PMDADSO(3) Library Functions Manual PMDADSO(3)NAME
pmdaDSO - initialize the PMDA to run as a DSO
C SYNOPSIS
#include <pcp/pmapi.h>
#include <pcp/impl.h>
#include <pcp/pmda.h>
int pmdaDSO(pmdaInterface *dispatch, int interface, char *name, char *helptext);
cc ... -lpcp_pmda -lpcp
DESCRIPTION
pmdaDSO initializes the pmdaInterface structure to use the interface extensions, assuming the PMDA(3) is to be run as a DSO. The pmdaIn-
terface structure is initialized with:
name The name of the agent.
helptext The default path to the help text (see pmdaText(3). If no help text is installed, or you are not using pmdaText(3), then
this should be set to NULL.
The callbacks are initialized to pmdaProfile(3), pmdaFetch(3), pmdaDesc(3), pmdaText(3), pmdaInstance(3) and pmdaStore(3).
The interface structure also contains the domain of the PMDA(3), which is defined in the pmcd(1) configuration file. The domain is used to
initialize the metric and instance descriptors (see pmdaInit(3)).
DIAGNOSTICS
Incompatible version of pmcd detected
When pmcd(1) creates the pmdaInterface structure, the dispatch.comm.version field is set to the highest protocol that pm-
cd(1) understands. This message indicates that the pmcd(1) process does not understand the protocol used by pmdaDSO.
Unable to allocate memory for pmdaExt structure
In addition, dispatch->status is set to a value less than zero.
CAVEAT
The PMDA must be using PMDA_INTERFACE_2 or later.
SEE ALSO pmcd(1), PMAPI(3), PMDA(3), pmdaDaemon(3), pmdaInit(3) and pmdaText(3).
Performance Co-Pilot PCP PMDADSO(3)
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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)