HUMANIZE_NUMBER(9)

NAME
humanize_number, format_bytes - format a number into a human readable form

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

  humanize_number
The humanize_number() function formats the unsigned 64 bit quantity given in number into buffer. A space and then suffix is appended to the end. buffer must be at least len bytes long.

If the formatted number (including suffix) would be too long to fit into buffer, then divide number by divisor until it will. In this case, prefix suffix 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

len must be at least 4 plus the length of suffix, in order to ensure a useful result is generated into buffer.

  format_bytes
The format_bytes() function is a front-end to humanize_number() that calls the latter with a suffix of “B”. Also, if the suffix in the returned buffer would not have a prefix, remove the suffix. This means that a result of “100000” occurs, instead of “100000 B”.

RETURN VALUES
humanize_number() and format_bytes() return the number of characters stored in buffer (excluding the terminating NUL) upon success, or -1 upon failure.

HISTORY
humanize_number() and format_bytes() first appeared in NetBSD 1.5.