 Ulrich Drepper <drepper@cygnus.com>
* mutex.c: Implement PTHREAD_MUTEX_CHECKERROR.
* sysdeps/pthread/pthread.h: Define PTHREAD_MUTEX_CHECKERROR.
* Makefile: Update from LinuxThreads 0.7.
* internals.h. Likewise.
* manager.c: Likewise.
* mutex.c: Likewise.
* pthread.c: Likewise.
* signals.c: Likewise.
* specific.c: Likewise.
* Examples/ex3.c: Likewise.
1997-11-20 18:13 Ulrich Drepper <drepper@cygnus.com>
* pthread.c (__pthread_reset_main_thread): Close pipe only if still
open.
1997-10-29 05:38 Ulrich Drepper <drepper@cygnus.com>
* wrapsyscall.c: Add socket functions which are also cancelation
points.
1997-10-19 21:40 Wolfram Gloger <wg@wolfram.dent.med.uni-muenchen.de>
* specific.c (__libc_internal_tsd_set, __libc_internal_tsd_get):
New functions for fast thread specific data within libc.
* internals.h: Add new array p_libc_specific to struct
_pthread_descr_struct.
* sysdeps/pthread/bits/libc-lock.h: Declare new functions.
1997-10-13 05:39 Ulrich Drepper <drepper@cygnus.com>
* semaphore.h: Add __BEGIN_DECLS/__END_DECLS.
Reported by Ralf Corsepius <corsepiu@faw.uni-ulm.de>.
1997-08-29 03:05 Ulrich Drepper <drepper@cygnus.com>
* internals.h (struct _pthread_descr_struct): Add definitions for
two-level specific key handling.
* manager.c (pthread_handle_create): Initialize specific memory array.
* specific.c: Implement two-level key handling.
* weaks.c: Don't provide dummy key handling.
* sysdeps/pthread/bits/libc-lock.h: Typedef __libc_lock_t (no #define).
Add definition of __libc_key_t.
* sysdeps/unix/sysv/linux/bits/local_lim.h: Define PTHREAD_KEYS_MAX
as 1024.
Add definition of _POSIX_THREAD_DESTRUCTOR_ITERATIONS and
PTHREAD_DESTRUCTOR_ITERATIONS.
* manager.c (pthread_handle_create): Compare mmap result with
MAP_FAILED.
* ptfork.c: Rename to __pthread_atfork and make old name a weak alias.
* sysdeps/pthread/bits/pthread.h: Add prototype for __pthread_atfork.
1997-08-22 19:04 Richard Henderson <rth@cygnus.com>
sysdeps/sparc -> sysdeps/sparc/sparc32
sysdeps/sparc64 -> sysdeps/sparc/sparc64
* internals.h: Change definition of THREAD_SELF to be an expression,
not a statement that did a return.
* sysdeps/alpha/pt-machine.h (THREAD_SELF): Update accordingly.
* sysdeps/sparc/sparc32/pt-machine.h (THREAD_SELF, INIT_THREAD_SELF):
Follow Solaris and use a "system reserved" register (%g6) to hold
the thread descriptor.
* sysdeps/sparc/sparc64/pt-machine.h: Likewise.
1997-08-03 00:09 Ulrich Drepper <drepper@cygnus.com>
* mutex.c: Correct pthread_once. Patch by Xavier Leroy.
* sysdeps/pthread/pthread.h: Add prototype for __pthread_once.
* sysdeps/pthread/bits/pthread.h: Add macros for __libc_once.
* semaphore.c: Include spinlock.h only when needed.
* specific.c (__pthread_setsepcific, __pthread_getspecific): Reject
keys for entries not in use.
* weaks.c: Implement key handling functions for real.
1997-06-29 01:04 Richard Henderson <richard@gnu.ai.mit.edu>
Initial sparc64-linux support:
* linuxthreads/sysdeps/sparc64/Implies: New file.
* linuxthreads/sysdeps/sparc64/pt-machine.h: Likewise.
1997-06-29 00:48 Ulrich Drepper <drepper@cygnus.com>
* semaphore.c: Include spinlock.h at correct place.
Patch by HJ Lu.
1997-06-13 10:06 Richard Henderson <rth@tamu.edu>
The Great Bit File Move:
* sysdeps/alpha/semaphorebits.h: -> .../bits/semaphore.h.
* sysdeps/powerpc/semaphorebits.h: Likewise.
* sysdeps/pthread/cmpxchg/semaphorebits.h: Likewise.
* sysdeps/pthread/no-cmpxchg/semaphorebits.h: Likewise.
* sysdeps/pthread/libc-lock.h: -> bits/
* sysdeps/pthread/stdio-lock.h: Likewise.
* sysdeps/unix/sysv/linux/local_lim.h: Likewise.
* sysdeps/unix/sysv/linux/posix_opt.h: Likewise.
* semaphore.h: Likewise.
* sysdeps/pthread/pthread.h: Likewise.
