1PMADDDERIVEDTEXT(3) Library Functions Manual PMADDDERIVEDTEXT(3)
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6 pmAddDerivedText - add help text for a derived metric
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9 #include <pcp/pmapi.h>
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11 int pmAddDerivedText(const char *name, int type, const char *text);
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13 cc ... -lpcp
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16 Derived metrics provide a way of extending the Performance Metrics Name
17 Space (PMNS) with new metrics defined at the PCP client-side using ex‐
18 pressions over the existing performance metrics. Global derived met‐
19 rics are defined using pmRegisterDerived(3) or pmRegisterDerivedMet‐
20 ric(3) or pmLoadDerivedConfig(3), and per-context derived metrics are
21 defined using pmAddDerived(3) or pmAddDerivedMetric(3).
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23 Once a derived metric has been defined, pmAddDerivedText may be used to
24 associate the help text with the derived metric identified by name.
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26 Help text may be a ``one line'' summary or a more verbose ``multi-
27 line'' block of text, and type should be PM_TEXT_ONELINE or
28 PM_TEXT_HELP respectively. To associate both styles of help text with
29 a derived metric, pmAddDerivedText would need to be called twice with
30 different values for type.
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32 Once a particular type of help text has been associated with a derived
33 metric it cannot be deleted or redefined.
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35 Applications using the Performance Metrics Application Programming In‐
36 terface (PMAPI) are able to retrieve help text for specific metrics us‐
37 ing pmLookupText(3).
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40 pmAddDerivedText returns zero on success, else an error code.
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42 The return value PM_ERR_NAME indicates name does not correspond to a
43 previously defined derived metric.
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45 Repeated calls for the same name and type will result a return value of
46 PM_ERR_TEXT.
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48 A return value of PM_ERR_ARG indicates that type is not one of the ex‐
49 pected values.
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52 PCPIntro(1), pmAddDerived(3), pmAddDerivedMetric(3), PMAPI(3), pmLoad‐
53 DerivedConfig(3), pmLookupText(3), pmRegisterDerived(3), pmRegister‐
54 DerivedMetric(3) and PMNS(5).
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58Performance Co-Pilot PMADDDERIVEDTEXT(3)