pmdahelp(3) — Linux manual page


PMDAHELP(3)             Library Functions Manual             PMDAHELP(3)

NAME         top

       pmdaOpenHelp, pmdaGetHelp, pmdaGetInDomHelp, pmdaCloseHelp - help
       text support for a PMDA

C SYNOPSIS         top

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

       int pmdaOpenHelp(const char *fname);
       char *pmdaGetHelp(int handle, pmID pmid, int type);
       char *pmdaGetInDomHelp(int handle, pmInDom indom, int type);
       void pmdaCloseHelp(int handle);

       cc ... -lpcp_pmda -lpcp

DESCRIPTION         top

       As part of the Performance Metrics Domain Agent (PMDA) API (see
       PMDA(3)), this group of routines is used to implement the
       processing of a PMDA's metric help information.

       These routines are really intended for internal use, and should
       not need to be called directly from any PMDA code.

       Briefly, the base name of the help text file (as created by
       newhelp(1)) is passed in via a -h command line option for a
       daemon PMDA or as an argument to pmdaDaemon(3) or pmdaDSO(3).
       Then pmdaOpenHelp is called from pmdaInit(3) and returns a handle
       that is used in subsequent calls to identify a particular help
       text collection (each PMDA typically has only one such

       Requests for help text are passed to pmdaText(3) which calls
       pmdaGetHelp or pmdaGetInDomHelp as required.

       Other than error cases in pmdaOpenHelp, pmdaCloseHelp is not

CAVEAT         top

       The PMDA must be using PMDA_PROTOCOL_2 or later, as specified in
       the call to pmdaDSO(3) or pmdaDaemon(3).

DIAGNOSTICS         top

       pmdaOpenHelp returns a negative value for failure, suitable for
       decoding with pmErrStr(3).  pmdaGetHelp and pmdaGetInDomHelp
       return NULL if the corresponding help text does not exist.

SEE ALSO         top

       newhelp(1), PMAPI(3), PMDA(3), pmdaDaemon(3), pmdaDSO(3),
       pmdaInit(3), pmdaText(3) and pmErrStr(3).

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.
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       ⟨⟩ on 2023-12-22.
       (At that time, the date of the most recent commit that was found
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Performance Co-Pilot               PCP                       PMDAHELP(3)