OVERLAPPED结构体就没有预留用户自定义参数，通过GetQueuedCompletionStatus得到OVERLAPPED*之后，怎么得到与其对应的用户参数？举个例子
HANDLE hCompletionPort = NULL;
char buf1[4 * 1024];
…………
char bufn[4 * 1024];
void f1()
{
hCompletionPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0);
hFile1 = CreateFile…………WithOverlappedFlag
hFile2 …………
…………
hFilen …………
CreateIoCompletionPort(hCompletionPort, hFile1, 0, 0);
CreateIoCompletionPort(hCompletionPort, hFile2, 0, 0);
…………
CreateIoCompletionPort(hCompletionPort, hFilen, 0, 0);
OVERLAPPED* op1 = new OVERLAPPED;
ReadFileEx(hFile1, buf1, sizeof(buf1), op1, NULL);
OVERLAPPED* op2 = new OVERLAPPED;
ReadFileEx(hFile2, buf2, sizeof(buf2), op2, NULL);
…………
OVERLAPPED* op3 = new OVERLAPPED;
ReadFileEx(hFilen, bufn, sizeof(bufn), op3, NULL);
}
void f2()
{
DWORD dwNumberOfBytes = 0;
ULONG_PTR key = 0;
OVERLAPPED* op = NULL;
GetQueuedCompletionStatus(hCompletionPort, &dwNumberOfBytes, &key, &op, INFINITE);//1
}
注释1（//1）处得到op，但是此op是读的哪个文件呢？
