Re: Easy c debugging question

[Dennis Melentyev <dmelentyev@xxxxxxxxx>]

Hi,

walt wrote:
> I wrote this trivial c program to practice using libkinfo:
>
> #include <sys/param.h>
> #include <kinfo.h>
> int main()
> {
> struct kinfo_cputime *k;
> kinfo_get_sched_cputime(k);
>
> printf("user=%16d\n", k->cp_user);
> printf("nice=%16d\n", k->cp_nice);
> printf("sys=%16d\n", k->cp_sys);
> printf("intr=%16d\n", k->cp_intr);
> printf("idle=%16d\n", k->cp_idle);
> }
> It works as I expected when compiled with dynamic linking,
> but it dumps core when statically linked.  gdb tells me
> it exits at the first printf with 'code 026', which means
> nothing to me.
>
> Any hints what I'm doing wrong?

The hint:

Just use -Wformat or even -Wall, -pedantic and -Werror in gcc command 
line and _*READ*_ the warnings.

The problem description:

As of http://fxr.watson.org/fxr/source/sys/kinfo.h?v=DFBSD:
 54 struct kinfo_cputime {
 55         uint64_t        cp_user;
 56         uint64_t        cp_nice;
 57         uint64_t        cp_sys;
 58         uint64_t        cp_intr;
 59         uint64_t        cp_idle;
 60 };

So, you're trying to spoil the stack putting there 64bit values but 
extracting the 32bit ones...

--
Dennis Melentyev
http://www.melentyev.kiev.ua/dennis