[C++-sig] Re: Multiple typeinfos causing failure of exception catches

[Niall Douglas]

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A little more on this:

[ned at katey2 lib]$ ./TestEmbedPython
TnFOX Python test:
- -=-=-=-=-=-=-=-=-Working with Python 2.3 (#8, Jul 10 2004, 11:28:33)
[GCC 3.4.0]
If you can read this, python prints!
Typeinfo of FXException in DLL is 0x804cba0,0x41f65004 
(N2FX11FXExceptionE)
Typeinfo of FXPythonException in DLL is 0x804a9d8,0x804a9e4 
(N2FX17FXPythonExceptionE)

Throwing a python exception ...
Typeinfo of caught exception in DLL is 0x804a9d8,0x804a9e4 
(N2FX17FXPythonExceptionE)
C++ exception caught: exceptions.IOError,A parameter to a python 
exception at line 2 in <string> (code 0xFFDE)

Typeinfo of pointer to be returned from DLL is 0x804a9d8,0x804a9e4 
(N2FX17FXPythonExceptionE)
Typeinfo of pointer returned from DLL is 0x804a9d8,0x804a9e4 
(N2FX17FXPythonExceptionE)

Typeinfo of FXException in EXE is 0x804cba0,0x41f65004 
(N2FX11FXExceptionE)
Typeinfo of FXPythonException in EXE is 0x804a9d8,0x804a9e4 
(N2FX17FXPythonExceptionE)

Throwing a python exception ...
terminate called after throwing an instance of 
'FX::FXPythonException'
Deleted secure heap

Unhandled Signal 0x6 (Abnormal termination)
    at address 0x5979 - immediate exit!


What I've done here is copy the throw/catch code into the bindings 
shared object. As we can see, the first throw/catch works fine and 
the second dies with terminate(). Both sets of code are identical - 
just in the second the throw is in the bindings DLL and the catch is 
in the EXE.

I have it printing the address of the typeinfo, the typeinfo.name() 
address and then the string. I was surprised to see that in both the 
DLL and EXE all addresses are the same, so therefore typeinfo 
comparison by address should be working. Therefore it would seem that 
this bug is not the same as Dave's original one.

I'll investigate GCC's source code next, maybe get it printing what 
the hell it's up to when it's catching exceptions. I've already 
looked through the assembler output from GCC for each of the source 
files and I'm fairly confident it's not that - also, a mockup of the 
same DLL & EXE configuration works fine so I think it's the linker, 
perhaps because it's linking 120Mb of non-debug object files with 
nearly 160,000 symbols.

Cheers,
Niall





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