Andrew Haley wrote:
On 02/12/2010 05:53 AM, Marcus Clyne wrote:
I'm trying to compile a shared library, but am having problems.
I have one main binary, which will load one or several shared libraries
that all use a common set of functions. The functions common to all the
shared libraries I would like to store either in another shared library,
which the shared libraries themselves load, or (preferably) in the main
binary itself.
I'm using the following commands for compilation (simplified):
[1] gcc -Wall -fPIC -o shared.o -c file.c
[2] gcc -shared -o shared.so shared.o
The error message I'm getting is:
shared.o: relocation R_X86_64_PC32 against undefined symbol `my_func'
can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: ld returned 1 exit status
Where my_func is one of the common functions that I want to define
outside the shared library. I get this both when my_func is defined in
the main binary, and when it is defined in another shared object
(libcommon), and I add the following to [2]
-L/path/to/libcommon/dir -lcommon
That looks right. Maybe your libcommon.so doesn't have the right name?
Hard to say, you haven't provided enough details.
I've changed the name of 'libcommon.so' for the example, but it's
correct on the system. In any case, AFAIK, it shouldn't matter - the
error is appearing at compile-time (i.e. not load-time), so stage [2] is
failing (I forgot to make this clear).
I've successfully used the same procedure with other non-defined
functions which are in the main binary, and just included a header file
(as I did here).
Thanks,
Marcus.
