pmdadso(3) — Linux manual page

NAME | C SYNOPSIS | DESCRIPTION | CAVEAT | DIAGNOSTICS | SEE ALSO | COLOPHON

PMDADSO(3)               Library Functions Manual              PMDADSO(3)

NAME         top

       pmdaDSO - initialize the PMDA to run as a DSO

C SYNOPSIS         top

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

       int pmdaDSO(pmdaInterface *dispatch, int interface, char *name,
               char *helptext);

       cc ... -lpcp_pmda -lpcp

DESCRIPTION         top

       pmdaDSO  initializes the pmdaInterface structure to use the inter‐
       face extensions, assuming the PMDA(3) is to be run as a DSO.   The
       pmdaInterface 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, otherwise helptext will be
              copied, so the storage associated with helptext may be re‐
              leased after the call to pmdaDSO.

       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)).

CAVEAT         top

       The PMDA must be using PMDA_INTERFACE_2 or later.

       Once pmdaDSO has been called, it is expected that the pmdaInter‐
       face structure pointed to by dispatch will remain accessible to
       the routines in libpcp_pmda (not reclaimed off the stack, not
       freed or otherwise released, etc.).  If the caller needs to move
       or relocate the pmdaInterface structure for any reason, then after
       the move pmdaInterfaceMoved(3) must be called to re-establish the
       internal integrity of the pmdaInterface structure at the new loca‐
       tion before any other routine in libpcp_pmda is called.

DIAGNOSTICS         top

       Incompatible version of pmcd detected
              When pmcd(1) creates the pmdaInterface structure, the dis‐
              patch.comm.version field is set to the highest protocol
              that pmcd(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.

SEE ALSO         top

       pmcd(1), PMAPI(3), PMDA(3), pmdaDaemon(3), pmdaInit(3),
       pmdaInterfaceMoved(3) and pmdaText(3).

COLOPHON         top

       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
       2025-02-02.  (At that time, the date of the most recent commit
       that was found in the repository was 2025-01-30.)  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                         PMDADSO(3)

Pages that refer to this page: pmda(3)pmdaattribute(3)pmdachildren(3)pmdadaemon(3)pmdadesc(3)pmdafetch(3)pmdagetoptions(3)pmdahelp(3)pmdainit(3)pmdainstance(3)pmdainterfacemoved(3)pmdalabel(3)pmdaname(3)pmdaopenlog(3)pmdapmid(3)pmdaprofile(3)pmdastore(3)pmdatext(3)