centos man page for pmdachildren

PMDACHILDREN(3) 					     Library Functions Manual						   PMDACHILDREN(3)

NAME
       pmdaChildren - translate a PMID to a set of dynamic performance metric names

C SYNOPSIS
       #include <pcp/pmapi.h>
       #include <pcp/impl.h>
       #include <pcp/pmda.h>

       int pmdaChildren(char *name, int traverse, char ***offspring, int **status, pmdaExt *pmda);

       cc ... -lpcp_pmda -lpcp

DESCRIPTION
       As part of the Performance Metrics Domain Agent (PMDA) API (see PMDA(3)), pmdaChildren is the generic callback for returning dynamic metric
       names (and their status) that are descendants of name.

       Because implementing dynamic performance metrics requires specific PMDA support, and the facility is an optional component of a PMDA  (most
       PMDAs do not support dynamic performance metrics), pmdaChildren is a skeleton implementation that returns PM_ERR_NAME.

       A  PMDA	that  supports	dynamic  performance  metrics  will  provide  a private callback that replaces pmdaChildren (by assignment to ver-
       sion.four.children of the pmdaInterface structure) and takes the initial metric name and returns names via offspring[] and the leaf or non-
       leaf status of each via status[].

       If traverse is 0, then the behaviour is akin to pmGetChildren(3) and offspring[] contains the relative name component for the immediate de-
       scendants of name.

       If traverse is 1, then the behaviour is akin to pmTraversePMNS(3) and offspring[] contains the absolute names of all dynamic  metrics  that
       are decedents of name.

       The  resulting  list  of pointers offspring and the values (the names) that the pointers reference will have been allocated by pmdaChildren
       with a single call to malloc(3C), and the caller of pmdaChildren will call free(offspring) to release the space when it is  no  longer  re-
       quired.	The same holds true for the status array.

DIAGNOSTICS
       pmdaChildren  returns  PM_ERR_NAME  if  the name is not recognized or cannot be translated, otherwise the number of descendent metric names
       found.

CAVEAT
       The PMDA must be using PMDA_PROTOCOL_4 or later, as specified in the call to pmdaDSO(3) or pmdaDaemon(3).

SEE ALSO
       PMAPI(3), PMDA(3), pmdaDaemon(3), pmdaDSO(3), pmdaMain(3), pmGetChildren(3) and pmTraversePMNS(3).

Performance Co-Pilot							PCP							   PMDACHILDREN(3)