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From: price@DECWRL.DEC.COM
Newsgroups: comp.windows.x
Subject: Re: X toolkit
Message-ID: <8711102030.AA25250@eros.dec.com>
Date: Tue, 10-Nov-87 17:08:19 EST
Article-I.D.: eros.8711102030.AA25250
Posted: Tue Nov 10 17:08:19 1987
Date-Received: Fri, 13-Nov-87 00:09:17 EST
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Julian Payne asks several questions:


1) How do you register ordinary windows (i.e. not widgets) with the
   dispatcher. If this is not possible then the XtDispatch routine
   should indicate whether or not it used the event?

The current toolkit requires a widget to be registered with the
toolkit. This means that your window must be packaged ( "wrapped" ) in
a widget. The current toolkit does not include a "Window Widget". I expect
that this will appear shortly, since there has already been xpert traffic
discussing the need for such a beast. In the mean time, you must write a
widget to contain you window. The widget doesn't really have to do much
else; it can be a subclass of the Core widget, and you can use the widget
handle to externally register event handlers for expediency.


2) Can more than one function be called automatically by the dispatcher
   for the same widget (or window) and the same event mask?

yes.

3) I have got the text widget to work but I have had some problems
   understanding how it should be used:

   a) When you pass a string to XtTextStringCreate does it use the
        string as a buffer or does it copy the string to its own buffer,
        who is in charge of checking that the buffer does not overflow
        and dealing with it when the end of the buffer is reached?

It uses the string as a buffer. It does not copy it. This is probably
not a good idea, but that's the way it currently works. The Text widget
is *supposed* to handle overflow checking, but it currently doesn't. This is 
not a feature.

     b) What I want to do is have a XttextAppend widget where I can send
        it a prompt and then type commands in which I can send to the
        application every time I get a newline. The text widget is
        wonderful for appending text and moving through the text (I love
        the emacs-type functionality) but it seems very hard to get
        information back about what I typed. At the moment I have to
        check key press events and maintain my own buffer, I can't read
        the data itself because I need to distinguish between what the
        user typed and what the application printed.

You should be able to achieve this functionality by using the translation
manager. At least that is the intent. Unfortunately, the current text
widget does not list a DoCallback() function in its textActionsTable (Text.c).
The simple fix is for you to add this function yourself. You would then
specify that the RETURN key inserts and also calls back in your .XtActions
file, or in an ActionsTable you pass when you create the text widget.

This needs to be fixed in a future release. (I can't commit MIT to this,
but I expect it will probably happen).

     c) I assume that the only way for the application to put text into the
        widget is by using XtTextReplace, if this is so and the function
        is public then the typedef for XtTextBlock should be in Text.h
        and not TextP.h? (XtTextBlock is the type of one of the arguments)

Yes, it should be in Text.h.

4) Do I need to write my own forms or will they appear with the next release?

A forms widget should appear in the next release (Here I go committing 
MIT again, though). It's port didn't make the deadline for this release.

Should this type of query go straight to the toolkit people? If the answer
is yes could someone tell me who the correct person to send queries to is??

This type of query is definitely appropriate here. We (toolkit group) will
make every effort to respond promptly.

-chuck