NAME

       pmParseUnitsStr - parse time point specification

C SYNOPSIS

       #include <pcp/pmapi.h>

       int pmParseUnitsStr(const char *string, struct pmUnits *out, double *outMult, char **errMsg);

       cc ... -lpcp

DESCRIPTION

       pmParseUnitsStr  is  designed  to encapsulate the interpretation of a unit/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  con‐
       versions 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.

EXAMPLES

                           ┌───────────────────────────────────┬────────────────┬─────────┐
                           │              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       │
                           └───────────────────────────────────┴────────────────┴─────────┘

RETURN VALUE

       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().

SEE ALSO

       PMAPI(3), pmUnitsStr(3), pmConvScale(3), and pmLookupDesc(3).

Performance Co-Pilot                                   PCP                                    PMPARSEUNITSSTR(3)