Re: [Erlyaws-list] Problem running websockets_example_endpoint.yaws

[Steve V. <vi...@ie...>]

Glad to hear it's working.

The easiest way to build everything with debug might be to use make,
since there you can just say

make debug

which basically adds -Ddebug +debug_info to the Erlang compiler (and
also builds the C code with -g). To be able to run make, you first
have to

autoconf
./configure
make debug

Our rebar support is still not as capable as our make support, but
we're getting there. The make support has had a 10 year head-start.
:-)

Another way to see what's going on would be to use dbg tracing. Takes
a bit to learn, but personally I find dbg to be far more useful than
the debugger for most Erlang debugging. Chapter 17 of Francesco's and
Simon's "Erlang Programming" book is a good way to learn it.

--steve

On Fri, Feb 17, 2012 at 3:13 PM, George Stoianov <gst...@gm...> wrote:
> On 02/17/2012 08:42 PM, Steve Vinoski wrote:
>
> On Fri, Feb 17, 2012 at 1:52 PM, George Stoianov <gst...@gm...>
> wrote:
>
> Hi guys,
>
> I just cloned the git repo and I am trying to run the websocket example
> and I get this
>
> =ERROR REPORT==== 17-Feb-2012::19:47:38 ===
> Error in process <0.103.0> with exit value:
> {undef,[{basic_echo_callback,handle_message,[{text,<<16
> bytes>>}]},{lists,map,2},{yaws_websockets,loop,4}]}
>
> Typically when you see an "undef" error like this, it means that the
> module or function in question doesn't exist or hasn't been loaded.
>
> If you're running yaws -i, try hitting enter and you should see an
> Erlang shell prompt. At that prompt type
>
> code:which(basic_echo_callback).
>
> and hit enter. Make sure you include the period at the end. If that
> module is available, it will tell you its file system pathname. But if
> it's not found, you'll get the response non_existing.
>
> It looks like the rebar build isn't compiling this module, which we'll
> have to fix. If you want to compile it by hand, you can go into the
> examples/src directory and type
>
> erlc -I../../include -o ../../ebin *.erl
>
> and get both modules built. Their compiled beam files will go into the
> top-level ebin directory. Things should then work better.
>
> --steve
>
> Thanks Steve,
>
> I noticed right after I send my email that ebin did not contain that file so
> I compiled it, moved it and restarted, bingo it works.
> Could not figure out what I have to change to rebar.config to make it
> compile the example.
>
> Thanks for the prompt response and for working on Yaws. I am new at Erlang,
> but from all the things I have read I like it and yaws is really nice
> for the moment I only serve small stuff like photos etc.. but I would like
> to learn more about how it works under the hood. Is there a way I can
> specify a flag so all artifacts are build with debug_info and I can look at
> things with the debugger??
>
> Thanks,
> George
>
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