What are the different levels of exception safety in C++?

What are the different levels of exception safety in C++?

In C++, exception safety levels describe how a function behaves when an exception is thrown. There are three main levels: basic guarantee, strong guarantee, and no-throw guarantee.

Can you explain the basic guarantee?

The basic guarantee ensures that if an exception is thrown, the program remains in a valid state. It may leave some resources in an inconsistent state, but it won't cause a crash.

What about the strong guarantee?

The strong guarantee ensures that if an exception is thrown, the state of the program is unchanged. It means that operations can be rolled back, providing a safe fallback.

And the no-throw guarantee?

The no-throw guarantee means that a function will not throw any exceptions. This is crucial for certain operations where exceptions would disrupt the program's flow.