NAME

       pmUnpackEventRecords, pmUnpackHighResEventRecords - unpack event records

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmUnpackEventRecords(pmValueSet *vsp, int idx, pmResult ***rap);

       int pmUnpackHighResEventRecords(pmValueSet *vsp, int idx, pmHighResResult ***hrap);

       cc ... -lpcp

DESCRIPTION

       Event  records are encoded as a packed array of records within a pmResult using a container metric with a
       value of type PM_TYPE_EVENT , and a pmHighResResult when using a metric of type PM_TYPE_HIGHRES_EVENT.

       pmUnpackEventRecords and pmUnpackHighResEventRecords may be used to unpack event records  from  a  metric
       value  identified  by vsp and idx.  If the metric has a singular value, idx should be 0, else the ordinal
       instance value identified by idx will be unpacked, i.e. vsp->vlist[idx].  The unpacked records are turned
       into either pmResult or pmHighResResult structures, one  per  event  record  and  one  metric  per  event
       parameter,  and  rap  is  returned  as a pointer to an array (NULL pointer terminated) of pointers to the
       result structures.

       The only difference between the two result types is the timestamp scale; the pmHighResResult  allows  for
       nanosecond precision, whereas pmResult allows for microsecond resolution.

       Some  control information from the packed event records is unpacked into additional ``anonymous'' metrics
       as follows:

       1.  If the event record has a non-zero flags value, then the corresponding pmResult/pmHighResResult  will
           have  the  flags  value  encoded with the additional metric event.flags that is inserted ahead of all
           other event parameters.

       2.  If   the   event   record   flag   is   set   to   PM_EVENT_FLAG_MISSED,   then   the   corresponding
           pmResult/pmHighResResult  will  have  one  metric event.missed with a value that equals the number of
           event records ``missed'' because either the PMDA could not keep up,  or  the  PMAPI  client  did  not
           collect the event records fast enough.

       pmUnpackEventRecords  returns  the  number  of pmResult structures as the return value, which is >= 0 for
       success.  Similarly, pmUnpackHighResEventRecords returns the number of pmHighResResult structures as  the
       return value, which is >= 0 for success.

       rap   and   the   associated   pmResult   structures   may   be  freed  using  the  convenience  function
       pmFreeEventResult(3).

       Similarly, the hrap and the associated pmHighResResult structures may  be  freed  using  the  convenience
       function pmFreeHighResEventResult.

RETURN VALUE

       The following errors are possible:

       PM_ERR_CONV
                 The  values associated with vsp are not encoded using the format PM_VAL_DPTR or PM_VAL_SPTR, or
                 the flags at the head of the event record has an unexpected value.

       PM_ERR_INST
                 The value associated with vsp is not singular as expected.

       PM_ERR_TYPE
                 vsp is not a value of type PM_TYPE_EVENT.

       PM_ERR_TOOSMALL
                 The value identified by vbp is not legal because the value length  is  less  than  the  minimum
                 size,    or    the    number    of    event    records    encoded   in   the   (value   header)
                 pmEventArray/pmEventHighResArray structure is negative, or the number of missed  event  records
                 in the array is negative.

       PM_ERR_TOOBIG
                 Either  vsp  indicates more than one value is present (all the event records are expected to be
                 packed in a single metric value), or when unpacking the event records, the processing continues
                 past the end of the enclosing value.  Indicates corruption of the packed event record.

       PM_ERR_TYPE
                 Event parameters must have one of the arithmetic types, else PM_TYPE_AGGREGATE,  PM_TYPE_STRING
                 or PM_TYPE_AGGREGATE_STATIC.

       other values < 0
                 refer to pmErrStr(3).

SEE ALSO

       PMAPI(3) and pmFreeEventResult(3).

Performance Co-Pilot                                   PCP                               PMUNPACKEVENTRECORDS(3)