1.\" $NetBSD: getbsize.3,v 1.8 2003/05/30 02:22:23 simonb 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. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)getbsize.3 8.1 (Berkeley) 6/4/93 35.\" 36.Dd May 30, 2003 37.Dt GETBSIZE 3 38.Os 39.Sh NAME 40.Nm getbsize 41.Nd get user block size 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In stdlib.h 46.Ft char * 47.Fn getbsize "int *headerlenp" "long *blocksizep" 48.Sh DESCRIPTION 49The 50.Nm getbsize 51function determines the user's preferred block size based on the value of the 52.Dq BLOCKSIZE 53environment variable; see 54.Xr environ 7 55for details on its use and format. 56.Pp 57The 58.Nm getbsize 59function returns a pointer to a 60.Dv NUL 61terminated string describing 62the block size, something like 63.Dq 1K-blocks . 64If the 65.Fa headerlenp 66parameter is not 67.Dv NULL 68the memory referenced by 69.Fa headerlenp 70is filled in with the length of the string (not including the 71terminating 72.Dv NUL ) . 73If the 74.Fa blocksizep 75parameter is not 76.Dv NULL 77the memory referenced by 78.Fa blocksizep 79is filled in with block size, in bytes. 80.Pp 81If the user's block size is unreasonable, a warning message is 82written to standard error and the returned information reflects 83a block size of 512 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 91The 92.Nm getbsize 93function first appeared in 94.Bx 4.4 . 95