C Dynamic Libraries: Create & Use Guide
To create a dynamic library (also known as a shared library), typically the following steps need to be followed:
- The source code file for a library, typically with a .c extension, contains the implementation code for the functions and data structures needed in the library.
- Compile the source code file and link it as a shared library. When compiling, use the -shared option to link the generated object files as a shared library. For example, compile the mylib.c file to generate the shared library libmylib.so using the following command:
gcc -shared -o libmylib.so mylib.c
- Place the generated shared library files in the system path so that other programs can access them. Typically, you can copy the shared library files to the /usr/lib or /usr/local/lib directories.
- Include the library’s header file and link the shared library in the program where the library is needed. For example, write a program main.c that uses the libmylib.so library and compile it with the following command:
gcc -o main main.c -lmylib
The -lmylib option tells the compiler to link the shared library named libmylib.so.
- Run the generated executable file, which will dynamically load shared libraries and call functions within them to achieve the desired functionality.
In general, the process of creating and using a dynamic library involves writing the library’s source code, compiling it to generate a shared library, placing the shared library in the system path, and writing a program that uses the library and links to the shared library.