Using shared libraries vs a single executable

Question

My colleague claims that we should dissect our C++ application (C++, Linux) into shared libraries to improve code modularity, testability and reuse.

From my point of view it's a burden since the code we write does not need to be shared between applications on the same machine neither to be dynamically loaded or unloaded and we can simply link a monolithic executable application.

Furthermore, wrapping C++ classes with C-function interfaces IMHO makes it uglier.

I also think single-file application will be much more easy to upgrade remotely at a customer's site.

Should dynamic libraries be used when there is no need to share binary code between applications and no dynamic code loading?

Answer 1

I'd say that splitting code into shared libraries to improve without having any immediate goal in mind is a sign of a buzzwords-infested development environment. It is better to write code that can easily be split at some point.

But why would you need to wrap C++ classes into C-function interfaces, except for, maybe, for object creation?

Also, splitting into shared libraries here sounds like an interpreted language mindset. In compiled languages you try not to postpone till runtime what you can do at compile-time. Unnecessary dynamic linking is exactly the case.

Answer 2

Enforcing shared libraries ensures that libraries doesn't have circular dependencies. Using shared libraries often leads to faster linkage and link errors are discovered at an earlier stage than if there isn't any linking before the final application is linked. If you want to avoid shipping multiple files to customers you can consider linking the application dynamically in your development environment and statically when creating release builds.

EDIT: I don't really see a reason to why you need to wrap your C++ classes using C interfaces - this is done behind the scenes. On Linux you can use shared libraries without any special handling. On Windows, however, you would need to ___declspec(export) and ___declspec(import).