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NAME | C SYNOPSIS | CAVEAT | DESCRIPTION | DIAGNOSTICS AND RETURN VALUES | SEE ALSO | COLOPHON |
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PMATRYDELTAINDOM(3) Library Functions Manual PMATRYDELTAINDOM(3)
pmaTryDeltaInDom - try to translate a physical indom record from a
``full indom'' to a ``delta indom''
#include <pcp/pmapi.h>
#include <pcp/libpcp.h>
#include <pcp/archive.h>
int pmaTryDeltaInDom(__pmLogCtl *lcp, __int32_t **rbuf,
__pmLogInDom *lidp);
cc ... -lpcp_archive -lpcp
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.
The input instance domain is passed in as either a physical meta‐
data record via rbuf or in the ``loaded'' format identified by
lidp. As these are alternate formats for the input instance do‐
main, pmaTryDeltaInDom demands that exactly one of rbuf and lidp
must be NULL, else the return value is -2.
The input instance domain is on the path to being written to the
archive identified by lcp.
If possible, the instance domain will be converted to the ``delta
indom'' format, and the converted instance domain returned via
rbuf or lidp (whichever is not NULL). If conversion takes place,
any storage associated with the input instance domain will have
been free'd.
The ``delta indom'' format is only supported for Version 3
archives and it is the caller's responsibility to determine if
calling pmaTryDeltaInDom is appropriate.
To determine if the ``delta indom'' format is the most efficient
encoding, pmaTryDeltaInDom maintains a per-instance domain cache
of the last seen ``full'' instance domain. To avoid data corrup‐
tion, this means pmaTryDeltaInDom first copies the input instance
domain. The copy and the cache are all managed privately by pma‐
TryDeltaInDom so the caller is unaware of this activity.
The caching scheme requires that the caller must call pmaTry‐
DeltaInDom for every instance domain record, independent of
whether the ``delta indom'' format is likely to be appropriate.
In several places, fatal errors will trigger an error message and
force the application to exit.
A return value of -1 indicates that rbuf was not NULL and the
physical record therein was not a TYPE_INDOM (Version 3 ``full''
instance domain) record as expected. A return value of 1 means
rbuf or lidp has been rewritten, and is now a TYPE_INDOM_DELTA
record. Otherwise the return value is 0.
pmaDeltaInDom(3), PMAPI(3) and pmaUndeltaInDom(3).
This page is part of the PCP (Performance Co-Pilot) project. In‐
formation about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
pcp@groups.io. This page was obtained from the project's upstream
Git repository ⟨https://github.com/performancecopilot/pcp.git⟩ on
2025-08-11. (At that time, the date of the most recent commit
that was found in the repository was 2025-08-11.) If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a
mail to man-pages@man7.org
Performance Co-Pilot PCP PMATRYDELTAINDOM(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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