plucky (3) pmdaDSO.3.gz

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).