[Python-Dev] GCC version compatibility (original) (raw)

David Abrahams dave at boost-consulting.com
Sun Jul 10 15:38:35 CEST 2005

Christoph Ludwig <cludwig at cdc.informatik.tu-darmstadt.de> writes:

--with-cxx=: If you plan to use C++ extension modules, then on some platform you need to compile python's main() function with the C++ compiler. With this option, make will use to compile main() and to link the python executable. It is likely that the resulting executable depends on the C++ runtime library of .

Note there are platforms that do not require you to build Python with a C++ compiler in order to use C++ extension modules. E.g., x86 Linux with ELF shared binaries and GCC 3.x, 4.x is such a platform. We recommend that you configure Python --without-cxx on those platforms to avoid unnecessary dependencies.

I don't think that's strong enough. What happens is that dynamically loaded Python extension modules built with other, ABI-compatible versions of G++ may crash.

If you need to compile main() with , but your platform does not require that you also link the python executable with (e.g., ), then set LINKCC='$(PURIFY) $(CC)' prior to calling make. Then the python executable will not depend on the C++ runtime library of .

Are we sure we have an actual use case for the above? Doesn't --without-cxx cover all the actual cases we know about?

BTW, I'd also change the short explanation output by `configure --help'. Something like:

ACHELPSTRING(--with-cxx=, use to compile and link main()) In Python 2.4.1, the help message says "enable C++ support". That made me use this option even though it turned out it is not necessary on my platform.

Your suggestion is simple and powerful; I like it!

-- Dave Abrahams Boost Consulting www.boost-consulting.com

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