PMNUMBERSTR(3) Library Functions Manual PMNUMBERSTR(3)

pmNumberStr, pmNumberStr_r - fixed width output format for numbers

#include <pcp/pmapi.h>

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

cc ... -lpcp

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.

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


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