Linux Program can't find Shared Library at run-time

Question

I'm trying to compile a linux program, id3v2, and it says it is can't find the appropriate library:

id3v2: error while loading shared libraries: libid3-3.8.so.3: cannot open shared object file: No such file or directory

I'm guessing that this is the part that pulls in the lidid3 library?

The file DOES exist, however, what they are looking for is actually a symbolic link to:

"ibid3-3.8.so.3.0.0"

I'm wondering if it is an issue with it not being able to follow symbolic links? Perhaps I could manually change it to look for 0.0 if I knew where I was looking to change it.

I'm happy to clarify any details.

It looks like the includes are done in the following manner:

id3v2:  convert.o list.o id3v2.o genre.o
        ${CXX} ${LDFLAGS} -pedantic -Wall -g -o $@ $^ -lz -lid3

I was able to use Simon's advice to figure out that there were multiple spots where one might expect a library. I create a symbolic link where the program was linking to the ACTUAL file.

Thank you Simon!

Answer 1

Symlinks on libraries work fine, as long as the final target they trace to exists and is accessible.

You have built a dynamically-linked executable, that wishes to be linked against libid3-3.8.so.3 at execution time. This was likely linked during the build phase with something like -L/path/to/libid3/directory -lid3.

You have a few options to make libid3 available, in generally decreasing order of preference (since you didn't mention where the file was, I can only be general):

• Create a symlink to libid3* in a directory listed in /etc/ld.so.conf (or /lib or /usr/lib)
• Copy libid3* to a directory listed in /etc/ld.so.conf (or /lib or /usr/lib) (defaults)
• Add the directory containing libid3* to /etc/ld.so.conf
• Set LD_LIBRARY_PATH=/directory/path/to/libid3* before running your id3v2 executable.
• Recompile id3v2 statically. (It will work, but don't bother.)

After any of the first 3, rerun ldconfig so the linker cache is updated. (You can then run ldconfig -v to verify it's resolvable.)

Note those aren't steps, they're options. You only need to do 1 of them.

Glad you updated the title. #include directives have nothing to do with linking.

Answer 2

I got the same error you did, and after reading the solutions mentioned here, I resolved the problem (on Ubuntu 8) with:

sudo ln -s /usr/local/lib/libid3-3.8.so.3 /usr/lib/libid3-3.8.so.3

Answer 3

This solved the issue Just add /usr/local/lib to /etc/ld.so.conf (unless it's already in there; only put it once), then run ldconfig.