Re: cygwin.rules - Enabling shared libXt finally?

[Alexander Gottwald <alexander dot gottwald at s1999 dot tu-chemnitz dot de>]

On Wed, 1 Oct 2003, Harold L Hunt II wrote:

> Alexander Gottwald wrote:
> > 
> > Have you tested this with programs which uses libXt and some widgets from
> > another library?
> 
> Yeah, that is what I was saying above.  I built a shared version, made 
> some changes, and rebuilt some clients (xman.exe, xcalc.exe, etc.), but 
> they keep giving the unresolved inheritence error as above.

The location of _XtInherit still differs in dll and program. 

> Actually, if you look at 
> xc/config/cf/ibmLib.rules/SharedLibraryTarget(), you see that 
> sharedlib.o (which is contained in $(UNSHAREDOBJS)) is linked directly 
> into the import library, not into the shared library.  The idea is that 
> each application linked against libXt should end up with one copy of the 
> sharedlib.o code.  Thus, comparisons against _XtInherit will work just 
> fine within one application, which is the only case that we are 
> concerned with.

no. The structures of the dll are initialized with dll_base + x and the 
structures from the program are inititalized with program_base + y. Even
if we find a way to have x == y, the symbols still differ because the 
dll is placed on a different place than the program.

Simple testprogram:

--x.h
typedef void (*func)(void);
extern void _XtInherit(void);
typedef struct { func callback; } x;
extern x x1, x2;
--xtinherit.c
#include "x.h"
void _XtInherit(void) {
}
--x1.c
#include "x.h"
x x1 = { _XtInherit };
--x2.c
#include "x.h"
x x2 = { _XtInherit };
--xtest.c
#include "x.h"
#include <stdio.h>

int main(void) {
    printf("x1.callback: %p\n", x1.callback);
    printf("x2.callback: %p\n", x2.callback);
    return 0;
}
--build.sh
gcc -shared -o x1.dll x1.c xtinherit.c
gcc -o xtest.exe xtest.c x2.c xtinherit.c x1.dll
gcc -o xtest2.exe xtest.c x2.c x1.dll
--output xtest.exe
x1.callback: 0x10001010  
x2.callback: 0x4010d0
--output xtest2.exe
x1.callback: 0x10001010
x2.callback: 0x401750

bye
	ago
-- 
 Alexander.Gottwald@s1999.tu-chemnitz.de 
 http://www.gotti.org           ICQ: 126018723