Re: `message' not outputting the newline "atomically"

[Paul Eggert]

Eli Zaretskii wrote:
> the loop solution was proposed for those
> few places where we want short messages to go out atomically, but
> without making stderr line-buffered.
>
> What am I missing?

Emacs contains many fprintf calls like this:

  fprintf (stderr, "Using %s\n", term);

Here, TERM is typically a short string. On AIX and Solaris, this fprintf is 
implemented via three 'write' syscalls - one for "Using ", one for the contents 
of TERM, and one for "\n". These outputs will be broken up and hard-to-read on 
AIX and Solaris, if Emacs runs in parallel with other programs also generating 
stderr output. Using line-buffering fixes this.

Essentially, line-buffering is designed to make short output lines atomic, which 
is the problem we are trying to address.