Re: getloadavg not universally available

[Phil D'Amore]

If anyone is interested, I had to write the attached for something a 
while back.  It emulates the Linux/Solaris interface to getloadavg() on 
a AIX box.  I have tested this against various 4.x incarnations of AIX 
but it has never been tested against 5.x.  Actually I'm not too fluent 
in AIX 5 but I'd be surprised if it does not contain this function already.

Later,

--
Phil D'Amore                             "Y'know, there was a time when
Senior System Administrator               corporate responsibility meant
Red Hat, Inc                              having the decency to jump out of
Office: 919.754.3700 x44395               a window when you got caught"
Cell:   919.641.3669                         -- Non-Sequitur, 09/30/2002


#include <stdio.h>
#include <nlist.h>
#include <errno.h>
#include <fcntl.h>

#define LOADAVG_1MIN 0
#define LOADAVG_5MIN 1
#define LOADAVG_15MIN 2

main(void)
{
    double loadavg[3];
    getloadavg(loadavg, 3);
    printf("Load average: %.2f, %.2f, %.2f\n", loadavg[0], loadavg[1],
                                               loadavg[2]);
}

getloadavg(double loadavg[], int nelem)
{
    struct nlist nl;
    int kmem, i;
    long avenrun[3];

    nl.n_name = "avenrun";
    nl.n_value = 0;

    if(knlist(&nl, 1, sizeof(nl)))
    {
        return -1;
    }

    if((kmem = open("/dev/kmem", 0, 0)) <= 0)
    {
        return -1;
    }

    if(pread(kmem, avenrun, sizeof(avenrun), nl.n_value) < sizeof(avenrun))
    {
        return -1;
    }

    for(i=0;i<nelem;i++)
    {
        loadavg[i] = (double) avenrun[i] / 65535;
    }
    return i;
}