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NAME | C SYNOPSIS | DESCRIPTION | CAVEAT | DIAGNOSTICS | SEE ALSO | COLOPHON |
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PMDAGETOPTIONS(3) Library Functions Manual PMDAGETOPTIONS(3)
pmdaGetOpt, pmdaGetOptions - get options from arguments, parsing
generic PMDA options
#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
These functions are wrappers for pmgetopt_r(3). The behavior of
each function is that certain options are assumed to have a prede‐
fined behavior which initializes several fields in the pmdaInter‐
face 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 de‐
scribed 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 op‐
tions, and store them within the opts parameter:
-Uusername
Set the user account name under which the PMDA should exe‐
cute.
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 op‐
tions are encountered by pmdaGetOpt, the option is processed and
the next option is examined. Therefore, pmdaGetOpt will only re‐
turn when an option other than those listed above is found, or the
end of the list is reached. The returned value will be the argu‐
ment 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 op‐
tions, 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 spe‐
cific options should be added to these strings in the style of
getopt(3), and will be returned by both pmdaGetOptions and pmdaGe‐
tOpt if encountered.
When a command line option usage error is detected in the pmdaGe‐
tOptions 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 er‐
ror 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 pars‐
ing loop.
On the other hand, the pmdaGetOptions interface does not utilize
global variables at all (neither reading nor modifying them). In‐
stead, these variables can be access via the opts fields of the
same name.
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).
Both pmdaGetOptions and pmdaGetOpt will display the same error
messages as getopt.
pmdbg(1), getopt(3), pmgetopt_r(3), pmGetOptions(3), PMAPI(3),
PMDA(3), pmdaDaemon(3), pmdaDSO(3) and pmdaText(3).
This page is part of the PCP (Performance Co-Pilot) project. In‐
formation about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
pcp@groups.io. This page was obtained from the project's upstream
Git repository ⟨https://github.com/performancecopilot/pcp.git⟩ on
2025-08-11. (At that time, the date of the most recent commit
that was found in the repository was 2025-08-11.) If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a
mail to man-pages@man7.org
Performance Co-Pilot PCP PMDAGETOPTIONS(3)
Pages that refer to this page: pmda(3), pmdaconnect(3), pmdadaemon(3), pmdainit(3), pmdaopenlog(3), pmdatext(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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