What is the difference between static and dynamic libraries in linking?

Static libraries are linked at compile time, while dynamic libraries are linked at runtime.

Static libraries, also known as statically-linked libraries, are collections of object code that are linked with your program at compile time. When you compile your program, the linker takes the object code from the static library and includes it in the executable file. This means that once the program is compiled, it contains all the code it needs to run, making it larger but self-contained. The advantage of static libraries is that you can be sure that all the functions and resources your program needs are included in the executable, so it will run on any system without requiring additional libraries. However, this also means that if you update the library, you need to recompile and redistribute your program.

Dynamic libraries, on the other hand, are linked to your program at runtime. This means that the executable file doesn't contain the actual code from the library, but rather a reference to it. When you run the program, it loads the necessary library into memory. This makes the executable file smaller and allows multiple programs to share the same library, saving memory. The advantage of dynamic libraries is that you can update them without having to recompile or redistribute your program. However, this also means that if the library is not present on the system where the program is run, or if a different version of the library is present, the program may not work correctly.

In summary, the choice between static and dynamic libraries depends on your specific needs. If you want your program to be self-contained and not depend on the presence of certain libraries on the system, you might choose static libraries. If you want your program to be smaller, or if you want to be able to update the libraries without recompiling your program, you might choose dynamic libraries.