1.\" $NetBSD: rand.3,v 1.4 1997/07/15 00:42:01 kleink Exp $ 2.\" 3.\" Copyright (c) 1990, 1991 The Regents of the University of California. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" the American National Standards Committee X3, on Information 8.\" Processing Systems. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. All advertising materials mentioning features or use of this software 19.\" must display the following acknowledgement: 20.\" This product includes software developed by the University of 21.\" California, Berkeley and its contributors. 22.\" 4. Neither the name of the University nor the names of its contributors 23.\" may be used to endorse or promote products derived from this software 24.\" without specific prior written permission. 25.\" 26.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36.\" SUCH DAMAGE. 37.\" 38.\" from: @(#)rand.3 6.7 (Berkeley) 6/29/91 39.\" 40.Dd June 29, 1991 41.Dt RAND 3 42.Os 43.Sh NAME 44.Nm rand , 45.Nm srand , 46.Nm rand_r 47.Nd bad random number generator 48.Sh SYNOPSIS 49.Fd #include <stdlib.h> 50.Ft void 51.Fn srand "unsigned int seed" 52.Ft int 53.Fn rand void 54.Ft int 55.Fn rand_r "unsigned int *seed" 56.Sh DESCRIPTION 57.Bf -symbolic 58These interfaces are obsoleted by random(3). 59.Ef 60.Pp 61The 62.Fn rand 63function computes a sequence of pseudo-random integers in the range 64of 0 to 65.Dv RAND_MAX 66(as defined by the header file 67.Aq Pa stdlib.h ) . 68.Pp 69The 70.Fn srand 71function sets its argument as the seed for a new sequence of 72pseudo-random numbers to be returned by 73.Fn rand . 74These sequences are repeatable by calling 75.Fn srand 76with the same seed value. 77.Pp 78If no seed value is provided, the 79.Fn rand 80function is automatically seeded with a value of 1. 81.Pp 82The 83.Fn rand_r 84function is a reentrant interface to 85.Fn rand ; 86the seed has to be supplied and is maintained by the caller. 87.Sh SEE ALSO 88.Xr random 3 89.Sh STANDARDS 90The 91.Fn rand 92and 93.Fn srand 94functions 95conform to 96.St -ansiC . 97The 98.Fn rand_r 99function conforms to 100.St -p1003.1c-95 . 101