结构成员对齐 – 使用16位和32位编译器的不同sizeof

typedef struct
{
    unsigned char   new_weld_status[2];   //a
    //char padding_1[2]; //hidden padding
    UINT32  new_weld_count;               //a
    UINT16  new_weld_fail_count;          //a
} NEW_PULSE_DATA;

以下对结构的重新定义完全避免了这个问题.

typedef struct
{
    UINT32  new_weld_count;               //a
    UINT16  new_weld_fail_count;          //a
    unsigned char   new_weld_status[2];   //a
} NEW_PULSE_DATA;
NEW_PULSE_DATA ex_PULSE_DATA;

然而,上述方法通常不是通过网络/通过消息传输来传输结构(ured)数据的方法.一种更常见且更好的方法是使用序列化/反序列化层(也称为编组)将结构放置在“线上”格式中.您当前的方法是将内存存储和寻址与通信格式混为一谈.

//you need to decide on the size of wire format data,//Both ends of the protocol must agree on these sizes,#define new_weld_count_SZ sizeof(ex_PULSE_DATA.new_weld_count)
#define new_weld_fail_count_SZ sizeof(ex_PULSE_DATA.new_weld_fail_count)
#define new_weld_status_SZ sizeof(ex_PULSE_DATA.new_weld_status)

//Then you define a network/message format
typedef struct
{
    byte new_weld_count[new_weld_count_SZ];
    byte new_weld_fail_count[new_weld_count_SZ];
    byte new_weld_status[new_weld_count_SZ];
} MESSAGE_FORMAT_PULSE_DATA;

然后你将实现序列化&反序列化功能在传输的两端.下面的例子很简单,但传达了你需要的要点.

byte*
PULSE_DATA_serialize( MESSAGE_FORMAT_PULSE_DATA* msg,NEW_PULSE_DATA* data )
{
    memcpy(&(msg->new_weld_count),data->new_weld_count,new_weld_count_SZ);
    memcpy(&(msg->new_weld_fail_count),data->new_weld_fail_count,new_weld_fail_count_SZ);
    memcpy(&(msg->new_weld_status),data->new_weld_status,new_weld_status_SZ);
    return msg;
}

NEW_PULSE_DATA*
PULSE_DATA_deserialize( NEW_PULSE_DATA* data,MESSAGE_FORMAT_PULSE_DATA* msg )
{
    memcpy(data->new_weld_count,&(msg->new_weld_count),new_weld_count_SZ);
    memcpy(data->new_weld_fail_count,&(msg->new_weld_fail_count),new_weld_fail_count_SZ);
    memcpy(data->new_weld_status,&(msg->new_weld_status),new_weld_status_SZ);
    return msg;
}

请注意,我省略了必须的网络字节顺序转换,因为我假设您已经解决了两个cpu域之间的字节顺序问题.如果你没有考虑字节顺序(big-endian和little-endian),那么你也需要解决这个问题.

发送邮件时,发件人执行以下操作,

//you need this declared & assigned somewhere
NEW_PULSE_DATA data;
//You need space for your message
MESSAGE_FORMAT_PULSE_DATA msg;
result = send(PULSE_DATA_deserialize( &data,&msg ));

收到邮件时,收件人会执行以下操作,

//recipient needs this declared somewhere
NEW_PULSE_DATA data;
//Need buffer to store received data
MESSAGE_FORMAT_PULSE_DATA msg;
result = receive(&msg,sizeof(msg));
//appropriate receipt checking here...
PULSE_DATA_deserialize( &data,&msg );