humanize_number.3bsd - Man Page

format a number into a human readable form and viceversa

Library

library “libbsd”

Synopsis

#include <stdlib.h> (See libbsd(7) for include usage.)
int
dehumanize_number(const char *str, int64_t *result);

int
humanize_number(char *buf, 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:

PrefixDescriptionMultiplier
kkilo1024
Mmega1048576
Ggiga1073741824
Ttera1099511627776
Ppeta1125899906842624
Eexa1152921504606846976

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

humanize_number(9)

History

humanize_number() first appeared in NetBSD 2.0.

dehumanize_number() first appeared in NetBSD 5.0.

Referenced By

The man page dehumanize_number.3bsd(3) is an alias of humanize_number.3bsd(3).

February 9, 2008