Re: Minimal GCC/Linux shared lib + EH bug example

[loewis at informatik dot hu-berlin dot de (Martin v. Löwis)]

"Ralf W. Grosse-Kunstleve" <rwgk@cci.lbl.gov> writes:

> > I think the message that can be understood by a wider audience is:
> > don't use C++ for Python extension modules.
> 
> Surely You're Joking, Mr. Loewis!

Only half-ly.

> As it stands, Linux/gcc3 is the only platform that does not do what
> we want. Are you sure it is helpful to tell people to "go away"?

For *your* application, only Linux/gcc3 fails to work. For any
compiler/platform combination, I could produce numerous cases that
won't work as many people may expect.

If you want a simple answer, you have to accept the one you I gave. If
you cannot accept this, you must accept that the issues are much more
involved.

> - Is the situation different if python is compiled and linked with a C++
>   compiler (--with-cxx)?

Not on your platform. On other platforms, C++ extensions won't work at
all unless Python is compiled with C++ (AIX, with the system compiler,
is one of these platforms).

> - More generally: What are the issues when using dlopen in any C++
>   program.

Too numerous to list in this message. They roughly group into the
following categories:

- constructor/destructor execution: may or may not execute at dlopen
  time, block-static variables may or may not work correctly.
- duplicate definition of things, where things is one of
  - virtual method tables
  - typeinfo object
  - template instantiations
  - malloc heaps
  - locales
  - ...
- conflicting symbol spaces
- dynamic failures to resolve symbols

Regards,
Martin