在32位应用程序中使用uint64_t

Question

Due to some libraries, I have to compile my application in 32 bit, but I need to use integer variables that exceed the max number of 32 bit types. So for example if I try to use uint64_t I get an overflow at 2147483647 .

I thought it is possible to use 64 bit integer variables in 32 bit application, so what did I miss here? Do I have to include some specific header oder do I have to set some option therefore? Using VS17.

EDIT:

I did some testing, and in this example program, I can reproduce my overflow problem.

#include <iostream>

int main()
{
    uint64_t i = 0;

    while (true)
    {
        std::printf("%d\n",i);
        i += (uint64_t)10000;
    }
    return 0;
}

Answer 1

The bug is here:

 std::printf("%d\\n",i); ^^ 

You've used the wrong format specifier, and therefore the behaviour of the program is undefined. %d is for signed int . You need to use

std::printf("%" PRIu64 "\n",i);

PRIu64 is declared in <cinttypes> .

PS You also haven't included the header which declares std::printf .