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 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.

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).