1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. All advertising materials mentioning features or use of this software 17.\" must display the following acknowledgement: 18.\" This product includes software developed by the University of 19.\" California, Berkeley and its contributors. 20.\" 4. Neither the name of the University nor the names of its contributors 21.\" may be used to endorse or promote products derived from this software 22.\" without specific prior written permission. 23.\" 24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34.\" SUCH DAMAGE. 35.\" 36.\" @(#)rand.3 8.1 (Berkeley) 6/4/93 37.\" $FreeBSD$ 38.\" 39.Dd May 25, 1999 40.Dt RAND 3 41.Os 42.Sh NAME 43.Nm rand , 44.Nm srand , 45.Nm rand_r 46.Nd bad random number generator 47.Sh SYNOPSIS 48.Fd #include <stdlib.h> 49.Ft void 50.Fn srand "unsigned seed" 51.Ft int 52.Fn rand void 53.Ft int 54.Fn rand_r "unsigned *ctx" 55.Sh DESCRIPTION 56.Bf -symbolic 57These interfaces are obsoleted by random(3). 58.Ef 59.Pp 60The 61.Fn rand 62function computes a sequence of pseudo-random integers in the range 63of 0 to 64.Dv RAND_MAX 65(as defined by the header file 66.Aq Pa stdlib.h ) . 67.Pp 68The 69.Fn srand 70function sets its argument 71.Fa seed 72as the seed for a new sequence of 73pseudo-random numbers to be returned by 74.Fn rand . 75These sequences are repeatable by calling 76.Fn srand 77with the same seed value. 78.Pp 79If no 80.Fa seed 81value is provided, the functions are automatically 82seeded with a value of 1. 83.Pp 84.Fn rand_r 85provides the same functionality as 86.Fn rand . 87A pointer to the context value 88.Fa ctx 89must be supplied 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 . 100.Pp 101The 102.Fn rand_r 103function is as proposed in the POSIX.4a Draft #6 document. 104