gen/FreeBSD/getbsize.3

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  28 .\"     @(#)getbsize.3  8.1 (Berkeley) 6/4/93
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  31 .Dd November 16, 2012
  32 .Dt GETBSIZE 3
  33 .Os
  34 .Sh NAME
  35 .Nm getbsize
  36 .Nd get preferred block size
  37 .Sh LIBRARY
  38 .Lb libc
  39 .Sh SYNOPSIS
  40 .In stdlib.h
  41 .Ft char *
  42 .Fn getbsize "int *headerlenp" "long *blocksizep"
  43 .Sh DESCRIPTION
  44 The
  45 .Fn getbsize
  46 function returns a preferred block size for reporting by system utilities
  47 .Xr df 1 ,
  48 .Xr du 1 ,
  49 .Xr ls 1
  50 and
  51 .Xr systat 1 ,
  52 based on the value of the
  53 .Ev BLOCKSIZE
  54 environment variable.
  55 .Ev BLOCKSIZE
  56 may be specified directly in bytes, or in multiples of a kilobyte by
  57 specifying a number followed by ``K'' or ``k'', in multiples of a
  58 megabyte by specifying a number followed by ``M'' or ``m'' or in
  59 multiples of a gigabyte by specifying a number followed by ``G'' or
  60 ``g''.
  61 Multiples must be integers.
  62 .Pp
  63 Valid values of
  64 .Ev BLOCKSIZE
  65 are 512 bytes to 1 gigabyte.
  66 Sizes less than 512 bytes are rounded up to 512 bytes, and sizes
  67 greater than 1 GB are rounded down to 1 GB.
  68 In each case
  69 .Fn getbsize
  70 produces a warning message.
  71 .Pp
  72 The
  73 .Fn getbsize
  74 function returns a pointer to a null-terminated string describing
  75 the block size, something like
  76 .Dq 1K-blocks .
  77 The memory referenced by
  78 .Fa headerlenp
  79 is filled in with the length of the string (not including the
  80 terminating null).
  81 The memory referenced by
  82 .Fa blocksizep
  83 is filled in with block size, in bytes.
  84 .Sh SEE ALSO
  85 .Xr df 1 ,
  86 .Xr du 1 ,
  87 .Xr ls 1 ,
  88 .Xr systat 1 ,
  89 .Xr environ 7
  90 .Sh HISTORY
  91 The
  92 .Fn getbsize
  93 function first appeared in
  94 .Bx 4.4 .