* lockfile.c: <foo.h> -> <bits/foo.h>.
* semaphore.h: Likewise.
* Makefile: (headers): foo.h -> bits/foo.h.
* sysdeps/pthread/Makefile: Likewise.
1997-04-11 01:18 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
* semaphore.c (sem_init): Set sem_spinlock only if available.
* sysdeps/m68k/pt-machine.h (testandset, __compare_and_swap): Fix
asm constraints.
1997-04-09 03:00 Ulrich Drepper <drepper@cygnus.com>
Update from LinuxThreads 0.6.
* attr.c (pthread_attr_getdetachstate): Use __sched_get_priority_max
and __sched_get_priority_min instead of names without `__'.
* manager.c: Rewrite large parts to implement opaque pthread_t.
* cancel.c: Adapt for opaque pthread_t type.
* condvar.c: Likewise.
* errno.c: Likewise.
* join.c: Likewise.
* mutex.c: Likewise.
* pthread.c: Likewise.
* signals.c: Likewise.
* specific.c: Likewise.
* restart.h: Likewise.
* queue.h: Likewise.
* Examples/ex3.c: Likewise.
* Examples/ex4.c: Likewise.
* sysdeps/pthread/pthread.h: Likewise.
* pthread.c: Accumulate time for all threads in thread manager.
* semaphore.c: Implement fallback implementation for architectures
sometimes missing compare-exchange operations.
* cancel.c (pthread_cancel): Validate handle argument.
* join.c (pthread_join): Likewise.
(pthread_detach): Likewise.
* signals.c (pthread_kill): Likewise.
* spinlock.h (acquire): Use __sched_yield not sched_yield.
* queue.h (enqueue): Enqueue thread according to priority.
* internals.c (struct pthread_start_args): New struct for passing
args to cloning function.
(struct _pthread): Rename to _pthread_descr_struct and adapt for
opaque pthread_t.
* Examples/Makefile (clean): Pass -f option to rm.
* sysdeps/i386/pt-machine.h: Add check for compare-exchange instruction
and define TEST_FOR_COMPARE_AND_SWAP.
* sysdeps/i386/i486/pt-machine.h: Removed.
* sysdeps/unix/sysv/linux/local_lim.h (PTHREAD_THREADS_MAX): Increase
to 1024.
1997-04-04 16:38 Ulrich Drepper <drepper@cygnus.com>
* restart.h (suspend): Clear p_signal before suspending.
(suspend_with_cancellation): Likewise.
Patch by Xavier Leroy <Xavier.Leroy@inria.fr>.
* weaks.c: Make __pthread_key_create return 1.
* sysdeps/pthread/libc-lock.h: Define __libc_key_create,
__libc_getspecific, __libc_setspecific, and __libc_key_t.
* sysdeps/pthread/stdio-lock.h: Don't care for implementation not
using libio.
1997-03-19 15:13 Miguel de Icaza <miguel@nuclecu.unam.mx>
* sysdeps/sparc/pt-machine (RELEASE): Fix.
1997-03-01 07:55 Geoff Keating <geoffk@ozemail.com.au>
* sysdeps/powerpc/Implies: Added.
* sysdeps/powerpc/pt-machine.h: Added.
* sysdeps/powerpc/semaphorebits.h: Added.
1997-01-22 01:22 Ulrich Drepper <drepper@cygnus.com>
* linuxtheads/pthread.c (__pthread_initial_thread): Correct
initializer.
(__pthread_manager_thread): Likewise.
Reported by Andreas Jaeger.
1997-01-18 22:15 Richard Henderson <rth@tamu.edu>
Since sigset_t no longer fits in a register, we can't pass in the
thread's initial mask so easily. Take this opportunity to simplify
the clone implementation by only accepting a single void* argument.
* linuxthreads/manager.c (__pthread_manager): Put thread vitals
in the thread struct instead of as arguments through clone.
(pthread_start_thread): Look for them there.
* linuxthreads/internals.h (struct _pthread): Add p_initial_fn,
p_initial_fn_arg, p_initial_mask. Fix __pthread_manager proto.
* linuxthreads/pthread.c (pthread_initialize_manager): Revise
clone invocation.
