C SYNOPSIS

#include <pcp/pmapi.h>

int pmGetInDom(pmInDom indom, int **instlist, char ***namelist)
int pmRequestInDom(int ctx, pmInDom indom)
int pmReceiveInDom(int ctx, int **instlist, char ***namelist)

cc ... -lpcp

DESCRIPTION

In the current Performance Metrics Application Programming Interface (PMAPI) context, locate the description of the instance domain indom, and return via instlist the internal instance identifiers for all instances, and via namelist the full external identifiers for all instances. The number of instances found is returned as the function value (else less than zero to indicate an error).

The value for the instance domain indom is typically extracted from a pmDesc structure, following a call to pmLookupDesc(3) for a particular performance metric.

The resulting lists of instance identifiers (instlist and namelist), and the names that the elements of namelist point to, will have been allocated by pmGetInDom with two calls to malloc(3C), and it is the responsibility of the caller to free(instlist) and free(namelist) to release the space when it is no longer required.

When the result of pmGetInDom is less than one, both instlist and namelist are undefined (no space will have been allocated, and so calling free(3C) is a singularly bad idea).

pmRequestInDom and pmReceiveInDom are used by applications which must communicate with the PMCD asynchronously. These functions take explict context handle ctx which must refer to a host context (i.e. created by passing PM_CONTEXT_HOST to pmNewContext). pmRequestInDom sends request to enumerate all instances in the particular instance domain to PMCD and returns without waiting for the response, pmReceiveInDom reads reply from PMCD. It is the responsibility of the application to make sure the data are ready before calling pmReceiveInDom to avoid blocking.

PCP ENVIRONMENT

Environment variables with the prefix PCP_ are used to parameterize the file and directory names used by PCP. On each installation, the file /etc/pcp.conf contains the local values for these variables. The $PCP_CONF variable may be used to specify an alternative configuration file, as described in pcp.conf(4). Values for these variables may be obtained programatically using the pmGetConfig(3) function.

DIAGNOSTICS

PM_ERR_INDOM

indom is not a valid instance domain identifier

PM_ERR_CTXBUSY

Context is currently in use by another asynchronous call.