Vads X/Motif & C

[msb@sei.cmu.edu (Mark Bell)]

Thanks to all who responded to my questions, either via private
email or this newsgroup.

Most of the suggestions I had already tried, but I was glad to
see that I was at least looking in the correct areas.  I've
done Ada for many years, but this is the first time I've had
to deal with X/Motif, let alone interfacing to it from Ada !

I can not change the malloc() calls to Xtmalloc() calls in the
C source code, as the C code is "off the shelf".  Even though
I have some of the source for reference, changing it is not
an option.

Several folks asked some further questions about my application.
The C code is from the U.S. Army, and is called TEM (Terrain Evaluation
Module V 9.3.1).  It consists of main program which spawns several
servers.  It comes with a C-based GUI interface.  As received,
the application and GUI seems to work fine on the Solaris platform.
(Can I infer that the malloc vs xtmalloc issue is not a problem
here, or that it just hasn't surfaced yet?  The C code does
use malloc).

We (at the SEI) have written a Convoy Planning Prototype in Ada 83.
This uses the VADS X/Motif interface.  The initial versions used 
a line map for Convoy routing purposes.  These versions run fine
on the Solaris platform.

We are attempting to replace the line map with the actual
geographical maps and accompying services offered by TEM.
Thus, we need to bypass the provided GUI and use our own.
This is where the problems are.

Concerning the following code segment
 
> Xt.Xt_Resource_Management.Xt_Set_Arg(
>   Arg => An_Arg_List(0),
>   Name => Xt_Stringdefs.Xt_N_background,
>   Value => blank_color'Address);
> 
> Xt.Xt_Resource_Management.Xt_Get_Values(
>   W    => Presentation_Drawing_Area,
>   Args => An_Arg_List(0..0));
> 
> Xt.Xt_Resource_Management.Xt_Set_Values(
>    W    => Presentation_Drawing_Area,
>    Args => An_Arg_List(0..0));
> 
> (Segmentation fault occurs)
> 
I was not surprised to see that it was such an obvious goof...
another case of not seeing the trees in the forest !  I wondered
why this was the only place that I had trouble with the
Xt_Set_Value function.

Thanks again...




Mark S. Bell                           412-268-7925 (Voice)
Software Engineering Institute         412-268-5758 (Fax)
Carnegie Mellon University             ** These are my opinions, 
4500 Fifth Ave, Pittsburgh PA.,15213      not those of the SEI or CMU **