Q:

In C++, what data type does the operator sizeof returns?

When I compile this line in Qt:
printf("size: %d\n", sizeof(fValue)); 

I get this warning:

"Format specifies type 'int' but the argument has type 'unsigned long
  long' "

so I deduce that the data type is 'unsigned long long', but I cannot find that information written anywhere.
Thanks.

A:

sizeof() returns a std::size_t, which is an implementation-defined unsigned integer.  In your case, your compiler is using unsigned long long.

