Problems loading a lib, using mysql

[J Andersen]

On linux: I am creating a STAF service, which is basically a shared library that is loaded manually (with dlopen or similar). The library compiles and links with no errors, but won't load:

# STAFProc
Caught STAFException
Name : STAFException
Location : /opt/dev/autobuild/build/src/staf/stafif/STAFDynamicLibraryInlImpl.cpp(29)
Text : STAFDynamicLibraryOpen: /usr/local/staf/lib/libinfares.so: undefined symbol: _ZN3sql5mysql25get_mysql_driver_instanceEv
Error code: 10
Error reading config file

However, ldd says:

# ldd /usr/local/staf/lib/libinfares.so
libpthread.so.0 => /lib/libpthread.so.0 (0x00002b2fcad12000)
libcrypt.so.1 => /lib/libcrypt.so.1 (0x00002b2fcae28000)
libdl.so.2 => /lib/libdl.so.2 (0x00002b2fcaf5c000)
libSTAF.so => not found
libmysqlclient_r.so.15 => /usr/lib/libmysqlclient_r.so.15 (0x00002b2fcb060000)
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00002b2fcb362000)
libm.so.6 => /lib/libm.so.6 (0x00002b2fcb560000)
libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x00002b2fcb6e3000)
libc.so.6 => /lib/libc.so.6 (0x00002b2fcb7f0000)
/lib64/ld-linux-x86-64.so.2 (0x0000555555554000)
libnsl.so.1 => /lib/libnsl.so.1 (0x00002b2fcba2d000)
libz.so.1 => /usr/lib/libz.so.1 (0x00002b2fcbb45000)

So it clearly finds libmysqlclient_r.so. What is wrong here? Is it the wrong library I link against?