pmNumberStr man page

pmNumberStr, pmNumberStr_r — fixed width output format for numbers

C Synopsis

#include <pcp/pmapi.h>

const char *pmNumberStr(double value);
char *pmNumberStr_r(double value, char *buf, int buflen);

cc ... -lpcp

Description

pmNumberStr returns the address of a 8-byte buffer that holds a null-byte terminated representation of value suitable for output with fixed width fields. The pmNumberStr_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 8 bytes.

The value is scaled using multipliers in powers of “one thousand” (the decimal “kilo”) and has a bias that provides greater precision for positive numbers as opposed to negative numbers.

The format depends on the sign and magnitude of value as follows (d represents a decimal digit):

value range format
       > 999995000000000 inf?
999995000000000 - 999995000000 ddd.ddT
  999995000000 - 999995000 ddd.ddG
     999995000 - 999995 ddd.ddM
        999995 - 999.995 ddd.ddK
       999.995 - 0.005 ddd.dd
         0.005 - -0.005  0.00
        -0.005 - -99.95 -dd.dd
       -99.995 - -99995 -dd.ddK
        -99995 - -99995000 -dd.ddM
     -99995000 - -99995000000 -dd.ddG
  -99995000000 - -99995000000000 -dd.ddT
      < -99995000000000 -inf?

At the boundary points of the ranges, the chosen format will retain the maximum number of significant digits.

Notes

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

See Also

printf(3)

Info

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