pmspeclocalpmda(3) — Linux manual page


PMSPECLOCALPMDA(3)      Library Functions Manual      PMSPECLOCALPMDA(3)

NAME         top

       pmSpecLocalPMDA - process command-line argument for the table of
       DSO PMDAs

C SYNOPSIS         top

       #include "pmapi.h"
       #include "libpcp.h"

       char *pmSpecLocalPMDA(const char *spec);

       cc ... -lpcp

DESCRIPTION         top

       For Performance Co-Pilot (PCP) applications, contexts of type
       PM_CONTEXT_LOCAL are used by clients that wish to fetch metrics
       directly from one or more PMDAs on the local host without
       involving pmcd(1).

       pmSpecLocalPMDA provides a convenience wrapper to be used by
       applications that wish to use a command line argument (usually
       with -K) to control the DSO PMDAs that are available for a
       PM_CONTEXT_LOCAL context.

       The spec argument specifies actions for one or more DSO PMDAs
       using up to four fields separated by commas (``,''), namely:
       -      an opcode with one of the values add (add a new entry),
              del (delete an existing entry) or clear (clear all entries
              from the table).
       -      the PMDA's domain number
       -      the path to the PMDA DSO (may be absolute or relative to
              the $PCP_VAR_DIR/pmdas directory and the DSO suffix is
              optional), and
       -      the name of the PMDA's initialization routine.

       All fields are required to add a new entry.  To delete an entry
       the opcode is required plus either or both of the domain number
       and path fields.  To clear all entries, only the opcode is

       If spec is parsed successfully, then the DSO table is updated
       with the extracted fields.

RETURN VALUE         top

       On success, pmSpecLocalPMDA will return NULL.

       On error or failure, pmSpecLocalPMDA will return a pointer to a
       static error message.

EXAMPLES         top

       Some examples of valid spec strings:

       clear  Delete all entries from the DSO table.

              Add the ``foo'' PMDA using domain 123.  The PMDA's DSO is
              most likely in below the directory $PCP_PMDAS_DIR and
              named foo/ (for ELF-style platforms) or
              foo/foo_pmda.dylib (for BSD-style platforms) or
              foo\foo_pmda.dll (for Windows-style platforms).  The
              initialization routine for the ``foo'' PMDA is foo_init().

              Delete the entry for the DSO with domain 123.

              Delete the entry with a pathname to the DSO that matches

              Delete the entry for the DSO with either domain 123 and/or
              a pathname to the DSO that matches foo/foo_pmda.

SEE ALSO         top

       pmcd(1), PMAPI(3) and pmNewContext(3).

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 2024-06-14.
       (At that time, the date of the most recent commit that was found
       in the repository was 2024-06-14.)  If you discover any rendering
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       (which is not part of the original manual page), send a mail to

Performance Co-Pilot                                  PMSPECLOCALPMDA(3)

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