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std::process::exit does not call Drop traits (at least the last time I tried -- maybe I am doing it wrong?). So for example, if you're relying on Drop to clean

std::process::exit does not call Drop traits (at least the last time I tried -- maybe I am doing it wrong?). So for example, if you're relying on Drop to clean up temporary files in the system, that will not happen. Providing no method to call destructors AND exit non-zero feels like a bug or missing feature. EDIT: to expand on this: a suggested workaround is to only call std::process::exit at the very end of the main function. But consider stuff like "env_logger::init". What about that? Ok, that doesn't use Drop and if it did you could put it into it's own scope I guess - so there are workarounds - but it in my opinion that gets pretty ugly. Comparing to c++, std::process::exit or panic! is like abort(), but what I want is a "return 1" from main.

steveklabnik 8y ago
You're not wrong. The issue is, it's hard to make a good API for this; anything else is basically dealing with global state, and so you don't have a guarantee that something else doesn't re-set it to something else while unwinding is happening, etc. I do have one more thing to say on this, but it fits better in a reply elsewhere in the thread :) panic! does return a non-zero exit code, but isn't really designed for good end-user output.
- rabidferret 8y ago
  If you don't care about the specific error code as long as it's non-zero, just returning `Result<(), impl Debug>` does what you want on stable now, right?
  - steveklabnik 8y ago
    That's true, but then you have to juggle Results as your return type everywhere. It's probably a good idea overall, but some people don't want to do that. And yes, you don't get to pick the code. Yet!
rabidferret 8y ago
Calling `std::process:exit(1)` at the end of main is identical to `return 1`. I'm not sure what your point is with `env_logger::init`. It sounds like you think destructors are run on static items? They aren't. In fact, until very recently you weren't even allowed to have destructors on consts/statics
- firebacon 8y ago
  > I'm not sure what your point is with `env_logger::init` That most of my programs have some global (i.e. "for the runtime of the program") stuff that is setup at the beginning of main. And that some of that might want to Drop when the program exits, for example to delete a temporary directory. Now, if I want to return a non-zero exit code I can not do so while still getting all this global stuff destructed correctly (or use a workaround like having a wrapper-main). > Calling `std::process:exit(1)` at the end of main is identical to `return 1`. The thing is that it is actually not the same with respect to destructors -- the documentation explicitly calls that out. See also the C++ comparison in my other comment.
  - rabidferret 8y ago
    Ah, I see. You're wanting to have destructors run on local variables assigned in `main`.

steveklabnik 8y ago

You're not wrong. The issue is, it's hard to make a good API for this; anything else is basically dealing with global state, and so you don't have a guarantee that something else doesn't re-set it to something else while unwinding is happening, etc. I do have one more thing to say on this, but it fits better in a reply elsewhere in the thread :) panic! does return a non-zero exit code, but isn't really designed for good end-user output.

rabidferret 8y ago
If you don't care about the specific error code as long as it's non-zero, just returning `Result<(), impl Debug>` does what you want on stable now, right?
- steveklabnik 8y ago
  That's true, but then you have to juggle Results as your return type everywhere. It's probably a good idea overall, but some people don't want to do that. And yes, you don't get to pick the code. Yet!

rabidferret 8y ago

Calling `std::process:exit(1)` at the end of main is identical to `return 1`. I'm not sure what your point is with `env_logger::init`. It sounds like you think destructors are run on static items? They aren't. In fact, until very recently you weren't even allowed to have destructors on consts/statics

firebacon 8y ago
> I'm not sure what your point is with `env_logger::init` That most of my programs have some global (i.e. "for the runtime of the program") stuff that is setup at the beginning of main. And that some of that might want to Drop when the program exits, for example to delete a temporary directory. Now, if I want to return a non-zero exit code I can not do so while still getting all this global stuff destructed correctly (or use a workaround like having a wrapper-main). > Calling `std::process:exit(1)` at the end of main is identical to `return 1`. The thing is that it is actually not the same with respect to destructors -- the documentation explicitly calls that out. See also the C++ comparison in my other comment.
- rabidferret 8y ago
  Ah, I see. You're wanting to have destructors run on local variables assigned in `main`.