今天用了一下RasEnumConnections函数，发现MSDN上的例子是错误的。
MSDN上RasEnumConnections的文档是这么说的：
[U]复制代码[/U] 代码如下:
To determine the required buffer size, call RasEnumConnections with lprasconn set to NULL. The variable pointed to by lpcb should be set to zero. The function will return the required buffer size in lpcb and an error code of ERROR_BUFFER_TOO_SMALL.
MSDN上提供的示例代码也是这么写的：
[U]复制代码[/U] 代码如下:
DWORD __cdecl wmain(){
DWORD dwCb = 0;
DWORD dwRet = ERROR_SUCCESS;
DWORD dwConnections = 0;
LPRASCONN lpRasConn = NULL;