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From: orachat@seashell.seas.ucla.edu (Orachat Choedamphai)
Newsgroups: comp.unix.aux
Subject: How do I read the load average values from /dev/kmem?
Message-ID: <480@lee.SEAS.UCLA.EDU>
Date: 23 Mar 90 01:37:27 GMT
Sender: news@SEAS.UCLA.EDU
Reply-To: orachat@seashell.seas.ucla.edu (Orachat Choedamphai)
Distribution: usa
Organization: SEASnet, University of California, Los Angeles
Lines: 45

Hello,

I'm trying to get the value of the variable "avenrun" from /dev/kmem. The
following is a program that I used.  Could someone please tell me what I did
wrong or maybe someone could send me a C program that will do this job? 
I would appreciate any help or suggestion.  Thank you in advance.

_Orachat
 
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/file.h>
#include <a.out.h> 

#define  UNIX 	"/unix"

int 	kmemf;  /* descriptor of /dev/kmem */	

struct nlist nl[2];

extern int errno;

main ()
{
	float avenrun[3];

	(void) strcpy (nl[0].n_name, "avenrun");
	(void) strcpy (nl[1].n_name, "0");
        nlist(UNIX, nl);
	if (nl[0].n_value == 0) {
                fprintf (stderr, "/vmunix: No namelist\n");  
		exit(1);
        }
	 printf ("address = %d\n", nl[0].n_value);
        if ((kmemf = open("/dev/kmem", O_RDONLY)) < 0) {
                perror ("/dev/kmem");
                exit (1);
        }
        if (lseek (kmemf, (off_t)nl[0].n_value, 0) < 0)
		printf ("lseek failed\n");;
        (void) read (kmemf, (char *)avenrun, sizeof(avenrun));
	 printf ("load = %e,%e,%e\n", avenrun[0], avenrun[1], avenrun[2]); 
}