PMAREWRITEDATA(3)

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).