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NAME | C++ SYNOPSIS | DESCRIPTION | CONSTRUCTORS | DESCRIPTOR LOOKUP | DIAGNOSTICS | SEE ALSO | COLOPHON |
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QMCCONTEXT(3) Library Functions Manual QMCCONTEXT(3)
QmcContext - container for a PMAPI context and its metrics
#include <QmcContext.h>
c++ ... -lpcp_qmc -lpcp
A QmcContext object is a container for a single PMAPI(3) context.
The object maintains a list of all the metric descriptors (QmcDe‐
sc), instance domains (QmcIndom) and metrics (QmcMetric) using the
context to minimize the duplication of these objects.
A QmcContext object should be constructed through the Qmc‐
Group::use interface.
The metric and instance domain descriptors are cached by the Qmc‐
Context object to reduce duplicate QmcDesc(3) and QmcIndom(3) ob‐
jects and PMAPI(3) calls required to create them. Also the map‐
ping from metrics names to pmIDs is also maintained to avoid
pmLookupName(3) calls.
int lookupDesc(const char *name, pmID& id);
Search for the metric name in the name list and set id to the
known pmID. If not found, use pmLookupName(3) to get the map‐
ping. If this call fails, the PMAPI(3) error code will be re‐
turned.
int lookupDesc(const char *name, uint_t& desc, uint_t& indom);
Find the index desc and indom to the QmcDesc object and the
QmcIndom object for the metric name. The indexes can then be
used with QmcContext::desc and QmcContext::indom to obtain
references to the real objects. The methods will return a
PMAPI(3) error code if the metric descriptor or instance do‐
main could not be obtained.
int lookupDesc(pmID pmid, uint_t& desc, uint_t& indom);
Find the index desc and indom to the QmcDesc object and the
QmcIndom object for the metric pmid. The indexes can then be
used with QmcContext::desc and QmcContext::indom to obtain
references to the real objects. The methods will return a
PMAPI(3) error code if the metric descriptor or instance do‐
main could not be obtained.
Error messages are generated using pmprintf(3) but are not
flushed. It is the responsibility of the user to call pmflush(3)
to output any messages.
Additional diagnostics may be activated by adding the options pmc
and/or optfetch to the global debugging specification, as de‐
scribed in pmSetDebug(3).
PMAPI(3), QMC(3), QmcDesc(3), QmcGroup(3), QmcIndom(3),
QmcMetric(3), pmflush(3), pmLookupName(3) and pmprintf(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 SGI QMCCONTEXT(3)
Pages that refer to this page: QMC(3), QmcGroup(3), QmcIndom(3), QmcMetric(3), QmcSource(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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