NAME

       pmdaGetOpt, pmdaGetOptions - get options from arguments, parsing generic PMDA options

C SYNOPSIS

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

       int pmdaGetOptions(int argc, char *const *argv, pmdaOptions *opts, pmdaInterface *dispatch);

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

       cc ... -lpcp_pmda -lpcp

DESCRIPTION

       These  functions  are  wrappers for pmgetopt_r(3).  The behavior of each function is that certain options
       are assumed to have  a  predefined  behavior  which  initializes  several  fields  in  the  pmdaInterface
       structure.   The  pmdaGetOptions  interface  allows  both  short  and  long  options to be given, whereas
       pmdaGetOpt allows for short form options only.

       The options that both pmdaGetOptions and pmdaGetOpt will trap are:

       -Ddebugspec    Set the PMAPI(3) debugging options to debugspec, as described in  PCPIntro(1).   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.

       The pmdaGetOptions interface will also capture the following options, and  store  them  within  the  opts
       parameter:

       -Uusername     Set the user account name under which the PMDA should execute.

       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  either  the  opts  or  optstring
       argument.  To accept all the options, the PMDA should call pmdaGetOptions with the short_options field of
       the opts structure set to the PMDA_OPTIONS macro, or pmdaGetOpt with the option  string  "D:d:h:i:l:pu:".
       Any  PMDA  specific  options  should  be  added  to  these strings in the style of getopt(3), and will be
       returned by both pmdaGetOptions and pmdaGetOpt if encountered.

       When a command line option usage error is detected in the pmdaGetOptions interface, the  error  field  of
       the opts structure will contain a non-zero error count.

       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.

       Neither pmdaGetOptions nor pmdaGetOpt modify their argc or argv parameters.

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

       On the other hand, the pmdaGetOptions interface does not utilize global variables at all (neither reading
       nor modifying them).  Instead, these variables can be access via the opts fields of the same name.

CAVEAT

       The options -D, -d, -i, -l, -p and -u cannot be reused for other purposes by the PMDA, unless  using  the
       override method provided by the pmdaGetOptions interface, which operates in the same way as described for
       the pmGetOptions(3) interface used by PMAPI client tools.

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

DIAGNOSTICS

       Both pmdaGetOptions and pmdaGetOpt will display the same error messages as getopt.

SEE ALSO

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