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问题描述
我认为retval用于向用户返回值并输入。但是我无法区分out和retval。我已经阅读了几篇文章，但却无法理解。任何人都可以帮我解释一下吗？
I think retval is used to return a value to the user & in is for input. But i cant differentiate between out & retval. I have gone through several articles but not able to understand it. can anyone explain it for me?
推荐答案
HRESULT Test([out, retval] int *rv) { ... }将成为
would become
int Test() { ... }并抛出一个出现错误时的异常（负HRESULT）。
and throw an exception in case of an error (negative HRESULT).
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