[pulseaudio-discuss] [PATCH 2/2] Improve set-log-target functionality

[Tanu Kaskinen]

On Mon, 2013-05-20 at 17:17 +0800, Shuai Fan wrote:
> Hi Tanu,
> 
> I'm sorry for not replying to your letter sooner.

No problem at all.

> On 05/14/2013 09:59 PM, Tanu Kaskinen wrote:
> > On Fri, 2013-05-10 at 17:05 +0800, shuai wrote:
> >> ---
> >>   src/daemon/daemon-conf.c    |  74 ++++++-------------
> >>   src/daemon/daemon-conf.h    |   2 +-
> >>   src/daemon/main.c           |  16 +++--
> >>   src/pulsecore/cli-command.c |  48 +++++++------
> >>   src/pulsecore/log.c         | 171 ++++++++++++++++++++++++++++++++------------
> >>   src/pulsecore/log.h         |  20 ++++--
> >>   src/utils/pactl.c           |  18 +----
> >>   7 files changed, 202 insertions(+), 147 deletions(-)
> >>
> >> diff --git a/src/pulsecore/log.c b/src/pulsecore/log.c
> >> index 1aa8b0e..a2b9f54 100644
> >> --- a/src/pulsecore/log.c
> >> +++ b/src/pulsecore/log.c
> >> @@ -48,6 +48,7 @@
> >>   
> > Patch 1/2 added fcntl.h include here. Out of curiosity, what is that
> > needed for?
> 
> For function open() and file open flags like O_CREAT.

OK, makes sense.

> Thank you very much for replying me patiently.
> I'm sorry for lots of problems in this patch, I tried a new patch these 
> days after receiving your letter.
> 
> Can I ask you some questions, please?
> 
> First, can you tell me how to debug large programs, please? Currently, I 
> use lots of 'printf' to print values in program, but these printfs must 
> be removed when the "debug" is finished. And it is possible some of them 
> may not be removed, which is not expected.

"git add -p" can be helpful. It allows you to review each chunk that
will be added to a commit, so debug prints can be easily skipped. The
debug prints will still be available in the working tree, so you don't
have to lose them completely if you don't want to.

> Also, a large program with 
> makefile, gdb could not be used(maybe just I don't know how to use it).

I guess the problem is that src/pulseaudio isn't the real executable,
it's a shell script generated by libtool. The real executable is
src/.libs/pulseaudio, and gdb can be used with that. In my workflow I
tend to install pulseaudio always before testing, so I can use just "gdb
pulseaudio", but "gdb src/.libs/pulseaudio" should work from the build
directory also without installing.

> Second, about pulseaudio, when I start the program with command 
> "src/pulseaudio -n -F src/default.pa -p $(pwd)/src/ -vvvv", Iots of 
> information prints on the screen, and I want to have a look at all 
> information, but only the last part could be seen. My desktop is ubuntu, 
> in terminal, with scrollbar, I could see the last part too.

Sorry, I'm not sure I follow. Is the problem that your terminal doesn't
have big enough buffer? It can be made bigger (at least with
gnome-terminal, which is the default in Ubuntu). Go to Edit -> Profile
Preferences. The Scrolling tab contains settings for the scrollback
buffer size.

> I tried ">" 
> to prints this information into one file, but failed. I think the reason 
> is the "pulseaudio" is a server, runs and not stops. So, can you tell me 
> how to see all information(especially the beginning of this information) 
> of this kind of program, please? Or only for pulseaudio, how to see all 
> log information when the program starts.

">" redirects only stdout, but the log is printed to stderr. Use "2>" to
redirect stderr to a file.

You can of course also use the file: and newfile: log targets to get the
log in a file.

-- 
Tanu

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