异步机制 - BindIoCompletionCallback

直接上代码

VOID CALLBACK test_io_completion_routine(

DWORD dwErrorCode,

DWORD dwNumberOfBytesTransfered,

LPOVERLAPPED lpOverlapped

)

{

printf("dwErrorCode %d, dwNumberOfBytesTransfered %d\n", dwErrorCode, dwNumberOfBytesTransfered);

printf("%s\n", (char*)(lpOverlapped + 1));

free(lpOverlapped);

}

BOOL

queue_read_req(

HANDLE hFile,

DWORD nNumberOfBytesToRead,

DWORD Offset)

{

BOOL bResult = FALSE;

OVERLAPPED* olv = (OVERLAPPED* )malloc(sizeof(OVERLAPPED) + nNumberOfBytesToRead);

if(olv)

{

DWORD nBytesRead = 0;

ZeroMemory(olv, sizeof(OVERLAPPED) + nNumberOfBytesToRead);

olv->Offset = Offset;

bResult = ReadFile(hFile, (void*)(olv + 1), nNumberOfBytesToRead, &nBytesRead, olv) ;

if (!bResult)

{

DWORD dwError = 0;

switch (dwError = GetLastError())

{

case ERROR_HANDLE_EOF:

free(olv);

break;

case ERROR_IO_PENDING:

break;

default:

break;

}

}

}

return bResult;

}

void test_io_port()

{

LPCWSTR FileTest = L"C:\\NTDLL.txt";

HANDLE hFile = CreateFileW(FileTest,               // file to open

GENERIC_READ,          // open for reading

FILE_SHARE_READ,       // share for reading

NULL,                  // default security

OPEN_EXISTING,         // existing file only

FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, // normal file

NULL); // no attr. template

if(hFile != INVALID_HANDLE_VALUE)

{

BindIoCompletionCallback(hFile, test_io_completion_routine, 0);

for(int i = 0; i < 5; i++)

{

queue_read_req(hFile, 1024, i*1024 );

}

Sleep(5000);

CloseHandle(hFile);

}

}