---
name: "pmaRewriteData"
section: "3"
platform: "linux"
package: "pcp"
version: "7.2.2-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/pmaRewriteData"
---

# pmaRewriteData(3)

try to change the version of an archive data record

## 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)](/malloc/3.md). 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)](/free/3.md), [**malloc**(3)](/malloc/3.md), [**PMAPI**(3)](/PMAPI/3.md), and [**pmaRewriteMeta**(3)](/pmaRewriteMeta/3.md).