程序代码：

string GetErrorMsg()
{
    DWORD dwErrorId = GetLastError();
    LPVOID lpMsgBuf;

    FormatMessage(
        FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL,
        dwErrorId,
        0,
        (LPSTR) &lpMsgBuf,
        0,
        NULL);

    string strErrorMsg = (char*)lpMsgBuf;
    LocalFree(lpMsgBuf);

    return strErrorMsg;
}