NAME

       pmLookupName - translate performance metric names into PMIDs

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmLookupName(int numpmid, 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 5
       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 ... */
           ...
       }

SEE ALSO

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

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.