Buggy sbspace() on 64bit builds?

[Simon J. Gerraty]

Poul-Henning Kamp <phk at phk.freebsd.dk> wrote:
> >Any thoughts on what a fix should be for this?
> 
> size_t or intptr_t ?

I don't think so, the bug lies in the fact that on 64bit long is much
bigger than the uint's that are being manipulated.
Using a result object the same size works.

Here's a simple demo of the problem:

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>

int
main(int argc, char *argv[])
{
    uint a, b;
    long r1;
    int r2;

    a = 1;
    b = 2;

    r1 = a - b;
    r2 = a - b;

    printf("r1=%ld\nr2=%d\n", r1, r2);
    exit(0);
}

32bit version outputs:

r1=-1
r2=-1

64bit version outputs:

r1=4294967295
r2=-1

the r1 value is obviously not what is expected by the caller.