hi,

is anyone out there familiar with the system call 'sysctl'? i'm trying to figure out what some source code (zebra) is doing:

#define MIBSIZ 6
int mib[MIBSIZ] =
{
CTL_NET,
PF_ROUTE,
0,
0, /* AF_INET & AF_INET6 */
NET_RT_IFLIST,
0
};

/* Query buffer size. */
if (sysctl (mib, MIBSIZ, NULL, &bufsiz, NULL, 0) < 0)
...

/* Fetch interface informations into allocated buffer. */
if (sysctl (mib, MIBSIZ, buf, &bufsiz, NULL, 0) < 0)
...

the first argument is an array of ints, second one says how big the array is. the other args are buffers and sizes for the value read and the value to write.

i guess what i need to know is the format and content of the first argument. where is this defined?

cheers,
john c.
PS redhat 7.2, kernel 2.4.2-2

if you try to get a man page on this, you'll probably com up with info about a shell command to set kernel parameters.... that's not what you're looking for. here's a man page to the c call - it's a pretty involved function:

http://www.ajk.tele.fi/libc/gen/sysctl.3.html

hey isajera,

thanks for the info. that man page is actually a bit more helpful than the section 2 one i was looking at on my system. it appears redhat 7.1 does not install the section 3 man page for this call by default (or maybe it does - i didn't install it myself).

john c.