On Mon, 27 Jun 2016 at 22:47:59, Nicolas Pitre wrote:
> On Mon, 27 Jun 2016, Lukas Fleischer wrote:
>
> > On Mon, 27 Jun 2016 at 19:50:13, Junio C Hamano wrote:
> > > Jeff King <peff@xxxxxxxx> writes:
> > >
> > > > On Mon, Jun 27, 2016 at 08:54:22AM -0700, Junio C Hamano wrote:
> > > >
> > > >> It's just you used xwrite() there that introduced a different issue.
> > > >> Wouldn't replacing it with fwrite(stderr) without changing anything
> > > >> else solve that?
> >
> > I do not see how using fwrite() buys us anything. Neither fwrite() nor
> > fputs() nor fprintf() guarantee to call write() only once. Each of these
> > three functions is buffered when printing to stdout and unbuffered when
> > printing to stderr.
>
> You are right. However, in practice:
>
> - fprintf(stderr, "%s", buffer) is likely to call write() only once
> given there is only one string specifier, and
>
> - On Windows the ANSI escape sequences are interpreted by fprintf() and
> not by write() nor by the actual display console code. Insane but such
> is life sometimes.
>
> So the point is simply to replace your call to write() by a call to
> fprintf(..., "%*s", ...) in your patch which should provide the same
> end result as before.
Well, this is essentially what I tried to make clear in my previous
email. In practice, each of the following lines should work:
fwrite(outbuf.buf, 1, outbuf.len, stderr);
fputs(outbuf.buf, stderr);
fprintf("%s", outbuf.buf, stderr);
fprintf("%.*s", outbuf.len, outbuf.buf, stderr);
The first version is probably to most "efficient" one and I personally
find the fputs() line to be the one that is easiest to read. However, I
think it does not make sense to start another bikeshedding discussion at
this point. I will make a defensive choice and use fprintf() with "%.*s"
since that is what we used before, so it is tested well enough.
Given the amount of discussion required to get this right, I also
strongly believe this code deserves a comment with a short explanation
on why things are done this way...
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