Question

Possible Duplicate:
“long int”, “long long” Data Types

I am a newbie of C++ and I looked at a sample code and I saw long long type.
It says something like this

long long deviceId;

Is this same as long type? I am trying to send a device id from java(Android) to my server. In java, device id is long type(8byte) and I am putting this into the buffer like

bytebuffer.putLong(Long.valueOf(deviceId));

I am trying to parse this on my linux server using c++.

Thanks in advance.

Answer 1

long long is not the same as long (although they can have the same size, e.g. in most 64-bit POSIX system). It is just guaranteed that a long long is at least as long as a long. In most platforms, a long long represents a 64-bit signed integer type.

You could use long long to store the 8-byte value safely in most conventional platforms, but it’s better to use int64_t/int_least64_t from <stdint.h>/<cstdint> to clarify that you want an integer type having ≥64-bit.

#include <stdint.h>
...
int64_t deviceId;