1.\"	$OpenBSD: getbsize.3,v 1.10 2013/06/05 03:39:22 tedu Exp $
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30.Dd $Mdocdate: June 5 2013 $
31.Dt GETBSIZE 3
32.Os
33.Sh NAME
34.Nm getbsize
35.Nd get user block size
36.Sh SYNOPSIS
37.In stdlib.h
38.Ft char *
39.Fn getbsize "int *headerlenp" "long *blocksizep"
40.Sh DESCRIPTION
41The
42.Fn getbsize
43function determines the user's preferred block size based on the value of the
44.Ev BLOCKSIZE
45environment variable; see
46.Xr environ 7
47for details on its use and format.
48.Pp
49The
50.Fn getbsize
51function returns a pointer to a NUL-terminated
52string describing
53the block size, something like
54.Qq 1K-blocks .
55The memory referenced by
56.Fa headerlenp
57is filled in with the length of the string (not including the
58terminating NUL byte).
59The memory referenced by
60.Fa blocksizep
61is filled in with the block size, in bytes.
62.Pp
63If the user's block size is unreasonable, a warning message is
64written to standard error and the returned information reflects
65a block size of 512 bytes.
66.Sh SEE ALSO
67.Xr df 1 ,
68.Xr du 1 ,
69.Xr ls 1 ,
70.Xr systat 1 ,
71.Xr environ 7
72.Sh HISTORY
73The
74.Nm getbsize
75function first appeared in
76.Bx 4.4 .
77