1.\" $OpenBSD: getbsize.3,v 1.10 2013/06/05 03:39:22 tedu 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.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