pmaddderivedtext(3) — Linux manual page

NAME | C SYNOPSIS | DESCRIPTION | DIAGNOSTICS | SEE ALSO | COLOPHON

PMADDDERIVEDTEXT(3)      Library Functions Manual     PMADDDERIVEDTEXT(3)

NAME         top

       pmAddDerivedText - add help text for a derived metric

C SYNOPSIS         top

       #include <pcp/pmapi.h>

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

       cc ... -lpcp

DESCRIPTION         top

       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         top

       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         top

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

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.
       Information about the project can be found at 
       ⟨http://www.pcp.io/⟩.  If you have a bug report for this manual
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       ⟨https://github.com/performancecopilot/pcp.git⟩ on 2025-02-02.
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Performance Co-Pilot                                  PMADDDERIVEDTEXT(3)