[Python-Dev] Python + Visual C++ 8.0?

[Ralf W. Grosse-Kunstleve]

--- "Martin v. Löwis" <martin at v.loewis.de> wrote:

> Well, yes: the areas are
> - memory management
> - stdio
> - locales
> for the C library; for the C++, I'm not so sure, but I think one of the
> areas is
> - static members of class templates, in particular in STL containers

Thanks for the insight! For Boost.Python users the situation is actually not
bad at all:

- there is not a single malloc() in the Boost.Python sources

- there is only one free(), which is specific to gcc; i.e. this code is not
seen by Visual C++.

- there is only one FILE* that is seen by Visual C++. It appears in the
signature of a function assigned to the tp_print slot. As far as I can tell
this is the only soft spot. I'll lobby for having the print function removed
since it is optional and both tp_str and tp_repr are defined anyway.

- nobody should be mixing C++ libraries compiled with different compilers on
any platform; it doesn't get much more dangerous than this. Since Python is
pure C "static members of class templates" should therefore be a non-issue.

This leaves only "stdio" and "locales" to be considered. We are strictly
avoiding both in C++ to maximize portability. I/O is intrinsically slow and
therefore there is no point in coding it in C++, especially since Python's I/O
is very fast anyway. I am not sure about locales because this is not very
interesting at all for scientific code development.

Under the assumption that the one tp_print function in the Boost.Python sources
is removed, I am arriving at the conclusion that it is more than pure luck that
all our tests work. People writing C++ extensions view the compiled layer as
low-level number-crunching back-end. It is quite natural not to find I/O and
use of locales in such code. And even if there is I/O, chances are it is done
via std::cout rather than a raw FILE* obtained from Python via difficult to
memorize incantations (I don't even know how to do it).

Cheers,
        Ralf



		
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