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NAME | C SYNOPSIS | DESCRIPTION | NOTES | SEE ALSO | COLOPHON |
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PMUNITSSTR(3) Library Functions Manual PMUNITSSTR(3)
pmUnitsStr, pmUnitsStr_r - convert a performance metric's units
into a string
#include <pcp/pmapi.h>
const char *pmUnitsStr(const pmUnits *pu);
char *pmUnitsStr_r(const pmUnits *pu, char *buf, int buflen);
cc ... -lpcp
The encoding of a performance metric's dimensionality and scale
uses a pmUnits structure; see pmLookupDesc(3).
As an aid to labeling graphs and tables, or for error messages,
pmUnitsStr will take a dimension and scale specification as per
pu, and return the corresponding text string. The pmUnitsStr_r
function does the same, but stores the result in a user-supplied
buffer buf of length buflen, which should have room for at least
60 bytes. If buflen is less than 60 then pmUnitsStr_r returns
NULL and buf is not changed.
For example {1, -2, 0, PM_SPACE_MBYTE, PM_TIME_SEC, 0}, as the
value of *pu gives the result string Mbyte / sec^2.
The string value result from pmUnitsStr is held in a single static
buffer, so the returned value is only valid until the next call to
pmUnitsStr.
If the ``count'' dimension is non-zero, and the ``count'' scale is
not zero, then the text string will include a decimal scaling fac‐
tor, e.g. count x 10^6.
As a special case, if all components of the dimension are zero,
then the ``count'' scale is used to produce the text. If this
scale is zero the result is an empty string, otherwise the result
is of the form x1 0^2.
pmUnitsStr returns a pointer to a static buffer and hence is not
thread-safe. Multi-threaded applications should use pmUnitsStr_r
instead.
PMAPI(3), pmAtomStr(3), pmConvScale(3), pmExtractValue(3),
pmLookupDesc(3), pmPrintValue(3), pmIDStr(3), pmInDomStr(3),
pmTypeStr(3), pmSemStr(3) and pmUnitsStr(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 PMUNITSSTR(3)
Pages that refer to this page: pmlogsummary(1), pmatomstr(3), pmconvscale(3), pmextractvalue(3), pmidstr(3), pmindomstr(3), pmlookupdesc(3), pmparseunitsstr(3), pmprintvalue(3), pmsemstr(3), pmtypestr(3), pmunitsstr(3), pmwebapi(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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