What should be the exact size of for unsigned long long

Question

What should be the exact typedef for unsigned long long ?
For example:

typedef unsigned int uint32 ; //considering my machine reading
typedef unsigned char byte ;

So what is

typedef unsigned long long ______ ;

Is it uint64 or more than this?

None. Its size is not fixed to one value. There is only a requirement on its minimum size. — juanchopanza, Jan 17 '14 at 10:57
Why do you typedef int to 'uint32'? Isn't uint used for unsigned integers? — rajatkhanduja, Jan 17 '14 at 11:02
Please fix the `typedef int uint32 ;`, Some unsuspecting newbie will eventually copy/paste it into code somewhere. Reminds me of code that's been seen in the wild that defines `TRUE` to be `0` and `FALSE` to be `1` by carelessly declaring them in an enum. — Michael Burr, Jan 17 '14 at 11:07
See this C++ question too: http://stackoverflow.com/questions/10053113/is-c11s-long-long-really-at-least-64-bits — juanchopanza, Jan 17 '14 at 11:33

score 1 · Answer 1 · answered Jan 17 '14 at 11:05

1

unsigned long long is guaranteed to be at least 64 bits in size. Thus, it is equivalent to uint_least64_t:

typedef unsigned long long uint_least_64_t

answered Jan 17 '14 at 11:05

Filipe Gonçalves

Given current platforms, they are typically equivalent. An esoteric/future C compliant platform may have `unsigned long long` as 128-bit unsigned and `unsigned long` as a 64-bit unsigned. Such a system would not maintain that equivalent with `typedef unsigned long uint_least64_t;`. – chux - Reinstate Monica Jan 17 '14 at 17:17

score 0 · Answer 2 · edited May 23 '17 at 10:31

0

unsigned long long my_variable;

means my_variable is an unsigned integer value of 64 bits (or more)

you may find helpfult this too:

unsigned long long

is a synonim of

unsigned long long int

that is defined as

typedef unsigned long long int uint64_t

see

edited May 23 '17 at 10:31

Community

answered Jan 17 '14 at 10:58

Paolo

`unsigned long long int` is not defined as `uint64_t`. `uint64_t` _may_ be defined as `unsigned long long int`, the reverse is not specified by C. – chux - Reinstate Monica Jan 17 '14 at 17:09

2 Answers2