humanize_number(9) [netbsd man page]

HUMANIZE_NUMBER(9)					   BSD Kernel Developer's Manual					HUMANIZE_NUMBER(9)

NAME

     humanize_number, format_bytes -- human readable numbers

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

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

     If the formatted number (including suffix) is too long to fit into buf, humanize_number() divides number by divisor until it will fit.  In
     this case, suffix is prefixed 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

     The len argument must be at least 4 plus the length of suffix, in order to ensure a useful result in buf.

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

RETURN VALUES

     Both functions return the number of characters stored in buf (excluding the terminating NUL) upon success, or -1 upon failure.

SEE ALSO

     humanize_number(3)

HISTORY

     These functions first appeared in NetBSD 1.5.

BSD
								  August 7, 2010							       BSD

HUMANIZE_NUMBER(3)					   BSD Library Functions Manual 					HUMANIZE_NUMBER(3)

NAME

     humanize_number -- format a number into a human readable form

LIBRARY

     System Utilities Library (libutil, -lutil)

SYNOPSIS

     #include <libutil.h>

     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 buf.  A space and then suffix is appended to the end.
     The buffer pointed to by buf must be at least len bytes long.

     If the formatted number (including suffix) would be too long to fit into buf, then divide number by 1024 until it will.  In this case, prefix
     suffix with the appropriate designator.  The humanize_number() function follows the traditional computer science conventions by default,
     rather than the IEE/IEC (and now also SI) power of two convention or the power of ten notion.  This behaviour however can be altered by spec-
     ifying the HN_DIVISOR_1000 and HN_IEC_PREFIXES flags.

     The traditional (default) prefixes are:

	   Prefix    Description    Multiplier		   Multiplier 1000x
	   (note)    kilo	    1024		   1000
	   M	     mega	    1048576		   1000000
	   G	     giga	    1073741824		   1000000000
	   T	     tera	    1099511627776	   1000000000000
	   P	     peta	    1125899906842624	   1000000000000000
	   E	     exa	    1152921504606846976    1000000000000000000

     Note: An uppercase K indicates a power of two, a lowercase k a power of ten.

     The IEE/IEC (and now also SI) power of two prefixes are:

	   Prefix    Description    Multiplier
	   Ki	     kibi	    1024
	   Mi	     mebi	    1048576
	   Gi	     gibi	    1073741824
	   Ti	     tebi	    1099511627776
	   Pi	     pebi	    1125899906842624
	   Ei	     exbi	    1152921504606846976

     The len argument must be at least 4 plus the length of suffix, in order to ensure a useful result is generated into buf.  To use a specific
     prefix, specify this as scale (multiplier = 1024 ^ scale; when HN_DIVISOR_1000 is specified, multiplier = 1000 ^ scale).  This cannot be com-
     bined 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 decimal place.

	   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.

	   HN_IEC_PREFIXES  Use the IEE/IEC notion of prefixes (Ki, Mi, Gi...).  This flag has no effect when HN_DIVISOR_1000 is also specified.

RETURN VALUES

     Upon success, the humanize_number function returns the number of characters that would have been stored in buf (excluding the terminating
     NUL) if buf was large enough, or -1 upon failure.	Even upon failure, the contents of buf may be modified.  If HN_GETSCALE is specified, the
     prefix index number will be returned instead.

SEE ALSO

     expand_number(3)

STANDARDS

     The HN_DIVISOR_1000 and HN_IEC_PREFIXES flags conform to ISO/IEC Std 80000-13:2008 and IEEE Std 1541-2002.

HISTORY

     The humanize_number() function first appeared in NetBSD 2.0 and then in FreeBSD 5.3.  The HN_IEC_PREFIXES flag was introduced in FreeBSD 9.0.

BSD
								  October 7, 2013							       BSD