NAME

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

C SYNOPSIS

       #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

       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

       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.

DIAGNOSTICS AND RETURN VALUES

       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

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