freebsd man page for getbsize

GETBSIZE(3)						   BSD Library Functions Manual 					       GETBSIZE(3)

NAME
     getbsize -- get preferred block size

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <stdlib.h>

     char *
     getbsize(int *headerlenp, long *blocksizep);

DESCRIPTION
     The getbsize() function returns a preferred block size for reporting by system utilities df(1), du(1), ls(1) and systat(1), based on the
     value of the BLOCKSIZE environment variable.  BLOCKSIZE may be specified directly in bytes, or in multiples of a kilobyte by specifying a
     number followed by ``K'' or ``k'', in multiples of a megabyte by specifying a number followed by ``M'' or ``m'' or in multiples of a gigabyte
     by specifying a number followed by ``G'' or ``g''.  Multiples must be integers.

     Valid values of BLOCKSIZE are 512 bytes to 1 gigabyte.  Sizes less than 512 bytes are rounded up to 512 bytes, and sizes greater than 1 GB
     are rounded down to 1 GB.	In each case getbsize() produces a warning message.

     The getbsize() function returns a pointer to a null-terminated string describing the block size, something like ``1K-blocks''.  The memory
     referenced by headerlenp is filled in with the length of the string (not including the terminating null).	The memory referenced by
     blocksizep is filled in with block size, in bytes.

SEE ALSO
     df(1), du(1), ls(1), systat(1), environ(7)

HISTORY
     The getbsize() function first appeared in 4.4BSD.

BSD
								 November 16, 2012							       BSD