Vads X/Motif & C

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

Folks --

I'm attempting to interface Ada with an X/Motif government 
application written in C.  I'm using Vads Ada (V6.2.3) and 
Vads Ada X Interface to Motif (V3.2.3) The platform is a 
Sparcstation 20 running Solaris 2.4.

Initially I had dynamic allocation problems due to the
ways Vads and Solaris were performing memory allocation.
I believe I have this solved by modifying the v_usr_confb.a file
to use malloc() instead of sbrk() in the kernel allocation
function V_KRN_ALLOC_CALLOUT.  After this was done, I no
longer get segmentation faults after malloc calls in the
government C software.

However, I'm still getting segmentation faults during various
X/Motif calls, and I'm not 100 percent sure that the above
fix has totally addressed the problem of the interaction of the
Vads Ada runtime and Solaris OS in regards to memory allocation.
Does anyone have any "lessons learned" from doing similar work ??

I'm also running in problems such as getting a resource's value 
from a widget, then immediately setting the widget's resource to
the same value, and getting a segmentation fault.  For Example:

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)

Any suggestions as to why this happens ??

Thanks





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 **