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Date: Sat, 7 Feb 2015 18:09:47 +1100 (EST)
From: Bruce Evans <brde@optusnet.com.au>
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To: "Simon J. Gerraty" <sjg@juniper.net>
Subject: Re: Buggy sbspace() on 64bit builds?
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Cc: Anuranjan Shukla <anshukla@juniper.net>,
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On Fri, 6 Feb 2015, Simon J. Gerraty wrote:

> Anuranjan Shukla <anshukla@juniper.net> wrote:
>> this, along with return value being 'int' acceptable as a final
>> determination?
>
> It is ok for the function to return long,
> so long as an int is used internally.
> Casting the int to long - implicit on return does no harm.
>
> #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\nr3=%ld\n", r1, r2, (long)r2);
>    exit(0);
> }
>
> r1=4294967295
> r2=-1
> r3=-1
>
> so I think just using 'int' internally should work for now,
> perhaps with a comment saying the object size should match
> those being subtracted etc.

Yes, that is simplest.

Bruce