Dealing with the locations of libraries

Question

What can you do when your linux system "can't find" dynamically linked libraries that are indeed installed in their correct locations?

Case in point, I'm trying to run a program called 'ucanvcam':

oliver@human ~/installed/ucanvcam-0.1.6/bin $ ./ucanvcam
./ucanvcam: error while loading shared libraries: libgd.so.2: cannot open shared object file: No such file or directory

oliver@human ~/installed/ucanvcam-0.1.6/bin $ locate libgd.so.2
/usr/lib64/libgd.so.2.0.0
/usr/lib64/libgd.so.2

oliver@human ~/installed/ucanvcam-0.1.6/bin $ ldd ./ucanvcam
    linux-gate.so.1 =>  (0xf7706000)
    [...]
    libgd.so.2 => not found
    [...]
    librt.so.1 => /lib32/librt.so.1 (0xf6b1e000)

How can I tell it to look for libgd.so.2 in /usr/lib64? And more importantly, why isn't it looking there, and where is it looking?

Thanks,
Mala

Answer 1

The manual page for ld.so will help you with this. In particular the important things to look at are probably the contents of your shell variable LD_LIBRARY_PATH and the file /etc/ld.so.conf.