1.\" $NetBSD: getbsize.3,v 1.9 2003/08/07 16:42:48 agc Exp $ 2.\" 3.\" Copyright (c) 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)getbsize.3 8.1 (Berkeley) 6/4/93 31.\" 32.Dd May 30, 2003 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.Nm 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.Nm getbsize 55function returns a pointer to a 56.Dv NUL 57terminated string describing 58the block size, something like 59.Dq 1K-blocks . 60If the 61.Fa headerlenp 62parameter is not 63.Dv NULL 64the memory referenced by 65.Fa headerlenp 66is filled in with the length of the string (not including the 67terminating 68.Dv NUL ) . 69If the 70.Fa blocksizep 71parameter is not 72.Dv NULL 73the memory referenced by 74.Fa blocksizep 75is filled in with block size, in bytes. 76.Pp 77If the user's block size is unreasonable, a warning message is 78written to standard error and the returned information reflects 79a block size of 512 bytes. 80.Sh SEE ALSO 81.Xr df 1 , 82.Xr du 1 , 83.Xr ls 1 , 84.Xr systat 1 , 85.Xr environ 7 86.Sh HISTORY 87The 88.Nm getbsize 89function first appeared in 90.Bx 4.4 . 91