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.\" 38.Dd May 25, 1999 39.Dt RAND 3 40.Os 41.Sh NAME 42.Nm rand , 43.Nm srand , 44.Nm rand_r 45.Nd bad random number generator 46.Sh SYNOPSIS 47.Fd #include <stdlib.h> 48.Ft void 49.Fn srand "unsigned seed" 50.Ft int 51.Fn rand void 52.Ft int 53.Fn rand_r "unsigned *ctx" 54.Sh DESCRIPTION 55.Bf -symbolic 56These interfaces are obsoleted by random(3). 57.Ef 58.Pp 59The 60.Fn rand 61function computes a sequence of pseudo-random integers in the range 62of 0 to 63.Dv RAND_MAX 64(as defined by the header file 65.Aq Pa stdlib.h ) . 66.Pp 67The 68.Fn srand 69function sets its argument 70.Fa seed 71as 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 79.Fa seed 80value is provided, the functions are automatically 81seeded with a value of 1. 82.Pp 83.Fn rand_r 84provides the same functionality as 85.Fn rand . 86A pointer to the context value 87.Fa ctx 88must be supplied by the caller. 89.Sh SEE ALSO 90.Xr random 3 91.Sh STANDARDS 92The 93.Fn rand 94and 95.Fn srand 96functions 97conform to 98.St -ansiC . 99.Pp 100The 101.Fn rand_r 102function is as proposed in the POSIX.4a Draft #6 document. 103