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

[Zack Weinberg]

On Tue, Jul 11, 2017 at 1:56 PM, Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
> Ping (x2). I think something we won't bother to emulate solaris behaviour,
> so in a short we should document it and close it.

I agree that existing behavior should not be changed, but the text you
proposed for the manual doesn't make a lot of sense unless you already
know what the problem is.

>>> +On Linux the stack information return on @code{uc_stack} is empty by
>>> +default.  It also the case for signal handling information through
>>> +@code{sigaction} with @code{SA_SIGINFO}.  It could be obtained using
>>> +architecture specific field from @code{uc_mcontext} member.

@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.

The detail regarding 'sigaction' belongs in the documentation for
'sigaction', and we currently don't document SA_SIGINFO at all, so I
would just leave that bit out.

zw