一个问题，大家帮忙

我定义了一个结构
typedef struct _WRITE_CMD
{
unsigned char cmd_id;
unsigned long start_lba;
unsigned long write_len;
unsigned char sector[512];

} WRITE_CMD, *PWRITE_CMD;
但由于想把sector定义的大一点，想用ExAllocatePool分配那么结构是不是应该定义为typedef struct _WRITE_CMD
{
unsigned char cmd_id;
unsigned long start_lba;
unsigned long write_len;
unsigned char sector；

} WRITE_CMD, *PWRITE_CMD;

我这样分配了一下
dBufferSize = sizeof (unsigned char) + sizeof(unsigned long) * 2+ sizeof(unsigned char) *56*1024;
        
        write_cmd = (PWRITE_CMD)ExAllocatePool (
                                             NonPagedPool,
                                             dBufferSize );

write_cmd->cmd_id = 0x2a;
write_cmd->start_lba = htonl(StartLBA);
write_cmd->write_len = htonl(left);

RtlCopyMemory((void*)write_cmd->sector, (UCHAR *)(pSrb->DataBuffer), left);
最后这一句好像有问题，老是兰频，大家帮忙

定义成这样
{
unsigned char cmd_id;
unsigned long start_lba;
unsigned long write_len;
unsigned char sector[1]；

} WRITE_CMD, *PWRITE_CMD;

对,应该象楼上说的那样定义,这样可以不受长度了限制,而且直接可以用结构成员变量访问你的不定长成员变量sector.

我这样分配以后，通过write_cmd->cmd_id 得到的值怎么不正确啊

结构如下定义
typedef struct _WRITE_CMD
{
unsigned long cmd_id;
unsigned long start_lba;
unsigned long write_len;
unsigned char sector[1];

} WRITE_CMD, *PWRITE_CMD;

通过如下方式分配


ULONG dBufferSize;  
dBufferSize =  sizeof(unsigned long) * 3+ sizeof(unsigned char) *left;
        
        write_cmd = (PWRITE_CMD)ExAllocatePool (
                                             NonPagedPool,
                                             dBufferSize+1);
                                            
write_cmd->cmd_id = htonl(42);

write_cmd->start_lba = htonl(StartLBA);
write_cmd->write_len = htonl(left);

RtlCopyMemory((void*)write_cmd->sector, (UCHAR *)(pSrb->DataBuffer), left);

len = sizeof(write_cmd);
dStatus = TdiSendDatagram ( // send datagram
pTdiTransportObject, // to transport
MY_PORT, // port
dTdiRemoteAddress, // address
&write_cmd, // data
len ); // size
if ( !NT_SUCCESS ( dStatus ) )
DbgPrint ( \"ERROR: writing sending %X\\n\", dStatus );
else
DbgPrint ( \"writing send success\\n\" );
发到Server端以后
通过
iRtn = recvfrom( s, (char *)buf, sizeof(buf), 0, (struct sockaddr *)&from, &len);接收数据
后，发现buf[0]不是42，不知道啥原因。