C++ 风格的指针转换为整数

Question

在 GetQueuedCompletionStatus() 的文档中, MSDN 说

This is done by specifying a valid event handle for the hEvent member of the OVERLAPPED structure, and setting its low-order bit.

假设事件是 HANDLE 类型，一个 void * 的类型定义，我如何使用 C++ 风格的转换来做到这一点？我不能直接将 |= 1 应用于指针，reinterpret_cast 只能在具有相同间接级别的类型之间进行转换，而 static_cast 也不起作用。这样做的 C++ 方法是什么，避免 C 风格的转换并使用 C++ 风格的转换为 size_t？我知道另一种方法是使用 union ，但这似乎比使用 C 风格的转换更难。

Answer 1

reinterpret_cast 是你需要的:

OVERLAPPED MyOverlapped;
// ...

MyOverlapped.hEvent = GetEvent();  // replace with whatever O/S call that is provided the event handle
ASSERT((reinterpret_cast<uintptr_t>(MyOverlapped.hEvent) & 0x1) == 0x0);  // if lsbit is a flag, then OS source of hEvent better NOT have it INITIALLY set!
reinterpret_cast<uintptr_t &>(MyOverlapped.hEvent) |= 0x1;
// ...
GetQueuedCompletionStatus(..., &MyOverlapped, ...);