[PATCH 4/4] posix: Implement preadv2 and pwritev2

[Joseph Myers]

On Thu, 27 Apr 2017, Adhemerval Zanella wrote:

> The Linux one uses the preadv2/pwritev2 syscall if defined, otherwise it
> call preadv/writev.  Instead of using the previous __ASSUME_* to
> unconditionally issue the syscall (and avoid building the fallback routine),
> it call pread/write if the preadv2/pwritev2 syscalls fails.  The idea
> is just avoid adding another __ASSUME_* and checking each architecture
> on every kernel bump and simplify code conditionals.

I think we should have the __ASSUME_*; it's how we track when code can be 
removed after an increase to the minimum supported kernel version (unless 
you have some other way of the community tracking code that will become 
obsolete after such a change).

What's the rationale for missing documentation for these functions?  That 
preadv and pwritev are also missing documentation?

-- 
Joseph S. Myers
joseph@codesourcery.com