Date: Sun, 9 Jun 2002 19:39:18 +0300 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: "Christopher J. Umina" <FJU@Fritzilldo.com> Cc: FreeBSD Questions <questions@FreeBSD.ORG> Subject: Re: Load Averages with C Message-ID: <20020609163918.GB1595@hades.hell.gr> In-Reply-To: <001901c20fe2$9988cc60$0301a8c0@uminafamily.com> References: <001201c20f54$46ba9e20$0301a8c0@uminafamily.com> <20020608222753.GA38586@hades.hell.gr> <001901c20fe2$9988cc60$0301a8c0@uminafamily.com>
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On 2002-06-09 11:22 -0700, Christopher J. Umina wrote:
> Why when I use getloadavg(3) do I come out with wierd numbers?
>
> This is my code.
>
> #include <stdio.h>
> #include <stdlib.h>
>
> int main(void) {
> int i;
> double loadavg[3];
> int getloadavg(double loadavg[], int nelem);
This is a prototype for getloadavg(). Since you included stdlib.h you
don't need this.
> for (i = 0; i < 3; ++i) {
> printf ("%d\n", loadavg[i]);
You are using the values of the loadavg[] array without having first
called getloadavg(). Your printfs will output whatever random garbage
happens to be on the stack (where loadavg[] is allocated, since it's a
local variable of the main() function).
Try this:
#include <stdio.h>
#include <stdlib.h>
int
main(void) {
int i;
double loadavg[3];
getloadavg(loadavg, 3);
for (i = 0; i < 3; ++i) {
printf (" %5.3lf", loadavg[i]);
}
printf("\n");
return (0);
}
Which seems to work nicely here:
19:36 [charon@hades /tmp]$ cc -Wall -W orig.foo.c
orig.foo.c: In function `main':
orig.foo.c:10: warning: int format, double arg (arg 2)
orig.foo.c:12: warning: control reaches end of non-void function
19:36 [charon@hades /tmp]$ cc -Wall -W foo.c
19:36 [charon@hades /tmp]$ ./a.out
1.663 1.466 0.970
19:36 [charon@hades /tmp]$ ./a.out
1.663 1.466 0.970
19:36 [charon@hades /tmp]$ ./a.out
1.663 1.466 0.970
- Giorgos
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