humanize_number(3) - NetBSD Manual Pages

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HUMANIZE_NUMBER(3)      NetBSD Library Functions Manual     HUMANIZE_NUMBER(3)


NAME

     dehumanize_number, humanize_number -- format a number into a human read-
     able 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, spec-
     ify 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 possi-
                         ble.

           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 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
     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 suf-
                        fix.

     [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.

NetBSD 8.0                     January 14, 2011                     NetBSD 8.0