static_library

Static Library

We would like to create a link library containing the object code of the sum() and mul() functions written inside mymath.c source file, which can be called from different C programs.

1. We produce the file object mymath.o:

$ gcc -c mymath.c

2. Create static link library from mymath.o:

$ ar rcs libmylib.a mymath.o

3. Static compile main.c with mylib.a as link library. Note that -L specifies the "current directory" library path, -l specifies the library, without the prefix and the suffix:

$ gcc -static main.c -L. –lmylib

4. Now executable is ready to be executed:

$ ./a.out

Naming conventions

Dynamic library has the prefix lib and the suffix .a

Display contents of the archive

$ ar -t libmylib.a
mymath.o

Converting static library to dynamic library

$ ar -x libmylib.a

The full collection of the object files is extracted from static library, now we can build shared library.