Diffstat (limited to 'linuxthreads/man/pthread_cancel.man')
-rw-r--r-- | linuxthreads/man/pthread_cancel.man | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/linuxthreads/man/pthread_cancel.man b/linuxthreads/man/pthread_cancel.man new file mode 100644 index 0000000000..202d5c9b26 --- /dev/null +++ b/linuxthreads/man/pthread_cancel.man @@ -0,0 +1,155 @@ +.TH PTHREAD_CANCEL 3 LinuxThreads + +.XREF pthread_setcancelstate +.XREF pthread_setcanceltype +.XREF pthread_testcancel + +.SH NAME +pthread_cancel, pthread_setcancelstate, pthread_setcanceltype, pthread_testcancel \- thread cancellation + +.SH SYNOPSIS +#include <pthread.h> + +int pthread_cancel(pthread_t thread); + +int pthread_setcancelstate(int state, int *oldstate); + +int pthread_setcanceltype(int type, int *oldtype); + +void pthread_testcancel(void); + +.SH DESCRIPTION + +Cancellation is the mechanism by which a thread can terminate the +execution of another thread. More precisely, a thread can send a +cancellation request to another thread. Depending on its settings, the +target thread can then either ignore the request, honor it +immediately, or defer it till it reaches a cancellation point. + +When a thread eventually honors a cancellation request, it performs as +if !pthread_exit(PTHREAD_CANCELED)! has been called at that point: +all cleanup handlers are executed in reverse order, finalization +functions for thread-specific data are called, and finally the thread +stops executing with the return value !PTHREAD_CANCELED!. See +!pthread_exit!(3) for more information. + +!pthread_cancel! sends a cancellation request to the thread denoted +by the |thread| argument. + +!pthread_setcancelstate! changes the cancellation state for the +calling thread -- that is, whether cancellation requests are ignored +or not. The |state| argument is the new cancellation state: either +!PTHREAD_CANCEL_ENABLE! to enable cancellation, or +!PTHREAD_CANCEL_DISABLE! to disable cancellation (cancellation +requests are ignored). If |oldstate| is not !NULL!, the previous +cancellation state is stored in the location pointed to by |oldstate|, +and can thus be restored later by another call to +!pthread_setcancelstate!. + +!pthread_setcanceltype! changes the type of responses to cancellation +requests for the calling thread: asynchronous (immediate) or deferred. +The |type| argument is the new cancellation type: either +!PTHREAD_CANCEL_ASYNCHRONOUS! to cancel the calling thread as soon as +the cancellation request is received, or !PTHREAD_CANCEL_DEFERRED! to +keep the cancellation request pending until the next cancellation +point. If |oldtype| is not !NULL!, the previous +cancellation state is stored in the location pointed to by |oldtype|, +and can thus be restored later by another call to +!pthread_setcanceltype!. + +Threads are always created by !pthread_create!(3) with cancellation +enabled and deferred. That is, the initial cancellation state is +!PTHREAD_CANCEL_ENABLE! and the initial type is +!PTHREAD_CANCEL_DEFERRED!. + +Cancellation points are those points in the program execution where a +test for pending cancellation requests is performed and cancellation +is executed if positive. The following POSIX threads functions +are cancellation points: + +!pthread_join!(3) +.br +!pthread_cond_wait!(3) +.br +!pthread_cond_timedwait!(3) +.br +!pthread_testcancel!(3) +.br +!sem_wait!(3) +.br +!sigwait!(3) + +All other POSIX threads functions are guaranteed not to be +cancellation points. That is, they never perform cancellation in +deferred cancellation mode. + +!pthread_testcancel! does nothing except testing for pending +cancellation and executing it. Its purpose is to introduce explicit +checks for cancellation in long sequences of code that do not call +cancellation point functions otherwise. + +.SH "RETURN VALUE" + +!pthread_cancel!, !pthread_setcancelstate! and +!pthread_setcanceltype! return 0 on success and a non-zero error code +on error. + +.SH ERRORS +!pthread_cancel! returns the following error code on error: +.RS +.TP +!ESRCH! +no thread could be found corresponding to that specified by the |thread| ID. +.RE + +!pthread_setcancelstate! returns the following error code on error: +.RS +.TP +!EINVAL! +the |state| argument is not !PTHREAD_CANCEL_ENABLE! nor +!PTHREAD_CANCEL_DISABLE! +.RE + +!pthread_setcanceltype! returns the following error code on error: +.RS +.TP +!EINVAL! +the |type| argument is not !PTHREAD_CANCEL_DEFERRED! nor +!PTHREAD_CANCEL_ASYNCHRONOUS! +.RE + +.SH AUTHOR +Xavier Leroy <Xavier.Leroy@inria.fr> + +.SH "SEE ALSO" +!pthread_exit!(3), +!pthread_cleanup_push!(3), +!pthread_cleanup_pop!(3). + +.SH BUGS + +POSIX specifies that a number of system calls (basically, all +system calls that may block, such as !read!(2), !write!(2), !wait!(2), +etc.) and library functions that may call these system calls (e.g. +!fprintf!(3)) are cancellation points. LinuxThreads is not yet +integrated enough with the C library to implement this, and thus none +of the C library functions is a cancellation point. + +For system calls at least, there is a workaround. Cancellation +requests are transmitted to the target thread by sending it a +signal. That signal will interrupt all blocking system calls, causing +them to return immediately with the !EINTR! error. So, checking for +cancellation during a !read! system call, for instance, can be +achieved as follows: + +.RS +.ft 3 +.nf +.sp +pthread_testcancel(); +retcode = read(fd, buffer, length); +pthread_testcancel(); +.ft +.LP +.RE +.fi |