NAME

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

C SYNOPSIS

       #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

       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 collection).

       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 called.

CAVEAT

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

DIAGNOSTICS

       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

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