It says on wikipedia and in Stroustrup's FAQ that type long long is at least as long as an int and has no fewer than 64 bits. I have been looking at the C++11 standard §3.9.1 Fundamental Types section and I cannot find any reference to 64 bits. All I can find is that it is at least as long at long int, which is at least as long as int. The standard lists long long as a standard integer type, as opposed to an extended one, so I am wondering whether this assertion that long long holds at least 64 bits is true. And if it is, where is it stated?
Please note that I am talking about C++11 standard long long only.
The C++ standard references the C standard for this, see [c.limits]. LLONG_MAX is defined in <climits> with the same meaning as C's <limits.h>'s LLONG_MAX. And this is what C has to say:
5.2.4.2.1 Sizes of integer types
<limits.h>The values given below shall be replaced by constant expressions suitable for use in
#ifpreprocessing directives. [...] Their implementation-defined values shall be equal or greater in magnitude (absolute value) to those shown, with the same sign.[...]
-- maximum value for an object of type
long long int
LLONG_MAX +9223372036854775807 //263 -1
A signed type that must be capable of representing the value 9223372036854775807 requires 64 bits or more.