NAME

       pmLookupName - translate performance metric names into PMIDs

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmLookupName(int numpmid, const char **namelist, pmID *pmidlist);

       cc ... -lpcp

DESCRIPTION

       Given  a  list  in  namelist containing numpmid full pathnames for performance metrics from a Performance
       Metrics Name Space (PMNS), pmLookupName returns the list of  associated  Performance  Metric  Identifiers
       (PMIDs) via pmidlist.

       The  result  from  pmLookupName  depends  on  the presence of any lookup failures, their severity and the
       number of metrics being looked up.

       1.  If there are no lookup failures, the return value will be numpmid.

       2.  If a fatal error is encountered, the return value will be less than 0.  For example  PM_ERR_TOOSMALL,
           PM_ERR_NOPMNS or PM_ERR_IPC.

       3.  If numpmid is greater than one and non-fatal error(s) are encountered, the return value is the number
           of metric names that have successfully been looked up (greater than or equal to zero and less than or
           equal to numpmid).

       4.  If numpmid is one and a non-fatal error is encountered, the return value is the error code (less than
           zero).

       When errors are encountered, any metrics that cannot be looked up result in the corresponding element  of
       pmidlist being set to PM_ID_NULL.

       The  slightly  convoluted  error protocol allows bulk lookups, then probing for more error details in the
       case of a specific failure, as shown in the EXAMPLES section below.

       Note that the error protocol guarantees there is a 1:1 relationship between the elements of namelist  and
       pmidlist,  hence both lists contain exactly numpmid elements.  For this reason, the caller is expected to
       have pre-allocated a suitably sized array for pmidlist.

EXAMPLE

       #include <pcp/pmapi.h>

       #define NUMPMID (sizeof(names)/sizeof(const char *))
       const char *names[] = {
                      "sample.bin",
                      "sample",
                      "sample.bog",
                      "sample.secret.bar",
                      "sample.secret.bar.bad"
                    };
       pmID pmids[NUMPMID];

       int
       main(int argc, char **argv)
       {
           int   sts;
           int   numpmid = NUMPMID;

           pmNewContext(PM_CONTEXT_HOST, "local:");

           sts = pmLookupName(numpmid, names, pmids);

           if (sts < 0) {
            fprintf(stderr, "pmLookupName failed: %s0, pmErrStr(sts));
            exit(1);
           }
           if (sts != numpmid) {
            /*
             * some of the lookups failed ... report the reason(s)
             */
            int  i;

            for (i = 0; i < numpmid; i++) {
                if (pmids[i] != PM_ID_NULL) continue;
                /* this one failed */
                sts = pmLookupName(1, &names[i], &pmids[i]);
                fprintf(stderr, "%s: lookup failed: %s0, names[i], pmErrStr(sts));
            }
            exit(1);
           }

           /* all good ... */
           ...
       }

DIAGNOSTICS

       PM_ERR_TOOSMALL
              numpmid must be at least 1

       PM_ERR_NOPMNS
              Failed to access a PMNS for operation.  Note that  if  the  application  hasn't  a  priori  called
              pmLoadNameSpace(3) and wants to use the distributed PMNS, then a call to pmLookupName must be made
              after the creation of a context (see pmNewContext(3)).

       PM_ERR_NAME
              namelist[0] does not correspond to a valid metric name in the PMNS.

       PM_ERR_NONLEAF
              namelist[0] refers to a node in the PMNS but it was not a leaf node.

       PM_ERR_*
              Other diagnostics are for protocol failures when accessing the distributed PMNS.

SEE ALSO

       PMAPI(3),  pmGetChildren(3),  pmGetChildrenStatus(3),  pmGetConfig(3),  pmLoadNameSpace(3),  pmNameID(3),
       pmNewContext(3), pcp.conf(5) and pcp.env(5).