HUMANIZE_NUMBER(3)

HUMANIZE_NUMBER(3) | Library Functions Manual | HUMANIZE_NUMBER(3)

# NAME

dehumanize_number, humanize_number — format a number into a human readable form and vice versa

# SYNOPSIS

#include <stdlib.h>

int
dehumanize_number(const char *str, int64_t *result);

int
humanize_number(char *buffer, size_t len, int64_t number, const char *suffix, int scale, int flags);

# DESCRIPTION

The humanize_number() function formats the signed 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 1024 until it will. In this case, prefix suffix with the appropriate SI designator.

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. To use a specific prefix, specify this as scale (Multiplier = 1024 ^ scale). This can not be combined with any of the scale flags below.

The following flags may be passed in scale:

HN_AUTOSCALE
  Format the buffer using the lowest multiplier possible.
HN_GETSCALE
  Return the prefix index number (the number of times number must be divided to fit) instead of formatting it to the buffer.

The following flags may be passed in flags:

HN_DECIMAL
  If the final result is less than 10, display it using one digit.
HN_NOSPACE
  Do not put a space between number and the prefix.
HN_B
  Use 'B' (bytes) as prefix if the original result does not have a prefix.
HN_DIVISOR_1000
  Divide number with 1000 instead of 1024.

The dehumanize_number() function parses the string representing an integral value given in str and stores the numerical value in the integer pointed to by result. The provided string may hold one of the suffixes, which will be interpreted and used to scale up its accompanying numerical value.

# RETURN VALUES

humanize_number() returns the number of characters stored in buffer (excluding the terminating NUL) upon success, or -1 upon failure. If HN_GETSCALE is specified, the prefix index number will be returned instead.

dehumanize_number() returns 0 if the string was parsed correctly. A -1 is returned to indicate failure and an error code is stored in errno.

# ERRORS

dehumanize_number() will fail and no number will be stored in result if:

[EINVAL]
  The string in str was empty or carried an unknown suffix.
[ERANGE]
  The string in str represented a number that does not fit in result.

# SEE ALSO

strsuftoll(3), orders(7), humanize_number(9)

# HISTORY

humanize_number() first appeared in NetBSD 2.0.

dehumanize_number() first appeared in NetBSD 5.0.

January 14, 2011 | NetBSD 7.1