为何 RasEnumConnections 函数总是返回错误 ERROR_INVALID_SIZE

[fangqing0827]

以下代码来自于msdn ：



#include "windows.h"
#include "Ras.h"
#include "raserror.h"
#pragma comment(lib,"Rasapi32.lib")
void main()
{
DWORD dwCb = sizeof(RASCONN);
DWORD dwErr = ERROR_SUCCESS;
DWORD dwRetries = 5;
DWORD dwConnections = 0;
RASCONN* lpRasConn = NULL;

while (dwRetries--)
{
if (NULL != lpRasConn)
{
HeapFree(GetProcessHeap(), 0, lpRasConn);
lpRasConn = NULL;
}

lpRasConn =(RASCONN*) HeapAlloc(GetProcessHeap(), 0, dwCb);
if (NULL == lpRasConn)
{
dwErr = ERROR_NOT_ENOUGH_MEMORY;
break;
}

lpRasConn->dwSize = sizeof(RASCONN);

dwErr = RasEnumConnections(
lpRasConn,
&dwCb,
&dwConnections);
if (ERROR_BUFFER_TOO_SMALL != dwErr)
{
//在这里下断点，RasEnumConnections 总是返回 ERROR_INVALID_SIZE，不解
break;
}
}

if (ERROR_SUCCESS == dwErr)
{
DWORD i;

printf("The following RAS connections are currently active\n\n");
for (i = 0; i < dwConnections; i++)
{
printf("%s\n", lpRasConn[i].szEntryName);
}
}
else
{
printf("RasEnumConnections failed: Error = %d\n", dwErr);
}

if (NULL != lpRasConn)
{
HeapFree(GetProcessHeap(), 0, lpRasConn);
lpRasConn = NULL;
}
}