// on a big-endian 64-bit machine
struct Message {
int32_t a;
int16_t b;
char c;
char padding;
};
// send over a socket
Message msg = {12345, 678, 'x', 0};
send(fd, &msg, sizeof Message, 0);
// another machine: a little-endian 64-bit machine
char buffer[1024];
if (recv(fd, buffer, sizeof buffer, 0)) {
Message msg;
// or we can use the union trick
memcpy(&msg, buffer, sizeof Message); SomeFunctioToConvertFromBigEndianToSmallEndian(msg.a);
SomeFunctioToConvertFromBigEndianToSmallEndian(msg.b);
}
On Monday, September 15, 2014 7:33 PM, Andrew Haley <aph@xxxxxxxxxx> wrote:
On 09/15/2014 12:29 PM, Hei Chan wrote:
>
>
>
>
>
> On Monday, September 15, 2014 7:22 PM, Andrew Haley <aph@xxxxxxxxxx> wrote:
>
>> Using memcpy(), the compiler will have to make a copy
>> because it sees that few lines, for example, down, the program tries
>> to manipulate the copy.
>
> So, don't manipulate the copy, then. Use it once, then throw it away.
>
> Sometimes, due to the endianness, I am forced to manipulate the copy...
I don't know what you mean. A small example would help.
Andrew.
