This is the mail archive of the
mailing list for the glibc project.
Re: [PATCH][BZ #15790] Have pthread_mutexattr_gettype mask out the elision bit.
- From: Cesar Philippidis <cesar at codesourcery dot com>
- To: Rich Felker <dalias at aerifal dot cx>
- Cc: Andi Kleen <andi at firstfloor dot org>, OndÅej BÃlka <neleai at seznam dot cz>, <libc-alpha at sourceware dot org>
- Date: Mon, 11 Nov 2013 10:31:50 -0800
- Subject: Re: [PATCH][BZ #15790] Have pthread_mutexattr_gettype mask out the elision bit.
- Authentication-results: sourceware.org; auth=none
- References: <5266B4C3 dot 3090106 at codesourcery dot com> <20131107121529 dot GA17527 at domone> <20131107175715 dot GM29695 at two dot firstfloor dot org> <20131108041730 dot GY24286 at brightrain dot aerifal dot cx> <5281007C dot 7030201 at codesourcery dot com> <20131111174905 dot GL24286 at brightrain dot aerifal dot cx>
On 11/11/13, 9:49 AM, Rich Felker wrote:
> On Mon, Nov 11, 2013 at 08:06:20AM -0800, Cesar Philippidis wrote:
>> On 11/7/13, 8:17 PM, Rich Felker wrote:
>>> On Thu, Nov 07, 2013 at 06:57:15PM +0100, Andi Kleen wrote:
>>>>> Andi, it is unclear that if this is desired behaviour, one argument
>>>>> againist could be that if user wants to clone mutex type like
>>>>> int tp;
>>>>> pthread_mutexattr_gettype(a1, &tp);
>>>>> pthread_mutexattr_settype(a2, tp);
>>>>> should it preserve elision or not?
>>>> Yes it should.
>>> Sorry, it can't. The interface contact is set by POSIX, not something
>>> for glibc to design.
>> I'm confused. Is it OK for pthread_mutexattr_gettype() mask out the non
>> portable elision bits, PTHREAD_MUTEX_NO_ELISION_NP and
>> PTHREAD_MUTEX_ELISON_NP, set by pthread_mutexattr_settype()?
> Your question is misleading. As far as I understand,
> pthread_mutexattr_settype does not, from an application perspective,
> "set the elision bits of type". It sets the type, which might, due to
> the semantic requirements of the type, require forcing elision off, or
> allow a default of elision-on to be applied. As an implementation
> detail, this elision state is stored in the type field, but it is not
> part of the type. pthread_mutexattr_gettype must return the exact
> value that was passed to pthread_mutexattr_settype, nothing else.
OK, so then pthread_mutexattr_settype needs to be corrected not to set