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Re: [PATCH] Unbuffer stdout and stderr on windows
- From: Christopher Faylor <cgf-use-the-mailinglist-please at sourceware dot org>
- To: Pedro Alves <palves at redhat dot com>, gdb-patches at sourceware dot org, yao at codesourcery dot com, Joel Brobecker <brobecker at adacore dot com>, Eli Zaretskii <eliz at gnu dot org>
- Date: Tue, 13 Aug 2013 13:28:42 -0400
- Subject: Re: [PATCH] Unbuffer stdout and stderr on windows
- References: <1374462417-7961-1-git-send-email-yao at codesourcery dot com> <838v0yy556 dot fsf at gnu dot org> <51EE23F8 dot 1070905 at codesourcery dot com> <83wqohw4ee dot fsf at gnu dot org> <20130729192559 dot GA5348 at ednor dot casa dot cgf dot cx> <83d2q1xiyv dot fsf at gnu dot org> <51F6C7B2 dot 3020400 at redhat dot com> <20130731034045 dot GA5565 at ednor dot casa dot cgf dot cx> <20130812211105 dot GA11128 at adacore dot com>
On Mon, Aug 12, 2013 at 02:11:05PM -0700, Joel Brobecker wrote:
>> We had a somewhat heated debate in the cygwin list about using the
>> techniques in winpty and eventually abandoned the idea because the way
>> things like winpty create consoles is not foolproof. Since it relies on
>> polling, it is theoretically possible to lose data.
>>
>> I'll bet that, in practice you'd never see any data loss, though.
>> And, from that observation, you can see which side of the argument
>> I was on. :-)
>
>FWIW, many frontends also implements communication with GDB using
>pipes on Windows, and running MinGW-gdb inside cygwin window/shell
>is just a very very common practice, regardless of whether officially
>supported or not. How does Emacs do, for instance? IIRC when I looked
>at the code, that's what it did.
>
>Having the stdout/stderr output mixed up is very confusing and breaks
>testing as well, so we applied the same approach as Yao's at AdaCore.
>In the many many years that we've used this approach, no one ever
>complained to us about standard I/O performance.
>
>For completeness, our calls to setvbuf are inserted about 10 lines
>later, after gdb_stdout/gdb_stderr are set up.
So do you just unconditionally set gdb_std* to unbuffered? I would
think that this would be nearly unnoticeable.
cgf