Re: [RFH] Flush progress message buffer in display().

From: Junio C Hamano <gitster@pobox.com>
Date: Nov 19, 2007, 22:09 UTC
Message-ID: <7vk5odnazh.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <alpine.LFD.0.99999.0711191549510.19105@xanadu.home>

Nicolas Pitre <nico@cam.org> writes:

Show 12 quoted lines

> On Mon, 19 Nov 2007, Junio C Hamano wrote:
>
>> The standard error stream is not "fully buffered":
>> 
>>     http://www.opengroup.org/onlinepubs/000095399/functions/xsh_chap02_05.html#tag_02_05
>> 
>> Not "fully buffered" means either "unbuffered" or "line
>> buffered".  Because the progress display does not terminate its
>> line, it means that the additional fflush(stderr) you added are
>> needed if the stream is line buffered (still conforming).
>
> Maybe stdio on Linux considers \r as a line termination.

Or totally unbufferred.  Running strace on this:

        #include <stdio.h>

        int
        main(int ac, char **av)
        {
                fprintf(stderr, "foo");
                fprintf(stderr, "bar");
                return 0;
        }

will tell you. I bet you will see two write(2) of 3 bytes each.

> Flushing stderr should not hurt anyway.

True, especially if the rate is limited, which it is.