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Re: [PATCH] manual: Document getcontext uc_stack value on Linux [BZ #759]

• From: Zack Weinberg <zackw at panix dot com>
• To: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
• Cc: GNU C Library <libc-alpha at sourceware dot org>
• Date: Tue, 8 Aug 2017 14:30:10 -0400
• Subject: Re: [PATCH] manual: Document getcontext uc_stack value on Linux [BZ #759]
• Authentication-results: sourceware.org; auth=none
• References: <1494961861-30734-1-git-send-email-adhemerval.zanella@linaro.org> <6d9cf350-c221-3fac-0088-384b42c45adb@linaro.org> <77500c0f-e6f6-43b8-b7b3-b3af65a5b968@linaro.org> <CAKCAbMiS7Ep7MhanttLCZ5VLTGBR3w92gPqckxBmeJh-PHkzHw@mail.gmail.com> <c4cc7c82-9d91-d678-f300-8a663867766f@linaro.org> <CAKCAbMiwk76D5fWeEci5=BTBnwX5u=v56EQT80JzBkWau6Tg3A@mail.gmail.com> <c237e67a-2b5b-672c-cc5d-444ba30e7923@linaro.org> <c3d2af59-9a26-1297-f867-2befe9a4a344@linaro.org>

On Tue, Aug 8, 2017 at 2:27 PM, Adhemerval Zanella<adhemerval.zanella@linaro.org> wrote:> On 11/07/2017 18:43, Adhemerval Zanella wrote:>> On 11/07/2017 17:25, Zack Weinberg wrote:>>> On Tue, Jul 11, 2017 at 2:28 PM, Adhemerval Zanella>>> <adhemerval.zanella@linaro.org> wrote:>>>>>>>> Right, I do not have a preference here about the wording but I do think>>>> we should at least document Linux behaviour (which originated the bug>>>> report). What about:>>>>>>>> @strong{Compatibility Note:} Depending on the operating system,>>>> information about the current context's stack may be in the>>>> @code{uc_stack} field of @var{ucp}, or it may instead instead be in>>>> architecture-specific subfields of the @code{uc_mcontext} field.>>>> On Linux the current context's stack returned on @code{uc_stack}>>>> is empty by default.>>>>>> I actually think we _shouldn't_ document Linux's behavior in this>>> case.  Without a great deal more verbiage about how to write code that>>> portably examines the result of getcontext, it's better to just say>>> "this information could be in two different places" than "this>>> information could be in two different places, and on system X it's in>>> this one."  Good code has to be prepared to look in both places.  That>>> is the best _short_ advice.>>>> Taking in consideration getcontext is deprecated and this is specific>> implementation detail I think it is still worth to mention Linux behaviour>> without the need of extending how to proper use this API (which should>> not be used in newer programs anyway and in my experience the program>> that still rely on such *context, libgo for instance, already have a>> lot of hacks for different systems). The manual imho should mainly>> document the current system supported and its idiosyncrasies.>>>> Zack do you still think we should not document Linux behaviour? I> understand your point that for document getcontext in a portable> way it would require more explanation, but I think the goal here> is just document this specific Linux difference for this deprecated> symbol.I would still prefer to just say>>>> @strong{Compatibility Note:} Depending on the operating system,>>>> information about the current context's stack may be in the>>>> @code{uc_stack} field of @var{ucp}, or it may instead be in>>>> architecture-specific subfields of the @code{uc_mcontext} field.and no more.zw

• Follow-Ups:
  • Re: [PATCH] manual: Document getcontext uc_stack value on Linux [BZ #759]
    • From: Adhemerval Zanella

• References:
  • Re: [PATCH] manual: Document getcontext uc_stack value on Linux [BZ #759]
    • From: Adhemerval Zanella