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我想使用winapi中的WriteFileEx将数据异步写入文件，但回调有问题。

我收到以下错误： “void (*) (DWORD dwErrorCode, DWORD dwNumberOfBytesTransfered, LPOVERLAPPED lpOverlapped)”类型的参数与“LPOVERLAPPED_COMPLETION_ROUTINE”类型的参数不兼容

我究竟做错了什么？

这是代码：

// Callback
void onWriteComplete(
        DWORD dwErrorCode,
        DWORD dwNumberOfBytesTransfered,
        LPOVERLAPPED lpOverlapped) {
    return;
}

BOOL writeToOutputFile(String ^outFileName, List<String ^> ^fileNames) {
    HANDLE hFile;
    char DataBuffer[] = "This is some test data to write to the file.";
    DWORD dwBytesToWrite = (DWORD) strlen(DataBuffer);
    DWORD dwBytesWritten = 0;
    BOOL bErrorFlag = FALSE;

    pin_ptr<const wchar_t> wFileName = PtrToStringChars(outFileName);

    hFile = CreateFile(
        wFileName,              // name of the write
        GENERIC_WRITE,          // open for writing
        0,                      // do not share
        NULL,                   // default security
        CREATE_NEW,             // create new file only
        FILE_FLAG_OVERLAPPED, 
        NULL);                  // no attr. template

    if (hFile == INVALID_HANDLE_VALUE) {
        return FALSE;
    }

    OVERLAPPED oOverlap;
    bErrorFlag = WriteFileEx(
        hFile,           // open file handle
        DataBuffer,      // start of data to write
        dwBytesToWrite,  // number of bytes to write
        &oOverlap,      // overlapped structure
        onWriteComplete),

    CloseHandle(hFile);
}
4

1 回答 1

4

您应该从仔细阅读文档开始。这部分特别重要：

OVERLAPPED 数据结构必须在写操作期间保持有效。它不应该是在写操作等待完成时可能超出范围的变量。

你没有满足这个要求，你需要紧急解决这个问题。

至于编译器错误，这很简单。您的回拨不符合要求。再次查阅其签名如下的文档：

VOID CALLBACK FileIOCompletionRoutine(
  _In_     DWORD dwErrorCode,
  _In_     DWORD dwNumberOfBytesTransfered,
  _Inout_  LPOVERLAPPED lpOverlapped
);

您省略CALLBACK了指定调用约定的。

于 2015-01-06T23:00:39.737 回答