Is there a general consensus in the C++ community on when exceptions should be used? [closed]

Answer 1

As you can probably gather from the wealth of answers, there is certainly no consensus.

Semantically, exceptions and error provide the exact same functionality. Indeed they are identical in about all semantic aspects, and errors can be arbitrarily enriched much like exceptions (you don't have to use a simple code, you can use a real bundle of data!).

The only difference there is is their propagation methods:

• errors have to be passed down manually
• exceptions are propagated automatically

On the other hand:

• the possibility of an error is perfectly documented in the signature
• exceptions are silent on code inspection (read GotW #20: Code Complexity and cry) and hidden paths of execution make reasoning harder.

The very reason both solutions can appear clunky is simply that error checking is difficult. Indeed most of the code I am writing daily concerns error checking, whether technical or functional.

So what to do ?

Warning: demonstration ahead, jump over to the next section if you care only for an answer

I personally like to leverage the type system here. The typical example is the pointer-reference dichotomy: a pointer is like a reference that can be null (and reseated, but it does not matter here)

Therefore, instead of:

// Exceptions specifications are better not used in C++
// Those here are just to indicate the presence of exceptions
Object const& Container::search(Key const& key) const throw(NotFound);

I will tend to write:

Object const* Container::search(Key const& key) const;

Or better yet, using clever pointers:

Pointer