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Remove implicit cast operators on ResultValue<T>

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As it turned out to not provide a complete solution to the C++-API-change issue on logical-change of the C-API, we simply remove those implicit cast operators. That is, accessing the result and the value need to be explicit.
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asuessenbach
2020-07-20 13:48:03 +02:00
committed by Markus Tavenrath
parent 4cdc51ba0f
commit fba2516d9c
9 changed files with 206 additions and 134 deletions
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@@ -271,8 +271,7 @@ switch (result.result)
}
```
Note, that there are implicit cast operators in vk::ResultValue, which allow direct assignments of the returned value. That way, any success code is imlicitly ignored. If you want to make sure, you don't miss any such cases and correctly handle or explicitly ignore the success codes, define VULKAN_HPP_DISABLE_IMPLICIT_RESULT_VALUE_CAST before including vulkan.hpp.
As time passes, some vulkan functions might change, such that they start to support more result codes than `vk::Result::eSuccess` as a success code. That logical change would not be visible in the C-API, but in the C++-API, as such a function would now return a `vk::ResultValue<SomeType>` instead of just `SomeType`. If you have VULKAN_HPP_DISABLE_IMPLICIT_RESULT_VALUE_CAST defined, you suddenly get compiler errors, that force you to handle the changed logic.
As time passes, some vulkan functions might change, such that they start to support more result codes than `vk::Result::eSuccess` as a success code. That logical change would not be visible in the C-API, but in the C++-API, as such a function would now return a `vk::ResultValue<SomeType>` instead of just `SomeType`. In such (rare) cases, you would have to adjust your cpp-sources to reflect that API change.
If exception handling is disabled by defining `VULKAN_HPP_NO_EXCEPTIONS` the type of `ResultValue<SomeType>::type` is a struct holding a `vk::Result` and a `SomeType`. This struct supports unpacking the return values by using `std::tie`.