Question

If you have an object

struct Packet P;

that consists of

struct Packet {
    struct Packet_header header;
    unsigned char data[MAXIMUM_BUFFER_LENGTH];
};

and the header consists of

struct Packet_header {
    unsigned int checksum;
    unsigned int seq;
    unsigned int ack;
    unsigned int data_length;
};

If I try to cast the packet

(unsigned char*) &P

is there anyway I can “uncast” back to get my original packet P?

Answer 1

unsigned char *p = (unsigned char*) &P;
Packet *pPacket = (Packet *)p;