Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!richsun!joan
From: joan@richsun.UUCP (Joan Siebenaler)
Newsgroups: comp.windows.x
Subject: Problem with X Shared Libraries
Message-ID: <389@richsun.UUCP>
Date: 13 Jun 89 16:20:29 GMT
Reply-To: joan@richsun.UUCP (Joan Siebenaler)
Distribution: na
Organization: RICH Inc., Franklin Park, IL
Lines: 29

I've had a problem running programs linked with the X built Shared
Libraries on Sun machines.  The problem is in the Xt code.  When a widget
sets a procedure in it's class record to inherent the parents procedure
the _XtInherit error function is called and exits.

The widget initialization code does a compare of the _XtInherit address
with the value stored in the Widget's class record.  The XtInherit
procedures XtInsertChild, XtInheritResize, XtRealize, etc. are define
as the _XtInherit procedure.  In the widgets class initialization if 
the value stored in the class record is equal to the _XtInherit function
address the widget's parent procedure address is stored in the class
record.  When the Xt library is built as a shared library  the _XtInherit 
address is resolved to a library branch table entry and is not equal to
the value set in the widgets class record.  The conditional branch is not
taken and the widget's parent procedure is not inherited.

To fix this problem I defined all the XtInherit procedures to a constant
and defined _XtInherit equal to the same constant.  This flags the widget 
initialization to inherit the parents procedure and an address comparison
is not done.

Has anyone else out there had this problem.  Should the link editor be able
to resolve the address comparison of a shared library procedure with the 
procedure address stored in the non-shared code, or should address
comparisons not be done.  

Thanks for any help or comments you can give me.
 
Joan Siebenaler   (312) 455-6100, ext 621    uunet!richsun!joan