Converting struct to byte and back to struct

Steven10172 picture Steven10172 · Dec 8, 2012 · Viewed 50.1k times · Source

I'm currently working with Arduino Unos, 9DOFs, and XBees, and I was trying to create a struct that could be sent over serial, byte by byte, and then re-constructed into a struct.

So far I have the following code:

struct AMG_ANGLES {
    float yaw;
    float pitch;
    float roll;
};

int main() {
    AMG_ANGLES struct_data;

    struct_data.yaw = 87.96;
    struct_data.pitch = -114.58;
    struct_data.roll = 100.50;

    char* data = new char[sizeof(struct_data)];

    for(unsigned int i = 0; i<sizeof(struct_data); i++){
        // cout << (char*)(&struct_data+i) << endl;
        data[i] = (char*)(&struct_data+i); //Store the bytes of the struct to an array.
    }

    AMG_ANGLES* tmp = (AMG_ANGLES*)data; //Re-make the struct
    cout << tmp.yaw; //Display the yaw to see if it's correct.
}

Source: http://codepad.org/xMgxGY9Q

This code doesn't seem to work, and I'm not sure what I'm doing wrong.

How do I solve this?

Answer

Steven10172 picture Steven10172 · Dec 8, 2012

It seems I've solved my issue with the following code.

struct AMG_ANGLES {
    float yaw;
    float pitch;
    float roll;
};

int main() {
    AMG_ANGLES struct_data;

    struct_data.yaw = 87.96;
    struct_data.pitch = -114.58;
    struct_data.roll = 100.50;

    //Sending Side
    char b[sizeof(struct_data)];
    memcpy(b, &struct_data, sizeof(struct_data));

    //Receiving Side
    AMG_ANGLES tmp; //Re-make the struct
    memcpy(&tmp, b, sizeof(tmp));
    cout << tmp.yaw; //Display the yaw to see if it's correct
}

WARNING: This code will only work if sending and receiving are using the same endian architecture.