User  |  Syst  |  Libr  |  Device  |  Files  |  Other  |  Admin  |  Head  |

---

   pmdachildren    ( 3 )

---

---

Имя (Name)

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

---

Синопсис C (C Synopsis)

#include <pcp/pmapi.h>
       #include <pcp/pmda.h>

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

       cc ... -lpcp_pmda -lpcp

---

Описание (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
       version.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 descendants 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(3), and the caller of
       pmdaChildren will call free(offspring) to release the space when
       it is no longer required.  The same holds true for the status
       array.

---

Предостережение (Caveat)

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

---

Диагностика (Diagnostic)

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

---

Смотри также (See also)

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

---