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NAME | C SYNOPSIS | DESCRIPTION | EXAMPLES | RETURN VALUE | SEE ALSO | COLOPHON |
PMPARSEUNITSSTR(3) Library Functions Manual PMPARSEUNITSSTR(3)
pmParseUnitsStr - parse units specification
#include <pcp/pmapi.h>
int pmParseUnitsStr(const char *string, struct pmUnits *out,
double *outMult, char **errMsg);
cc ... -lpcp
pmParseUnitsStr is designed to encapsulate the interpretation of a
units (dimension and scale) specification in command line switches
for use by the PCP client tools.
This function expects to be called with the unit/scale specification
as string. This specification takes the general form produced by
pmUnitsStr. Briefly, the format allows /-separated divisor and
dividend, each listing space-separated dimensions/scales along the
space, time, and count axes. There are also a few extra
possibilities:
First, multiple equivalent sets of keywords are accepted for the time
& space dimensions, insensitive to case. For example,
"microseconds", "microsecond", "microsec", "us" are considered
synonymous, as are "kilobytes", "KB", "kiloByte", and so on.
Second, units may be offered in any order, e.g., ms kb count x 10^3
or count x 10^3 kb ms. They may not be repeated within the
denominator or within the numerator. Each scale/unit keyword may be
immediately followed by positive or negative exponents, e.g., ^-4.
Third, numerical scaling factors may be supplied. These are factored
together with implicit scale conversions into the final outMult
result.
The out and outMult values must both be allocated before calling
pmParseUnitsStr. If the conversion is successful, pmParseUnitsStr
returns 0, and fills in out and outMult with the unit/scales defined
by the input parameter. If the argument strings could not be parsed,
it returns a negative status code.
┌──────────────────────────────────┬────────────────┬─────────┐
│ string │ out │ outMult │
├──────────────────────────────────┼────────────────┼─────────┤
│2 count │ {0,1,0,0,0,0} │ 0.5 │
│count / 7.5 nanosecond │ {0,1,-1,0,0,0} │ 7.5 │
│10 kilobytes / 2.5e2 count x 10^3 │ {1,-1,0,1,3,0} │ 25 │
│millisecond / second^2 │ {0,0,-1,0,0,3} │ 1000 │
│mb/s │ {1,0,-1,2,0,3} │ 1 │
└──────────────────────────────────┴────────────────┴─────────┘
A zero status indicates success. A negative status indicates an
error, in which case the errMsg pointer will receive a textual error
message, which the caller should later free().
PMAPI(3), pmUnitsStr(3), pmConvScale(3), and pmLookupDesc(3).
This page is part of the PCP (Performance Co-Pilot) project.
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Performance Co-Pilot PCP PMPARSEUNITSSTR(3)
Pages that refer to this page: pcp2graphite(1), pcp2influxdb(1), pmdaprometheus(1), pmrep(1), pmfetchgroup(3), pmregisterderived(3)