pmdadso(3) — Linux manual page


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 interface
       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

DIAGNOSTICS         top

       Incompatible version of pmcd detected
                      When pmcd(1) creates the pmdaInterface structure, the
                      dispatch.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.

CAVEAT         top

       The PMDA must be using PMDA_INTERFACE_2 or later.

       Once pmdaDSO has been called, it is expected that the pmdaInterface
       structure pointed to by dispatch will remain accessible to the
       routines in libpcp_pmda (not reclaimed off the stack, not freed or
       oherwise 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 resestablish the internal
       integrity of the pmdaInterface structure at the new location before
       any other routine in libpcp_pmda is called.

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.
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Performance Co-Pilot                 PCP                          PMDADSO(3)