sigwait() cancellation point

David Xu davidxu at freebsd.org
Thu Sep 9 06:29:28 UTC 2010


Jilles Tjoelker wrote:
> On Tue, Sep 07, 2010 at 05:38:06PM +0000, David Xu wrote:
>> Jilles Tjoelker wrote:
>>> Our sigwait() implementation may not be POSIX-compliant as it returns
>>> EINTR when it is interrupted by a caught signal. (Unfortunately I can
>>> only find this in SUSv4 in the Rationale, B.2.3 Error Numbers,
>>> Disallowing Return of the [EINTR] Error Code; the sigwait() page in XSH
>>> does not list an [EINTR] error condition, but does not prohibit one
>>> either like pthread_mutex_lock() and various others do.)
> 
>> A system call can not return EINTR is not flexible, I think why don't
>> we fix it in libc and libthr, but let kernel returns EINTR?
> 
>> I have worked out a patch:
> 
>> http://people.freebsd.org/~davidxu/patch/sigwait.diff
> 
> The idea and patch seem sensible. Some man page changes seem in order
> though: sigwaitinfo.2 should mention this difference between sigwait()
> and sigwaitinfo() more explicitly.
> 
problem is I still want to know which OS does not return EINTR ?
it seems I can not find one on net, so is it an accident of the
specification group?






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