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Creating Shared Libraries Using Standard Naming Conventions

We can create a shared library using standard naming conventions as follows:

1. Create the shared library with real name libdemo.so.1.0.1 and soname libdemo.so.1.

   $ gcc -fPIC -g -c -Wall mod1.c mod2.c mod3.c
   $ gcc -shared -Wl,-soname,libdemo.so.1 -o libdemo.so.1.0.1 \
             mod1.o mod2.o mod3.o
   

2. Create symbolic links for the soname and linker name:

   $ ln -s libdemo.so.1.0.1 libdemo.so.1
   $ ln -s libdemo.so.1 libdemo.so
   $ ls -l libdemo.so* | cut -c 1-11,55-        # Verify the setup
   lrwxrwxrwx  libdemo.so -> libdemo.so.1
   lrwxrwxrwx  libdemo.so.1 -> libdemo.so.1.0.1
   -rwxr-xr-x  libdemo.so.1.0.1
   

3. Build executable using the linker name:

   $ gcc -g -Wall -o ./prog prog.c -L. -ldemo
   

4. Run the program as usual:

   $ LD_LIBRARY_PATH=. ./prog
   Called mod1-x1
   Called mod2-x2
   

(C) 2006, Michael Kerrisk