No problem http://www.freemoe.org/users/qwerty12/libcallnotify.so Well, for me, I knew what it was trying to open didn't exist and the rest of your code looked legit so I could only assume that fopen had returned NULL http://en.wikipedia.org/wiki/GNU_Libtool - I can't really explain it properly, but I guess it's a long and complicated script that makes libraries straight from C files. I have no idea how to invoke it on its own actually ; I use Autotools in my **** and the macros take care of that for me... Oh, I tested on the device