On Sun, Feb 7, 2016 at 4:38 AM, Antoine Pitrou <solip...@pitrou.net> wrote: > On Sun, 7 Feb 2016 00:25:57 -0800 > "Robert T. McGibbon" <rmcgi...@gmail.com> wrote: >> > What are Debian/Ubuntu doing in distutils so that extensions don't link >> to libpython by default? >> >> I don't know exactly, but one way to reproduce this is simply to build the >> interpreter without `--enable-shared`. > > See https://bugs.python.org/issue21536. It would be nice if you could > lobby for this issue to be resolved... (though that would only be for > 3.6, presumably)
Just to unpack from that issue - and quoting a nice summary by you (Antoine): "... the -l flag was added in #832799, for a rather complicated case where the interpreter is linked with a library dlopened by an embedding application (I suppose for some kind of plugin system)." Following the link to https://bugs.python.org/issue832799 - the `-l` flag (and therefore the dependency on libpython was added at Python 2.3 for the case where an executable A dlopens a library B.so . B.so has an embedded Python interpreter and is linked to libpython. However, when the embedded Python interpreter in B.so loads an extension module mymodule.so , mymodule.so does not inherit a namespace with the libpython symbols already loaded. See https://bugs.python.org/msg18810 . One option we have then is to remove all DT_NEEDED references to libpython in manylinux wheels. We get instant compatibility for bare Debian / Ubuntu Python installs, at the cost of causing some puzzling crash for the case of: dlopened library with embedded Python interpreter where the embedded Python interpreter imports a manylinux wheel. On the other hand, presumably this same crash will occur for nearly all Debian-packaged Python extension modules (if it is true that they do not specify a libpython dependency) - so it seems unlikely that this is a common problem. Cheers, Matthew _______________________________________________ Distutils-SIG maillist - Distutils-SIG@python.org https://mail.python.org/mailman/listinfo/distutils-sig
