PMDAGETOPT(3)						     Library Functions Manual						     PMDAGETOPT(3)

NAME

       pmdaGetOpt - get options from argument vector, trapping generic PMDA options

C SYNOPSIS

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

       int pmdaGetOpt(int argc, char *const *argv, const char *optstring, pmdaInterface *dispatch, int *err);

       cc ... -lpcp_pmda -lpcp

DESCRIPTION

       This function is a wrapper for getopt(3).  The behavior of the function is identical except that certain options are assumed to have a pre-
       defined behavior which initializes several fields in the pmdaInterface structure.

       The options that pmdaGetOpt will trap are:

       -Dtrace	      Set the PMAPI(3) debug control variable (pmDebug) to trace.  Used for controlling levels of trace output while debugging.

       -ddomain       Set the domain number of this agent.

       -hhelpfile     Obtain the help text (see pmdaText(3)) for the metrics from this file rather than from the path specified with pmdaDSO(3) or
		      pmdaDaemon(3).

       -iport	      Expect PMCD to connect on inet port (number or name).

       -6port	      Expect PMCD to connect on ipv6 port (number or name).

       -llogfile      Redirect diagnostics and trace output to logfile.

       -p	      Expect PMCD to supply stdin/stdout pipe.

       -usocket       Expect PMCD to connect on unix domain socket.

       Only  one  of -i, -6, -p and -u may be specified.  If none of these three options is given, a pipe (-p) is assumed.  When these options are
       encountered by pmdaGetOpt, the option is processed and the next option is examined.  Therefore, pmdaGetOpt will only return when an  option
       other than those listed above is found, or the end of the list is reached.  The returned value will be the argument or EOF, respectively.

       A  PMDA can control which of these options the program will accept with the optstring argument.	To accept all the options, the PMDA should
       call pmdaGetOpt with the option string "D:d:h:i:l:pu:".	Any PMDA specific options  should  be  added  to  this	string	in  the  style	of
       getopt(3), and returned by pmdaGetOpt if encountered.  However, the PMDA cannot reuse any of the options specified above.

       pmdaGetOpt  takes a pointer to an int, err, which is used as an error count.  This variable should be initialized to zero before pmdaGetOpt
       is first called, and tested when pmdaGetOpt returns EOF.

       pmdaGetOpt does not modify argc or argv.

EXAMPLE

       A PMDA which takes the additional argument -n and does not use pmDebug might call pmdaGetOpt like this:

		pmdaInterface dispatch;
		int	      err = 0;
		int	      c = 0;

		while ((c = pmdaGetOpt(argv, argc, "d:h:i:l:pu:6:n:",
				       dispatch &err)) != EOF) {
		    /* process argument 'n', may use optarg etc. */
		}

		if (err)
		    usage(argv[0]);

       The global variables used by getopt (3) may be used by the caller of pmdaGetOpt within the argument parsing loop.

DIAGNOSTICS

       pmdaGetOpt will display the same error messages as getopt.

CAVEAT

       The options -D, -d, -i, -l, -p and -u cannot be reused for other purposes by the PMDA.

       The PMDA must be using PMDA_INTERFACE_2 or later, as specified in the call to pmdaDSO(3) or pmdaDaemon(3).

SEE ALSO

       pmdbg(1), getopt(3), PMAPI(3), PMDA(3), pmdaDaemon(3), pmdaDSO(3) and pmdaText(3).

Performance Co-Pilot							PCP							     PMDAGETOPT(3)