PMADDDERIVEDTEXT(3)        Library Functions Manual        PMADDDERIVEDTEXT(3)

NAME
       pmAddDerivedText - add help text for a derived metric

C SYNOPSIS
       #include <pcp/pmapi.h>

       int pmAddDerivedText(const char *name, int type, const char *text);

       cc ... -lpcp

DESCRIPTION
       Derived metrics provide a way of extending the Performance Metrics Name
       Space (PMNS) with new metrics defined at the PCP client-side using
       expressions over the existing performance metrics.  Global derived
       metrics are defined using pmRegisterDerived(3) or
       pmRegisterDerivedMetric(3) or pmLoadDerivedConfig(3), and per-context
       derived metrics are defined using pmAddDerived(3) or
       pmAddDerivedMetric(3).

       Once a derived metric has been defined, pmAddDerivedText may be used to
       associate the help text with the derived metric identified by name.

       Help text may be a ``one line'' summary or a more verbose ``multi-
       line'' block of text, and type should be PM_TEXT_ONELINE or
       PM_TEXT_HELP respectively.  To associate both styles of help text with
       a derived metric, pmAddDerivedText would need to be called twice with
       different values for type.

       Once a particular type of help text has been associated with a derived
       metric it cannot be deleted or redefined.

       Applications using the Performance Metrics Application Programming
       Interface (PMAPI) are able to retrieve help text for specific metrics
       using pmLookupText(3).

DIAGNOSTICS
       pmAddDerivedText returns zero on success, else an error code.

       The return value PM_ERR_NAME indicates name does not correspond to a
       previously defined derived metric.

       Repeated calls for the same name and type will result a return value of
       PM_ERR_TEXT.

       A return value of PM_ERR_ARG indicates that type is not one of the
       expected values.

SEE ALSO
       PCPIntro(1), pmAddDerived(3), pmAddDerivedMetric(3), PMAPI(3),
       pmLoadDerivedConfig(3), pmLookupText(3), pmRegisterDerived(3),
       pmRegisterDerivedMetric(3) and PMNS(5).

Performance Co-Pilot                                       PMADDDERIVEDTEXT(3)