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pmparseunitsstr(3)

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).



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