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pmatomstr(3) — Linux manual page

PMATOMSTR(3) Library Functions Manual PMATOMSTR(3)

NAME top

 pmAtomStr, pmAtomStr_r - convert a performance metric value into a
 string

C SYNOPSIS top

 #include <pcp/pmapi.h>
 const char *pmAtomStr(const pmAtomValue *avp, int type);
 char *pmAtomStr_r(const pmAtomValue *avp, int type, char *buf,
 int buflen);
 cc ... -lpcp

DESCRIPTION top

 All performance metric values may be encoded in a pmAtomValue
 union, defined as follows;
 typedef union {
 __int32_t l; /* 32-bit signed */
 __uint32_t ul; /* 32-bit unsigned */
 __int64_t ll; /* 64-bit signed */
 __uint64_t ull; /* 64-bit unsigned */
 float f; /* 32-bit floating point */
 double d; /* 64-bit floating point */
 char *cp; /* char ptr */
 pmValueBlock *vbp; /* pmValueBlock ptr */
 } pmAtomValue;
 Given the performance metric value pointed to by avp, and a per‐
 formance metric type defined by type, pmAtomStr will generate the
 corresponding metric value as a string, suitable for diagnostic or
 report output. The pmAtomStr_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 80 bytes.
 The value for type is typically extracted from a pmDesc structure,
 following a call to pmLookupDesc(3) for a particular performance
 metric.
 If the type is PM_TYPE_STRING values longer than 38 characters
 will be truncated after 34 characters, and truncation shown with
 ellipsis ``...'' at the end of the value.
 If the type is PM_TYPE_AGGREGATE then up to the first three 32-bit
 words are displayed as hexadecimal values.
 If the type is PM_TYPE_EVENT then a summary of the number of event
 records found in the value is generated.
 The return value from pmAtomStr is held in a single static buffer,
 so the returned value is only valid until the next call to pmAtom‐
 Str.

NOTES top

 pmAtomStr returns a pointer to a static buffer and hence is not
 thread-safe. Multi-threaded applications should use pmAtomStr_r
 instead.

SEE ALSO top

 PMAPI(3), pmConvScale(3), pmExtractValue(3), pmLookupDesc(3),
 pmPrintValue(3), pmTypeStr(3) and pmUnitsStr(3).

COLOPHON top

 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年08月11日. (At that time, the date of the most recent commit
 that was found in the repository was 2025年08月11日.) 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 PMATOMSTR(3)

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Pages that refer to this page: pmconvscale(3), pmextractvalue(3), pmlookupdesc(3), pmprintvalue(3), pmsemstr(3), pmtypestr(3), pmunitsstr(3)

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