Using lgrp_cpus()

The lgrp_cpus(3LGRP) function takes a cookie that represents a snapshot of the lgroup hierarchy and returns the number of CPUs in a given lgroup.

#include <sys/lgrp_user.h>
int lgrp_cpus(lgrp_cookie_t cookie, lgrp_id_t lgrp, processorid_t *cpuids,
              uint_t count, int content);

If the cpuid[] argument is not NULL and the CPU count is not zero, the lgrp_cpus() function fills the array with CPU IDs until the array is full or all the CPU IDs are in the array.

The content argument can have the following two values:

LGRP_CONTENT_ALL

The lgrp_cpus() function returns IDs for the CPUs in this lgroup and this lgroup's descendants.

LGRP_CONTENT_DIRECT

The lgrp_cpus() function returns IDs for the CPUs in this lgroup only.

The lgrp_cpus() function returns EINVAL when the cookie, lgroup ID, or one of the flags is not valid. The lgrp_cpus() function returns ESRCH when the specified lgroup ID is not found.