Vulkan-Hpp specific exception classes

[RippeR37]

What do you think about adding custom exception/error classes derived from one of the std::exception derived classes? Currently without special filtering developer can't really know if given exception (like std::system_error was thrown by Vulkan-Hpp or other piece of code and with that developers would be able to use natural exceptions "filtering" like:

try {
    // some Vulkan-Hpp code that can throw
    // with some normal code that can throw
} catch(const vk::error& vk_error) {
    // error from vulkan-related code
} catch(const std::exception& exception) {
    // error related to normal code / STL / etc.
}

Since exceptions already add some small overhead (mostly when fired), maybe we could also add hierarchy of exceptions representing some scenarios based on VkResult return value like

vk::error
    - vk::out_of_memory_error
        - vk::out_of_device_memory_error
        - vk::out_of_host_memory_error
    - vk::initialization_failed_error
    - vk::device_lost_error
    - ...

That way some errors might be handled right away and others might for example terminate application.
Worst case you could still catch them by std::exception or another STD-base-class.

[asuessenbach]

I think, this is a good idea. I will introduce them in the next couple of days.

[RippeR37]

I'm glad you liked it. I was thinking on how this should be implemented because standard exception classes doesn't inherit virtually, so we can't simply make:

vk::Error : std::exception
vk::SystemError : Error, std::system_error
vk::OutOfDeviceMemoryError : SystemError

and I've came up with couple ideas but none were perfect. Above implementation tries to:

• achieve backwards compatibility with existing code (exceptions inherit from std::logic_error or std::system_error)
• not double-inherit anything
• allow for grouping of Vulkan-Hpp exceptions and catch only them
• use existing STL exceptions like std::logic_error and std::system_error so that systems that work with them can be used here too
• expose some API to get exception message in base Vulkan-Hpp exception class

It's not perfect but without virtual inheritance between STL exceptions I think we can't do better.

P.S. I haven't updated vulkan.hpp there because for some reasons rebuilding it on my system changes each line, even without any changes...

[asuessenbach]

Regarding the changes on every line: this is probably due to a different end-of-line setting on your end. We're using CR/LF (Windows-style).

[asuessenbach]

Resolved with pull-request #99.