pmlookupname(3) — Linux manual page


PMLOOKUPNAME(3)           Library Functions Manual           PMLOOKUPNAME(3)

NAME         top

       pmLookupName - translate performance metric names into PMIDs

C SYNOPSIS         top

       #include <pcp/pmapi.h>

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

       cc ... -lpcp

DESCRIPTION         top

       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

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

       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

       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         top

       #include <pcp/pmapi.h>

       #define NUMPMID 5
       char      *names[] = { "sample.bin",
       pmID pmids[NUMPMID];

       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));
           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));

           /* all good ... */

SEE ALSO         top

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

DIAGNOSTICS         top

              numpmid must be at least 1

              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

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

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

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

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.
       Information about the project can be found at ⟨⟩.
       If you have a bug report for this manual page, send it to  This page was obtained from the project's upstream
       Git repository ⟨⟩ on
       2020-08-13.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-08-11.)  If you discover any
       rendering problems in this HTML version of the page, or you believe
       there is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

Performance Co-Pilot                 PCP                     PMLOOKUPNAME(3)