NAME
humanize_number,
format_bytes —
human readable numbers
SYNOPSIS
int
humanize_number(char
*buf, size_t len,
uint64_t number,
const char *suffix,
int divisor);
int
format_bytes(char
*buf, size_t len,
uint64_t number);
DESCRIPTION
Thehumanize_number()
function formats the unsigned 64-bit quantity given in
number into buf. A space and then
suffix is appended to the end. The supplied
buf must be at least len bytes
long.
If the formatted number (including
suffix) is too long to fit into
buf,
humanize_number()
divides number by divisor until
it will fit. In this case, suffix is prefixed with the
appropriate SI designator. Suitable values of divisor
are 1024 or 1000 to remain consistent with the common meanings of the SI
designator prefixes.
The prefixes are:
| Prefix | Description | Multiplier |
| k | kilo | 1024 |
| M | mega | 1048576 |
| G | giga | 1073741824 |
| T | tera | 1099511627776 |
| P | peta | 1125899906842624 |
| E | exa | 1152921504606846976 |
The len argument must be at least 4 plus the length of suffix, in order to ensure a useful result in buf.
The
format_bytes()
function is a front-end to humanize_number(). It
calls the latter with a suffix of “B”.
Also, if the suffix in the returned buf would not have
a prefix, the suffix is removed. This means that a result of
“100000” occurs, instead of “100000 B”.
RETURN VALUES
Both functions return the number of characters stored in buf (excluding the terminating NUL) upon success, or -1 upon failure.
SEE ALSO
HISTORY
These functions first appeared in NetBSD 1.5.