Copy One Struct Member to Another Struct

I’m struggling with this syntax: I have a few structs of arrays:

struct Msg {
    uint8_t Data[DATA_SIZE];
};

struct Msg Msg_Buff[NUM_MESSAGES], Temp_Buff[NUM_MESSAGES];

and want to copy one array from one struct to another.

This:

*Temp_Buff[Other_Indx].Data = *Msg_Buff[This_Indx].Data;

copies ONLY the first element of the array, not the whole array. What am I doing wrong?

>Solution :

You need to use memcpy for that if you want to copy only one member.

#define DATA_SIZE 100
#define NUM_MESSAGES 200

struct Msg {
    uint8_t Data[DATA_SIZE];
};

struct Msg Msg_Buff[NUM_MESSAGES], Temp_Buff[NUM_MESSAGES];


void copyDataAtIndex(size_t index)
{
    memcpy(Temp_Buff[index].Data, Msg_Buff[index].Data, sizeof(Temp_Buff[index].Data));
}

If you want to copy the whole struct – simply assign:

void copyStructAtIndex(size_t index)
{
    Temp_Buff[index] = Msg_Buff[index];
}