1.\" Copyright (c) 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 4. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)getbsize.3 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD: src/lib/libc/gen/getbsize.3,v 1.11 2007/01/09 00:27:53 imp Exp $ 30.\" $DragonFly: src/lib/libc/gen/getbsize.3,v 1.2 2003/06/17 04:26:42 dillon Exp $ 31.\" 32.Dd June 4, 1993 33.Dt GETBSIZE 3 34.Os 35.Sh NAME 36.Nm getbsize 37.Nd get user block size 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In stdlib.h 42.Ft char * 43.Fn getbsize "int *headerlenp" "long *blocksizep" 44.Sh DESCRIPTION 45The 46.Fn getbsize 47function determines the user's preferred block size based on the value of the 48.Dq BLOCKSIZE 49environment variable; see 50.Xr environ 7 51for details on its use and format. 52.Pp 53The 54.Fn getbsize 55function returns a pointer to a null-terminated string describing 56the block size, something like 57.Dq 1K-blocks . 58The memory referenced by 59.Fa headerlenp 60is filled in with the length of the string (not including the 61terminating null). 62The memory referenced by 63.Fa blocksizep 64is filled in with block size, in bytes. 65.Pp 66If the user's block size is unreasonable, a warning message is 67written to standard error and the returned information reflects 68a block size of 512 bytes. 69.Sh SEE ALSO 70.Xr df 1 , 71.Xr du 1 , 72.Xr ls 1 , 73.Xr systat 1 , 74.Xr environ 7 75.Sh HISTORY 76The 77.Fn getbsize 78function first appeared in 79.Bx 4.4 . 80