[Python-Dev] please consider changing --enable-unicode default to ucs4 (original) (raw)

M.-A. Lemburg mal at egenix.com
Mon Sep 28 10:36:07 CEST 2009

M.-A. Lemburg wrote:

Also note that Python will complain loudly when you try to load a UCS2 extension in a UCS4 build and vice-versa. We've made sure that any extension using the Python Unicode C API has to be built for the same UCS version of Python. This is done by using different names for the C APIs at the C level.

These are not isolated incidents. The following google searches suggest that a number of people spend time trying to figure out why Python extension modules fail on their linux systems:

http://www.google.com/search?q=PyUnicodeUCS4FromUnicode+undefined+symbol http://www.google.com/search?q=+PyUnicodeUCS2FromUnicode+undefined+symbol http://www.google.com/search?q=PyUnicodeUCS2AsDefaultEncodedString+undefined+symbol Perhaps we should add a FAQ entry for these linker errors (which are caused by the mentioned C API changes to prevent mixing UCS version) ?!

There already is one:

http://www.python.org/doc/faq/extending/#when-importing-module-x-why-do-i-get-undefined-symbol-pyunicodeucs2

I wonder why it doesn't show up in the Google searches.

Here's a quick way to determine you Python Unicode build type:

python -c "import sys;print((sys.maxunicode<66000)and'UCS2'or'UCS4')" Perhaps we should include this info as well as an 32/64-bit indicator and the processor type in the Python startup line: # python Python 2.6 (r26:66714, Feb 3 2009, 20:49:49, UCS4, 64-bit, x8664) [GCC 4.3.2 [gcc-43-branch revision 141291]] on linux2 Type "help", "copyright", "credits" or "license" for more information. This would help users find the right binaries to install as extension.

Regards,

Marc-Andre Lemburg eGenix.com

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