1.\" $NetBSD: rand.3,v 1.8 2002/02/07 07:00:30 ross Exp $ 2.\" 3.\" Copyright (c) 1990, 1991, 1993 4.\" The Regents of the University of California. 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 8.1 (Berkeley) 6/4/93 39.\" 40.Dd June 4, 1993 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 LIBRARY 49.Lb libc 50.Sh SYNOPSIS 51.Fd #include \*[Lt]stdlib.h\*[Gt] 52.Ft void 53.Fn srand "unsigned int seed" 54.Ft int 55.Fn rand void 56.Ft int 57.Fn rand_r "unsigned int *seed" 58.Sh DESCRIPTION 59.Bf -symbolic 60These interfaces are obsoleted by 61.Xr random 3 . 62.Ef 63.Pp 64The 65.Fn rand 66function computes a sequence of pseudo-random integers in the range 67of 0 to 68.Dv RAND_MAX 69(as defined by the header file 70.Aq Pa stdlib.h ) . 71.Pp 72The 73.Fn srand 74function sets its argument as the seed for a new sequence of 75pseudo-random numbers to be returned by 76.Fn rand . 77These sequences are repeatable by calling 78.Fn srand 79with the same seed value. 80.Pp 81If no seed value is provided, the 82.Fn rand 83function is automatically seeded with a value of 1. 84.Pp 85The 86.Fn rand_r 87function is a reentrant interface to 88.Fn rand ; 89the seed has to be supplied and is maintained by the caller. 90.Sh SEE ALSO 91.Xr random 3 92.Sh STANDARDS 93The 94.Fn rand 95and 96.Fn srand 97functions 98conform to 99.St -ansiC . 100The 101.Fn rand_r 102function conforms to 103.St -p1003.1c-95 . 104