NAME
pmdaOpenHelp, pmdaGetHelp, pmdaGetInDomHelp, pmdaCloseHelp, - help text
support for a PMDA
C SYNOPSIS
#include <pcp/pmapi.h>
#include <pcp/impl.h>
#include <pcp/pmda.h>
int pmdaOpenHelp(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.
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.
CAVEAT
The PMDA must be using PMDA_PROTOCOL_2 or later, as specified in the
call to pmdaDSO(3) or pmdaDaemon(3).
SEE ALSO
newhelp(1), PMAPI(3), PMDA(3), pmdaDaemon(3), pmdaDSO(3), pmdaInit(3),
pmdaText(3) and pmErrStr(3).