Re: futex(2) man page update help request

From: Michael Kerrisk (man-pages)
Date: Thu May 15 2014 - 09:47:06 EST


On 05/15/2014 07:21 AM, Darren Hart wrote:
> On 5/14/14, 17:18, "H. Peter Anvin" <hpa@xxxxxxxxx> wrote:
>
>> On 05/14/2014 09:18 AM, Darren Hart wrote:
>>>
>>> However, unless I'm sorely mistaken, the larger problem is that glibc
>>> removed the futex() call entirely, so these man pages don't describe
>>> something users even have access to anymore. I had to revert to calling
>>> the syscalls directly in the futextest test suite because of this:
>>>
>>>
>>> http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git/tree/inc
>>> lu
>>> de/futextest.h#n67
>>>
>>
>> This really comes down to the fact that we should have a libinux which
>> contains the basic system call wrapper machinery for Linux specific
>> things and nothing else.
>>
>> syscall(3) is toxic and breaks randomly on some platforms.
>
> Peter Z and I have had a good time discussing this in the past.... And
> here it is again. :-)

People have a number of times noted that there are problems
with syscall(), but I'm not knowledgeable on the details.
I'd happily take a patch to the man page (which, for historical
reasons, is actually syscall(2)) that explains the the problems
(and ideally notes those platforms where there are no problems).

Thanks,

Michael


--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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