[jesse__]

It's remarkable to me how many codebases ban exceptions and yet, somehow, people still insist they're good.

[BeetleB]

> Our advice against using exceptions is not predicated on philosophical or moral grounds, but practical ones. ... Things would probably be different if we had to do it all over again from scratch.

They are clearly not against them per se. It simply wasn't practical for them to include it into their codebase.

And I think a lot of the cons of exceptions are handled in languages like F#, etc. If f calls g which calls h, and h throws an exception, the compiler will require you to deal with it somehow in g (either handle or explicitly propagate).

[jesse__]

My issue with exceptions is also practical. If they didn't introduce significant stability issues, I'd have no problem. As it stands, it's impossible to write robust software that makes use of C++ exceptions.

> the compiler will require you to deal with it somehow in g

I agree, this is the sensible solution.

[jandrewrogers]

In low-level systems software, which is a primary use case for C++, exceptions can introduce nasty edge cases that are difficult to detect and reason about. The benefits are too small to justify the costs to reliability, robustness, and maintainability.

Exceptions in high-level languages avoid many of these issues by virtue of being much further away from the metal. It is a mis-feature for a systems language. C++ was originally used for a lot of high-level application code where exceptions might make sense that you would never use C++ for today.

[jayd16]

Is this correct? I don't know F# but I thought it had unchecked exceptions. How does it handle using C# libs that throw unchecked exceptions?

[heyitsdaad]

The “pros” list is exceptionally weak. This was clearly written by someone who doesn’t like exceptions. Can’t blame them.

[azov]

Most codebases that ban exceptions do it because they parrot Google.

Google’s reasons for banning exceptions are historical, not technical. Sadly, this decision got enshrined in Google C++ Style Guide. The guide is otherwise pretty decent and is used by a lot of projects, but this particular part is IMO a disservice to the larger C++ ecosystem.

[alextingle]

I agree. I've worked on large C++ code bases that use exceptions, and they've never caused us any real problems.

[ryandrake]

I think reasonable people can disagree about whether C++ exceptions are "good" or not.

There are things you can't do easily in C++ without using exceptions, like handling errors that happen in a constructor and handling when `new` cannot alloc memory. Plus, a lot of the standard library relies on exceptions. And of course there's the stylistic argument of clearly separating error-handling from the happy-path logic.

I won't argue that it's popular to ban them, though. And often for good reasons.

[canucker2016]

For exception-less C++, you'd declare an operator new() that doesn't throw exceptions and just returns NULL on allocation failure along with a simple constructor and a followup explicitly-called init() method that does the real work which might fail and returns an error value on failure.

[tester756]

They're good for exceptional situations where foundamental, core assumptions are broken for some reason.

In such scenario there's no error recovery, software is expected to shutdown and raise loud error.

[jesse__]

If you're planning on shutting down, what's the fundamental difference between throwing an exception, vs simply complaining loudly and calling exit() ..?

[spacechild1]

> They're good for exceptional situations where foundamental, core assumptions are broken for some reason.

No, that's what assertions or contracts are for.

Most exceptions are supposed to be handled. The alternative to exceptions in C++ are error codes and `std::expected::. They are used for errors that are expected to happen (even if they may be exceptional). You just shouldn't use exceptions for control flow. (I'm looking at you, Python :)

[ljm]

Yet, if you can only explain an exception using the word ‘exception’ you’re not making any head way.

I like the idea of an exception as a way to blow out of the current context in order for something else to catch it and handle in a generic manner. I don’t like the idea of an exception to hide errors or for conditional logic because you have to know what is handling it all. Much easier to handle it there and then, or use a type safe equivalent (like a maybe or either monad) or just blow that shit up as soon as you can’t recover from the unexpected.

[dijit]

I use asserts for this purpose.

[wvenable]

Looking at this ban list, they've removed everything from C++ that makes it fun. Come on people, who doesn't love a little std::function?!?

On banning exceptions:"Things would probably be different if we had to do it all over again from scratch."

https://google.github.io/styleguide/cppguide.html#Exceptions

[pkasting]

We have base::Callback for when you'd reach for std::function, which provides superior safety.