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 LIBRARY 48.Lb libc 49.Sh SYNOPSIS 50.Fd #include <stdlib.h> 51.Ft void 52.Fn srand "unsigned seed" 53.Ft int 54.Fn rand void 55.Ft int 56.Fn rand_r "unsigned *ctx" 57.Sh DESCRIPTION 58.Bf -symbolic 59These interfaces are obsoleted by random(3). 60.Ef 61.Pp 62The 63.Fn rand 64function computes a sequence of pseudo-random integers in the range 65of 0 to 66.Dv RAND_MAX 67(as defined by the header file 68.Aq Pa stdlib.h ) . 69.Pp 70The 71.Fn srand 72function sets its argument 73.Fa seed 74as 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 82.Fa seed 83value is provided, the functions are automatically 84seeded with a value of 1. 85.Pp 86.Fn rand_r 87provides the same functionality as 88.Fn rand . 89A pointer to the context value 90.Fa ctx 91must be supplied by the caller. 92.Sh SEE ALSO 93.Xr random 3 94.Sh STANDARDS 95The 96.Fn rand 97and 98.Fn srand 99functions 100conform to 101.St -ansiC . 102.Pp 103The 104.Fn rand_r 105function is as proposed in the POSIX.4a Draft #6 document. 106