KSTAT_CHAIN_UPDATE(3KSTAT)KSTAT_CHAIN_UPDATE(3KSTAT)NAMEkstat_chain_update - update the kstat header chain
SYNOPSIS
cc [ flag... ] file... -lkstat [ library...]
#include <kstat.h>
kid_t kstat_chain_update(kstat_ctl_t *kc);
DESCRIPTION
The kstat_chain_update() function brings the user's kstat header chain
in sync with that of the kernel. The kstat chain is a linked list of
kstat headers (kstat_t's) pointed to by kc->kc_chain, which is initial‐
ized by kstat_open(3KSTAT). This chain constitutes a list of all kstats
currently in the system.
During normal operation, the kernel creates new kstats and delete old
ones as various device instances are added and removed, thereby causing
the user's copy of the kstat chain to become out of date. The
kstat_chain_update() function detects this condition by comparing the
kernel's current kstat chain ID (KCID), which is incremented every time
the kstat chain changes, to the user's KCID, kc->kc_chain_id. If the
KCIDs match, kstat_chain_update() does nothing. Otherwise, it deletes
any invalid kstat headers from the user's kstat chain, adds any new
ones, and sets kc->kc_chain_id to the new KCID. All other kstat headers
in the user's kstat chain are unmodified.
RETURN VALUES
Upon successful completion, kstat_chain_update() returns the new KCID
if the kstat chain has changed and 0 if it has not changed. Otherwise,
it returns −1 and sets errno to indicate the error.
ERRORS
The kstat_chain_update() function will fail if:
EAGAIN
The kstat was temporarily unavailable for reading or writ‐
ing.
ENOMEM
Insufficient storage space is available.
ENXIO
The given kstat could not be located for reading.
EOVERFLOW
The data for the given kstat was too large to be stored in
the structure.
FILES
/dev/kstat
kernel statistics driver
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Stable │
├────────────────────┼─────────────────┤
│MT-Level │ Unsafe │
└────────────────────┴─────────────────┘
SEE ALSOkstat(3KSTAT), kstat_lookup(3KSTAT), kstat_open(3KSTAT),
kstat_read(3KSTAT), attributes(5)
Aug 3, 2004 KSTAT_CHAIN_UPDATE(3KSTAT)
