链接到AIX上的共享库

Question

I'm trying to link against a shared library (apr) on AIX 5.3 using gcc/libtool.

The output from the compiler is as follows (with some irrelevant flags removed for the sake of simplicity):

libtool: link: gcc  -o test test.o  -L/opt/freeware/lib -lapr-1 -lpthread -Wl,-blibpath:/opt/freeware lib:/usr/lib:/lib 

Then I checked what shared libs the resulting binary uses:

$ ldd test 
test needs:
     /usr/lib/libc.a(shr.o)
     /usr/lib/libpthread.a(shr_xpg5.o)
     /unix
     /usr/lib/libcrypt.a(shr.o)
     /usr/lib/libpthreads.a(shr_comm.o)

Notice that 'libapr-1' is missing here, though the symbols are there in the binary (verified with nm), which suggests that it is linked in statically.

This wouldn't be such a big problem for simple programs. Unfortunately my code in question uses dynamically loadable modules. The main program calls apr_initialize which sets a static variable 'apr_pools_initialized' inside the library. The loadable modules then try to use apr_pool_create which first check whether the initialization has been performed. Since they have their own statically linked apr, the static variable 'apr_pools_initialized' is not at the same memory location what the main program initialized. This makes the statically linked binary non-functional.

The apr library is installed using a precompiled binary rpm (apr and apr-devel). The relevant library files are there:

# rpm -ql apr|grep \\.so$
/opt/freeware/lib/libapr-1.so
/opt/freeware/lib64/libapr-1.so
/usr/lib/libapr-1.so

# rpm -ql apr-devel|grep \\.a$
/opt/freeware/lib/libapr-1.a
/opt/freeware/lib64/libapr-1.a
/usr/lib/libapr-1.a
/usr/lib64/libapr-1.a
/usr/lib64/libapr-1.so

I tried to remove the '.a' files hoping that the linker would have no choice but to use the '.so' and link it dynamically, unfortunately AIX is different and this does not work. Regarding this topic I have found this answer and another libtool question which give some insight.

The question is: How can I link this to my binary dynamically?

Answer 1

Actually the links referenced contained the solution to this problem, which is:

-Wl,-brtl

Adding these LDFLAGS solved the linking problem.