Writing 64 bit int value to NSOutputStream

Question

I'm having trouble communicating position coordinates to a set of motors I have connected on the network. I can send a string just fine, and receive text back from the motor, but I can't seem to send it an int value.

Using NSlog I have determined that the actual value I'm sending is correct, however I suspect my method of sending it via the output stream is wrong. Any ideas?

My code for sending a 64bit int value:

uint64_t rawInt = m1; 
rawInt <<= 16; 
rawInt |= m2;
NSData *buffer = [NSData dataWithBytes: &rawInt length:8];
[outputStream write: [buffer bytes] maxLength:[buffer length]];

Answer 1

Well, your codes looks kind of funny. Anyway, for sending a binary integer over the network, you have to know the endianess: The receiver either expects little or big endian integers.

Here's the code for both:

uint64_t myInt = 42;

uint64_t netInt = CFSwapInt64HostToLittle(myInt); // use this for little endian
uint64_t netInt = CFSwapInt64HostToBig(myInt);    // use this for big endian

[outputStream write:(uint8_t*)&netInt maxLength:sizeof(netInt)];