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)  configuration  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 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
       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).