Raspicam C++ API mmal linking

Question

I have installed the raspicam API as instructed here: http://www.uco.es/investiga/grupos/ava/node/40

It appears to be installed correctly.

When I compile any programs linking libmmal I get the errors:
/usr/bin/ld: cannot find -lmmal
/usr/bin/ld: cannot find -lmmal_core
/usr/bin/ld: cannot find -lmmal_util

I have tried updating the pi and reinstalling the API but I just can't get it to compile.

Answer 1

Try ldconfig -p | grep libmmal. On raspbian you should get:

    libmmal_vc_client.so (libc6,hard-float) => /opt/vc/lib/libmmal_vc_client.so
    libmmal_util.so (libc6,hard-float) => /opt/vc/lib/libmmal_util.so
    libmmal_core.so (libc6,hard-float) => /opt/vc/lib/libmmal_core.so
    libmmal_components.so (libc6,hard-float) => /opt/vc/lib/libmmal_components.so
    libmmal.so (libc6,hard-float) => /opt/vc/lib/libmmal.so

If not, add to your question the contents of the few short files in /etc/ld.so.conf.d. If you are not using raspbian, you should give your OS.

---

This means the relevant libraries are available on the system and if you build an executable linking them, there should not be a problem. However, there may be a problem building the executable; in this case it seems when gcc invokes the linker, /opt/vc/lib is not in its path even though it is in the runtime loader path (they are not quite the same). If you use gcc -v, you'll see there are some non-standard paths being used as options (e.g., /usr/lib/gcc/arm-linux-gnueabihf), but not that one. However, you can specify it yourself:

gcc test.c -L/opt/vc/lib -lmmal

Should work. You can also:

export LIBRARY_PATH=/opt/vc/lib

This variable is probably not predefined but you'll see those other paths added to it in gcc -v output. Note it is not the same as LD_LIBRARY_PATH, which is used by the runtime loader.