GS application

Francesco Cesarini <>
Wed Oct 25 10:39:37 CEST 2000


Hi Priya,
you have an error in your code. What happens is that a new process is
spawned, but it crashes when executing .

gs:draw_line(Win, solid, 2, Path) 

Which does not exist.

The error is not detected at compile time because Erlang modules are
compiled on a stand alone basis and not linked to each other. 

You can easily find the error by calling internal/0 directly from the
shell
6> line2:internal().
** exited: {undef,{gs,draw_line,
                     
[{5,<0.45.0>},solid,2,[{10,50},{30,50},{30,60},{60,60}]]}} **
7> 

Other errors include the fact that line takes a canvas as a parent and
not a Window. Look at the online documentation @
http://www.erlang.org/doc/current/lib/gs-1.3.7/doc/index.html for exact
parameters to pass to the function.

Regards,
Francesco
-- 
Francesco Cesarini

Erlang/OTP consultant
Cellular: INT+44-7776 250381 
ECN: 832-707192
http://welcome.to/cesarini.consulting

Priya Paramasevam wrote:
> 
> hello
> 
> i did it again .. i accidentally sent the mail without completing it.
> i have compiled and run some of the example programs provided together
> with GS. they run fine. but when i test a simple program that i wrote
> myself, i can't seem to see the output.
> 
> here is my code:
> 
> -module(line2).
> -export([start/0, internal/0]).
> 
> start() ->
>         spawn(line2, internal, []).
> 
> internal() ->
>         I = gs:start(),
>         Win = gs:window(I, [{title, "Demo"}, {width, 200}, {height,
> 270}]),
>         Path = [{10,50}, {30, 50}, {30, 60}, {60, 60}],
>         gs:draw_line(Win, solid, 2, Path),
>         gs:config(Win, {map, true}).
> 
> there isn't any problem compiling, but there is no output. can you please
> tell me what is wrong?
> 
> thank you so much and sorry for the redundant meaningless mails.
> 
> Kind Regards,
> Priya Paramasevam
> Master of Applied Science (IT)
> RMIT University,
> Melbourne, Australia.
> 
> 
> ==========================================================================
>   A good sense of humour, a big dose of patience, and a dash of humility,
>                    you will be rewarded many-fold!
> ==========================================================================
> 
> On Tue, 24 Oct 2000, Simon Bennett wrote:
> 
> > Gerald Biederbeck wrote:
> >
> > > I installed GS and Erlang too.
> > > It works fine.
> > >
> > > Priya Paramasevam wrote:
> > >
> > > >   I am using Erlang to develop a simulation. I need to use GS for this. I
> > > > have installed Erlang and GS on my computer. Unfortunately, I am not able
> > > > to view the GS window.
> >
> > What I think Gerald is saying is that you have not given people on the
> > list much to go on....
> >
> > For example:
> >
> > What operating system are you using?
> >
> > What version of Erlang are you using?
> >
> > Is OTP installed as part of the Erlang installation or separately?  If
> > the latter, have you installed it?
> >
> > What have you actually done to test it?  Run an existing program?
> > Written your own program?  Entered commands in the shell?
> >
> > What was the response?  Did any error messages appear anywhere?
> >
> > Simon Bennett
> > Information Systems Consultant
> > ___________________________________________________________________
> >
> >  Simon Bennett            E-mail:     
> >  Ericsson Intracom        http://www.ericsson.co.uk/UK/intracom
> >  1 Bede Island Road       Voice (UK)  0116 2542400
> >  Leicester                Voice (int) +44 116 2542400
> >  England                  Voice ECN:  832 707 ext 232
> >  LE2 7EU                  Fax:        +44 (0)116 2046111
> > ___________________________________________________________________
> >



-- 
Francesco Cesarini

Erlang/OTP consultant
Cellular: INT+44-7776 250381 
ECN: 832-707192



More information about the erlang-questions mailing list