NAME

       pmaRewriteMeta - try to change the version of an archive metadata record

C SYNOPSIS

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

       int pmaRewriteMeta(__pmLogCtl *inlcp, __pmLogCtl *outlcp, __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  metadata  record  from the input archive identified by inlcp is passed in via
       rbuf and this is reformatted if required to produce the equivalent metadata record for the
       output archive identified by outlcp.

       Combined  with  the input and output archive versions, the type of the metadata record (as
       extracted from rbuf) is used to decide if; for some record types and  version  changes  no
       rewriting is required.

       pmaRewriteMeta  is  intended  to  be  used in cases where the archive version of inlcp and
       outlcp are differerent.  The only sane choice of archive versions today  is  PM_LOG_VERS02
       for  inlcp  and PM_LOG_VERS03 for outlcp, 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  for  the  versions  of  inlcp  and  outlcp  then
       pmaRewriteMeta 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 pmaRewriteData(3).