[PATCH v3 2/2] posix: Implement preadv2 and pwritev2

H.J. Lu hjl.tools@gmail.com
Sat Jun 3 14:16:00 GMT 2017


On Sat, Jun 3, 2017 at 6:58 AM, Zack Weinberg <zackw@panix.com> wrote:
> On 06/03/2017 09:52 AM, H.J. Lu wrote:
>> On Sat, Jun 3, 2017 at 6:48 AM, Zack Weinberg <zackw@panix.com> wrote:
>>> If nothing else, always passing the unused argument as 0 will reduce
>>> confusion when people inspect these syscalls, e.g. through the debugger
>>> interface or the seccomp filter interface.  I think that's a sufficient
>>> reason to do it.  These are all I/O syscalls that can block, it's the
>>> wrong place to be shaving cycles.
>>
>> LO_HI_LONG_FLAGS is still needed for x32, regardless what we
>> do with LO_HI_LONG.
>
> But x32 won't get the definition of LO_HI_LONG that expands to "(val),
> 0)" - that would be wrong - so why won't LO_HI_LONG(val), flags work?
>

X32 inherits LO_HI_LONG from x86-64.  If we change x86-64
LO_HI_LONG, x32 needs to redefine LO_HI_LONG.


-- 
H.J.



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