code review 5700070: cmd/dist: force line-buffering stdout/stderr on Unix

cmd/dist: force line-buffering stdout/stderr on Unix
        If stdout and stderr are indeed the same file (not a tty), which is
        often the case, fully-buffered stdout will make it harder to see 
        progresses, for example, ./make.bash 2>&1 | tee log

[minux1, 2012-02-25 19:06:34]

Hello golang-dev@googlegroups.com (cc: golang-dev@googlegroups.com),

I'd like you to review this change to
https://code.google.com/p/go/

[r, 2012-02-28 00:28:49]

i like it as is. if we don't buffer, someone will come back and add buffering.
you can't win.

leaving for rsc.

[minux1, 2012-02-28 04:46:15]

On 2012/02/28 00:28:49, r wrote:
> i like it as is. if we don't buffer, someone will come back and add buffering.
> you can't win.
OK, then I changed it to force line buffering. It still fix my problem,
and additional benefit is that it matches the Windows version.

[rsc, 2012-02-28 17:13:58]

http://codereview.appspot.com/5700070/diff/3003/src/cmd/dist/unix.c
File src/cmd/dist/unix.c (right):

http://codereview.appspot.com/5700070/diff/3003/src/cmd/dist/unix.c#newcode644
src/cmd/dist/unix.c:644: setvbuf(stdout, nil, _IOLBF, 0);
I don't believe this is available on OS X.
I spent a while fighting the buffering and trying to 
write something that would work on all the relevant
systems.  It might be better left alone.

[minux1, 2012-02-28 17:23:45]

On 2012/02/28 17:13:58, rsc wrote:
> http://codereview.appspot.com/5700070/diff/3003/src/cmd/dist/unix.c
> File src/cmd/dist/unix.c (right):
> 
> http://codereview.appspot.com/5700070/diff/3003/src/cmd/dist/unix.c#newcode644
> src/cmd/dist/unix.c:644: setvbuf(stdout, nil, _IOLBF, 0);
> I don't believe this is available on OS X.
I‘ve just tested this on Mac OS X 10.6.8/amd64, and it works as intended.
I've also tested this on Linux/amd64, FreeBSD/amd64 and OpenBSD/amd64,
all is well (my test case is './all.bash 2>&1 | tee /dev/null').

[rsc, 2012-02-28 18:08:27]

LGTM

Maybe I was remembering trouble on Windows, but that doesn't concern this file.
Try it and see I guess.

[minux1, 2012-02-28 18:22:37]

*** Submitted as http://code.google.com/p/go/source/detail?r=eabeb88b4bb7 ***

cmd/dist: force line-buffering stdout/stderr on Unix
        If stdout and stderr are indeed the same file (not a tty), which is
        often the case, fully-buffered stdout will make it harder to see 
        progresses, for example, ./make.bash 2>&1 | tee log

R=r, rsc
CC=golang-dev
http://codereview.appspot.com/5700070

[iant2, 2012-02-28 18:32:28]

rsc@golang.org writes:

> src/cmd/dist/unix.c:644: setvbuf(stdout, nil, _IOLBF, 0);
> I don't believe this is available on OS X.

setvbuf is in C89 and should be available everywhere.

Ian