pmarewritedata(3) — Linux manual page

NAME | C SYNOPSIS | CAVEAT | DESCRIPTION | DIAGNOSTICS AND RETURN VALUES | SEE ALSO | COLOPHON

PMAREWRITEDATA(3)        Library Functions Manual       PMAREWRITEDATA(3)

NAME         top

       pmaRewriteData - try to change the version of an archive data
       record

C SYNOPSIS         top

       #include <pcp/pmapi.h>
       #include <pcp/libpcp.h>
       #include <pcp/archive.h>

       int pmaRewriteData(int invers, int outvers __int32_t *rbuf);

       cc ... -lpcp_archive -lpcp

CAVEAT         top

       This  documentation  is intended for internal Performance Co-Pilot
       (PCP) developer use.

       These interfaces are not part of the PCP APIs that are  guaranteed
       to  remain  fixed  across  releases, and they may not work, or may
       provide different semantics at some point in the future.

DESCRIPTION         top

       A physical data record from a version invers archive is passed  in
       via rbuf and this is reformatted if required to produce the equiv‐
       alent data record for a version outvers archive.

       Archive  data  records  provide  the encoding of a pmResult for an
       archive data volume.

       The only sane choice of invers and outvers today is  PM_LOG_VERS02
       and  PM_LOG_VERS03  respectively,  which  would  be  requesting  a
       rewrite from archive version 2 format to archive version 3  format
       (as only versions 2 and 3 are currently supported).

       If  rewriting takes place the old rbuf will have been free'd and a
       new rbuf allocated with malloc(3).  It is the  caller's  responsi‐
       bility to make sure this potential free-and-allocate will be safe,
       e.g.  no dangling references into the contents of rbuf, or pass in
       a copy of the record if it is precious.

DIAGNOSTICS AND RETURN VALUES         top

       In several places, fatal errors will trigger an error message  and
       force the application to exit.

       If  there  is  no  defined translation from invers to outvers then
       pmaRewriteData returns PM_ERR_APPVERSION (a slight  perversion  of
       this error code).

       If no rewrite is performed, the return value is 0, otherwise a re‐
       turn  value  of 1 indicates a rewrite has taken place and rbuf has
       been reallocated.

SEE ALSO         top

       free(3), malloc(3), PMAPI(3), and pmaRewriteMeta(3).

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.   In‐
       formation  about the project can be found at ⟨http://www.pcp.io/⟩.
       If you have a  bug  report  for  this  manual  page,  send  it  to
       pcp@groups.io.  This page was obtained from the project's upstream
       Git  repository ⟨https://github.com/performancecopilot/pcp.git⟩ on
       2025-08-11.  (At that time, the date of  the  most  recent  commit
       that was found in the repository was 2025-08-11.)  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 man-pages@man7.org

Performance Co-Pilot               PCP                  PMAREWRITEDATA(3)

Pages that refer to this page: pmarewritemeta(3)