You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
On certain Linux distributions such as Ubuntu, the linker is invoked by default with --as-needed, which has an undesireable side effect when linking static libraries: it is bad at detecting required symbols, and the order of libraries on the command line become significant.
Right now, on my Ubuntu 12.10 system with a custom 32-bit version of Python, I get the following command output:
When linking a project with those flags, I get the following error:
/usr/bin/ld: /opt/pym32/lib/python2.7/config/libpython2.7.a(dynload_shlib.o): undefined reference to symbol 'dlopen@@GLIBC_2.1'
/usr/bin/ld: note: 'dlopen@@GLIBC_2.1' is defined in DSO /usr/lib/gcc/x86_64-linux-gnu/4.7/../../../i386-linux-gnu/libdl.so so try adding it to the linker command line
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../i386-linux-gnu/libdl.so: could not read symbols: Invalid operation
collect2: error: ld returned 1 exit status
To resolve the error, I moved -ldl and -lutil *AFTER* -lpython2.7, so the relevant chunk of my gcc command line looked like this:
I have no idea why --as-needed has such an unpleasant side effect when static libraries are being used, and it's arguable from my perspective that this behavior is the real bug. However it's equally likely that there's a good reason for that behavior, like it causes a slowdown during leap-years on Apple IIs or something. So here I am. python-config ought to respect the quirks of --as-needed when outputting its ldflags.
@max sorry about the delay in giving you a response. Can somebody please pick this up, I can't find on the experts list who to put on the nosy list for build issues.
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
Show more details
GitHub fields:
bugs.python.org fields:
The text was updated successfully, but these errors were encountered: