Re: [Caml-list] Native multithreaded LablGTK2?

[Kaspar Rohrer <krohrer@student.ethz.ch>]

On 30.07.2007, at 13:57, Julien Moutinho wrote:

> Oki douki, it's just that I did not undertand why you use std(in|out)
> to communicate between threads... But you use them because you want
> a buffering machinery and you have only looked at Pervasives, right?
No, the problem is of a different nature: I want to capture standard  
output and display it in a (log) window in my Gtk application. I'm  
aware that I could just use custom output functions, but the main  
problem here is that I've embedded a Scheme interpreter (Ocs,  
actually: http://will.iki.fi/software/ocs/) which writes to stdout by  
default. Now, of course I could adapt Ocs to suit my needs. But I  
have no intention to do so at the moment (although it would be  
relatively straight forward by extending Ocs_port).

>> I'm piping stdout, because that's the only way I was able to redirect
>> stdout to a gtk text widget (using a GIOchannel: GMain.Io.*). If  
>> anybody
>> has a better idea, I'd be glad to hear it. I was originally  
>> thinking of  an
>> out_channel that writes to a buffer instead of a file, but the Ocaml
>> standard library seems to be missing this functionality. Or is it?
> You have [Stream.t], [Buffer.t] and [GText.buffer] at your service.
>
> HTH.
I actually already use a GText.buffer. In conjunction with piping and  
GMain.Io.add_watch, I am able to redirect standard output to the  
buffer and thus display it in a text widget. But this only works  
reliably if the application is multithreaded, because pipes have a  
fixed size buffer (something around 5000 bytes IIRC). Now, if the  
buffer was able to capture all output, this would work for a single  
thread also. Because writes to the buffer would never block, unlike  
writes to a pipe.
I might be wrong on all of the above though, as I am far from an  
expert on either Gtk or multithreading.

Anyway, thanks again. I really apreciate any help I can get.