noble (3) pmGetChildren.3.gz

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(3), 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(3) is a singularly bad
       idea).

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.

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(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).