2.3.2. Creating dynamic libraries with the GCC

Procedure

1. Change to the directory with library sources.

2. Compile each source file to an object file with the Position independent code option -fPIC:

   $ gcc ... -c -fPIC some_file.c ...

   The object files have the same file names as the original source code files, but their extension is .o.

3. Link the shared library from the object files:

   $ gcc -shared -o libfoo.so.x.y -Wl,-soname,libfoo.so.x some_file.o ...

   The used major version number is X and minor version number Y.

4. Copy the libfoo.so.x.y file to an appropriate location, where the system’s dynamic linker can find it. On Red Hat Enterprise Linux, the directory for libraries is /usr/lib64:

   # cp libfoo.so.x.y /usr/lib64

   Note that you need root permissions to manipulate files in this directory.

5. Create the symlink for the soname:

   # ln -s libfoo.so.x.y libfoo.so.x

6. Create the symlink for the linker name:

   # ln -s libfoo.so.x libfoo.so