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 released 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 af‐
       ter the move pmdaInterfaceMoved(3) must be called to re-establish
       the internal integrity of the pmdaInterface structure at the new
       location 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 2024-06-14.
       (At that time, the date of the most recent commit that was found
       in the repository was 2024-06-14.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
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       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)