_IO_MTSAFE_IO

[Joseph Myers]

On Fri, 29 Apr 2016, Florian Weimer wrote:

> Whether applications can use these macros is somewhat debatable, but as I
> said, it happens within glibc as well.  There are repeated occurrences of this

My view would be:

* libio is not a public API for applications; only stdio is (and internals 
should be avoided in public headers where possible).  But ABI 
compatibility with old applications using libio may still be needed.

* _IO_* symbols may be used internally in glibc for namespace reasons 
(where they are function aliases), or if there is another reason for using 
internals of another part of glibc.

> Curiously, _IO_flockfile and _IO_funlockfile are only defined in
> libpthread.so, not in libc.so.  But these implementations are slightly

They seem to be in the libc.abilist files to me....

-- 
Joseph S. Myers
joseph@codesourcery.com