pmgetchildren(3) [centos man page]

PMGETCHILDREN(3)					     Library Functions Manual						  PMGETCHILDREN(3)

NAME

       pmGetChildren - return the descendent nodes of a PMNS node

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmGetChildren(const char *name, char ***offspring);

       cc ... -lpcp

DESCRIPTION

       Given  a  fully	qualified  pathname  to  a node in the current Performance Metrics Name Space (PMNS), as identified by name, pmGetChildren
       returns via offspring a list of the relative names of all of the immediate descendent nodes of name in the current PMNS.

       As a special case, if name is an empty string (i.e.""), the immediate descendants of the root node in the PMNS will be returned.

       Normally, pmGetChildren will return the number of descendent names discovered, else a value less than zero for an error.   The  value  zero
       indicates that name is a valid metric name, i.e. is associated with a leaf node in the PMNS.

       The  resulting  list  of  pointers  offspring  and  the values (the relative names) that the pointers reference will have been allocated by
       pmGetChildren with a single call to malloc(3C), and it is the responsibility of the pmGetChildren caller to free(offspring) to release  the
       space when it is no longer required.

       When  an  error	occurs,  or name is a leaf node (i.e. the result of pmGetChildren is less than one), offspring is undefined (no space will
       have been allocated, and so calling free(3C) is a singularly bad idea).

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 configura-
       tion file, as described in pcp.conf(5).	Values for these variables may be obtained programmatically using the pmGetConfig(3) function.

SEE ALSO

       PMAPI(3), pmGetChildrenStatus(3), pmGetConfig(3), pmLoadASCIINameSpace(3), pmLoadNameSpace(3), pmLookupName(3),	pmNameID(3),  pcp.conf(5),
       pcp.env(5) and pmns(5).

DIAGNOSTICS

       PM_ERR_NOPMNS
	      Failed  to access a PMNS for operation.  Note that if the application hasn't a priori called pmLoadNameSpace(3) and wants to use the
	      distributed PMNS, then a call to pmGetChildren must be made inside a current context.

       PM_ERR_NAME
	      The pathname name is not valid in the current PMNS

       PM_ERR_*
	      Other diagnostics are for protocol failures when accessing the distributed PMNS.

Performance Co-Pilot							PCP							  PMGETCHILDREN(3)

Check Out this Related Man Page

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)

Linux and UNIX Man Pages

pmgetchildren(3) [centos man page]

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