Re: [PATCH] Speed up "gdb -tui" output

Eli Zaretskii
2015-01-07T18:34:01Z

> Date: Wed, 7 Jan 2015 10:09:03 -0800
> From: Doug Evans <dje@google.com>
> Cc: Pedro Alves <palves@redhat.com>, gdb-patches <gdb-patches@sourceware.org>
>
> >> Should it be calling wrefresh if the file is gdb_stdout?
> >
> > Only if that stream is a real file, not a string or whatever else we
> > support in ui-file.
>
> tui_file_flush only gets called for tui files

That's not really true, as you yourself point out:

> Though I see tui also has its own ui file strings (tui_sfileopen).
> That can go I think.

I don't see how it could go: it's used.

> >> If we do that, and change tui_puts like:
> >>
> >> - /* We could defer the following. */
> >> - wrefresh (w);
> >> - fflush (stdout);
> >> + if (c == '\n')
> >> + gdb_flush (gdb_stdout);
> >>
> >> would it work?
> >
> > No, it's not enough. There's also gdb_stderr and gdb_stdlog, at
> > least. (tui_puts doesn't get the stream as its argument, so it
> > doesn't really know which stream it is serving.) I'm trying to make
> > heads or tails out of this, but I'm not there yet.
>
> Sure, but it does suggest tui_puts is the wrong place to do
> any kind of flushing/refreshing.

How else can you emulate the unbuffered nature of gdb_stderr and the
line-buffered nature of gdb_stdout, for example? The GDB application
code implicitly expects that.