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HUMANIZE_NUMBER(3) NetBSD Library Functions Manual HUMANIZE_NUMBER(3)
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by Kimmo Suominen.
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dehumanize_number, humanize_number -- format a number into a human read-
able form and vice versa
dehumanize_number(const char *str, int64_t *result);
humanize_number(char *buffer, size_t len, int64_t number,
const char *suffix, int scale, int flags);
The humanize_number() function formats the signed 64 bit quantity given
in number into buffer. A space and then the suffix (if not null) is
appended to the end. len gives the size of the buffer.
If the formatted number (including suffix) would be too long to fit into
buffer, then repeatedly divide number by 1024 until it will fit. 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, spec-
ify this as scale (Multiplier = 1024 ^ scale). The scale must be at
least 0 and no more than 6.
Alternatively, one of the following special values may be given as scale:
HN_AUTOSCALE Format the buffer using the lowest multiplier possi-
HN_GETSCALE Return the prefix index number (the number of times
number must be divided to fit) instead of formatting
it to the buffer. That is, the scale that would have
been used if HN_AUTOSCALE had been used.
The following flags may be passed in flags:
HN_DECIMAL If the final numeric result is less than 10, and is
not the same as the original value (that is, it has
been scaled) display it using a decimal radix charac-
ter, and one following 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.
Divide number with 1000 instead of 1024. That is,
use decimal scaling instead of binary.
To generate the shortest meaningful value, a buffer length (len) that is
6 greater the length of the suffix along with HN_AUTOSCALE will ensure
the highest meaningful scale is used. Allow one extra byte for the sign
if the number is negative, and one less if the HN_NOSPACE flag is used.
The dehumanize_number() function parses the string representing an inte-
gral 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
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
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.
dehumanize_number() will fail and no number will be stored in result if:
[EINVAL] The string in str was empty or carried an unknown suf-
[ERANGE] The string in str represented a number that does not
fit in result.
strsuftoll(3), orders(7), humanize_number(9)
humanize_number() first appeared in NetBSD 2.0.
dehumanize_number() first appeared in NetBSD 5.0.
NetBSD 9.1 March 11, 2019 NetBSD 9.1