NAME

       pmdaDSO - initialize the PMDA to run as a DSO

C SYNOPSIS

       #include <pcp/pmapi.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 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) configu‐
       ration file. The domain is used to initialize the metric and instance descriptors (see pmdaInit(3)).

CAVEAT

       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 otherwise re‐
       leased, 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 pmdaIn‐
       terface structure at the new location before any other routine in libpcp_pmda is called.

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 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

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

Performance Co-Pilot                                   PCP                                            PMDADSO(3)