multithreading - POSIX 取消点是什么？

Question

POSIX 取消点是什么？我正在寻找一份明确的 POSIX 取消点列表。

我问是因为我有一本书上写着 accept()和 select()是取消点，但我看到互联网上的网站声称它们不是。

此外，如果 Linux 取消点与 POSIX 取消点不同，我也想要一份它们的列表。

Answer 1

POSIX 1003.1-2003标准在系统接口(interface)部分给出了一个列表，然后是一般信息，然后是线程(direct link 由 A. Rex 提供)。
(已添加:POSIX 1003.1-2008 现已在网络上提供(全部 3872 页，PDF 和 HTML 格式)。您必须注册(免费)。我是从 Open Group Bookstore 获得的。)

取消积分

Cancellation points shall occur when a thread is executing the following functions:

• accept()
• aio_suspend()
• clock_nanosleep()
• close()
• connect()
• creat()
• fcntl() (When the cmd argument is F_SETLKW)
• fdatasync()
• fsync()
• getmsg()
• getpmsg()
• lockf()
• mq_receive()
• mq_send()
• mq_timedreceive()
• mq_timedsend()
• msgrcv()
• msgsnd()
• msync()
• nanosleep()
• open()
• pause()
• poll()
• pread()
• pselect()
• pthread_cond_timedwait()
• pthread_cond_wait()
• pthread_join()
• pthread_testcancel()
• putmsg()
• putpmsg()
• pwrite()
• read()
• readv()
• recv()
• recvfrom()
• recvmsg()
• select()
• sem_timedwait()
• sem_wait()
• send()
• sendmsg()
• sendto()
• sigpause()
• sigsuspend()
• sigtimedwait()
• sigwait()
• sigwaitinfo()
• sleep()
• system()
• tcdrain()
• usleep()
• wait()
• waidid()
• waitpid()
• write()
• writev()

A cancellation point may also occur when a thread is executing the following functions:

• access()
• asctime()
• asctime_r()
• catclose()
• catgets()
• catopen()
• closedir()
• closelog()
• ctermid()
• ctime()
• ctime_r()
• dbm_close()
• dbm_delete()
• dbm_fetch()
• dbm_nextkey()
• dbm_open()
• dbm_store()
• dlclose()
• dlopen()
• endgrent()
• endhostent()
• endnetent()
• endprotoent()
• endpwent()
• endservent()
• endutxent()
• fclose()
• fcntl() (For any value of the cmd argument. [Presumably except F_SETLKW which is listed.]
• fflush()
• fgetc()
• fgetpos()
• fgets()
• fgetwc()
• fgetws()
• fmtmsg()
• fopen()
• fpathconf()
• fprintf()
• fputc()
• fputs()
• fputwc()
• fputws()
• fread()
• freopen()
• fscanf()
• fseek()
• fseeko()
• fsetpos()
• fstat()
• ftell()
• ftello()
• ftw()
• fwprintf()
• fwrite()
• fwscanf()
• getaddrinfo()
• getc()
• getc_unlocked()
• getchar()
• getchar_unlocked()
• getcwd()
• getdate()
• getgrent()
• getgrgid()
• getgrgid_r()
• getgrnam()
• getgrnam_r()
• gethostbyaddr()
• gethostbyname()
• gethostent()
• gethostid()
• gethostname()
• getlogin()
• getlogin_r()
• getnameinfo()
• getnetbyaddr()
• getnetbyname()
• getnetent()
• getopt() (if opterr is non-zero.)
• getprotobyname()
• getprotobynumber()
• getprotoent()
• getpwent()
• getpwnam()
• getpwnam_r()
• getpwuid()
• getpwuid_r()
• gets()
• getservbyname()
• getservbyport()
• getservent()
• getutxent()
• getutxid()
• getutxline()
• getwc()
• getwchar()
• getwd()
• glob()
• iconv_close()
• iconv_open()
• ioctl()
• link()
• localtime()
• localtime_r()
• lseek()
• lstat()
• mkstemp()
• mktime()
• nftw()
• opendir()
• openlog()
• pathconf()
• pclose()
• perror()
• popen()
• posix_fadvise()
• posix_fallocate()
• posix_madvise()
• posix_openpt()
• posix_spawn()
• posix_spawnp()
• posix_trace_clear()
• posix_trace_close()
• posix_trace_create()
• posix_trace_create_withlog()
• posix_trace_eventtypelist_getne
• posix_trace_eventtypelist_rewin
• posix_trace_flush()
• posix_trace_get_attr()
• posix_trace_get_filter()
• posix_trace_get_status()
• posix_trace_getnext_event()
• posix_trace_open()
• posix_trace_rewind()
• posix_trace_set_filter()
• posix_trace_shutdown()
• posix_trace_timedgetnext_event(
• posix_typed_mem_open()
• printf()
• pthread_rwlock_rdlock()
• pthread_rwlock_timedrdlock()
• pthread_rwlock_timedwrlock()
• pthread_rwlock_wrlock()
• putc()
• putc_unlocked()
• putchar()
• putchar_unlocked()
• puts()
• pututxline()
• putwc()
• putwchar()
• readdir()
• readdir_r()
• remove()
• rename()
• rewind()
• rewinddir()
• scanf()
• seekdir()
• semop()
• setgrent()
• sethostent()
• setnetent()
• setprotoent()
• setpwent()
• setservent()
• setutxent()
• stat()
• strerror()
• strerror_r()
• strftime()
• symlink()
• sync()
• syslog()
• tmpfile()
• tmpnam()
• ttyname()
• ttyname_r()
• tzset()
• ungetc()
• ungetwc()
• unlink()
• vfprintf()
• vfwprintf()
• vprintf()
• vwprintf()
• wcsftime()
• wordexp()
• wprintf()
• wscanf()

An implementation shall not introduce cancellation points into any other functions specified in this volume of IEEE Std 1003.1-2001.

The side effects of acting upon a cancellation request while suspended during a call of a function are the same as the side effects that may be seen in a single-threaded program when a call to a function is interrupted by a signal and the given function returns [EINTR]. Any such side effects occur before any cancellation cleanup handlers are called.

Whenever a thread has cancelability enabled and a cancellation request has been made with that thread as the target, and the thread then calls any function that is a cancellation point (such as pthread_testcancel() or read()), the cancellation request shall be acted upon before the function returns. If a thread has cancelability enabled and a cancellation request is made with the thread as a target while the thread is suspended at a cancellation point, the thread shall be awakened and the cancellation request shall be acted upon. However, if the thread is suspended at a cancellation point and the event for which it is waiting occurs before the cancellation request is acted upon, it is unspecified whether the cancellation request is acted upon or whether the cancellation request remains pending and the thread resumes normal execution.

啊!不能让 table 很好地工作，它在预览中看起来不错，之后就不像 table 了。请查看网址以获取信息!
有很多可能的取消点。