一条语句的困扰

typedef struct _ADAPT_FILTER_RSVD
{
   BOOLEAN     bFilterInitDone;

   //
   // More Per-Adapter Filter-Specific Members
   // ----------------------------------------
   // Probably would contain the filter data or a pointer to it. Possibly
   // filter statistics, state variables, whatever...
   //
   IPv4AddrStats        IPv4Stats;

   PIPv4BlockAddrArray  pIPv4BlockAddrArray;
   PARPHeader parp;
} ADAPT_FILTER_RSVD, *PADAPT_FILTER_RSVD;
C_ASSERT(sizeof(ADAPT_FILTER_RSVD) <= sizeof(((PADAPT)0)->FilterReserved));
请问语句C_ASSERT(sizeof(ADAPT_FILTER_RSVD) <= sizeof(((PADAPT)0)->FilterReserved))是什么意思？（其中PADAPT)是一个结构体指针，就像*PADAPT_FILTER_RSVD

就是要保证pAdapt中FilterReservered结构的大小>=sizeof(ADAPT_FILTER_RSVD)

谢谢版主啊