pmarewritedata(3) — Linux manual page


PMAREWRITEDATA(3)       Library Functions Manual       PMAREWRITEDATA(3)

NAME         top

       pmaRewriteData - try to change the version of an archive data

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
       equivalent 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
       responsibility 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.


       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
       return 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.
       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 2023-12-22.
       (At that time, the date of the most recent commit that was found
       in the repository was 2023-12-16.)  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               PCP                 PMAREWRITEDATA(3)

Pages that refer to this page: pmarewritemeta(3)