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1 | .\" Copyright (c) 1990, 1991 The Regents of the University of California. | ||
2 | .\" 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. Neither the name of the University nor the names of its contributors | ||
17 | .\" may be used to endorse or promote products derived from this software | ||
18 | .\" without specific prior written permission. | ||
19 | .\" | ||
20 | .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | ||
21 | .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | ||
22 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | ||
23 | .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | ||
24 | .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | ||
25 | .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | ||
26 | .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | ||
27 | .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | ||
28 | .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | ||
29 | .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | ||
30 | .\" SUCH DAMAGE. | ||
31 | .\" | ||
32 | .\" $OpenBSD: rand.3,v 1.9 2003/06/02 20:18:38 millert Exp $ | ||
33 | .\" | ||
34 | .Dd June 29, 1991 | ||
35 | .Dt RAND 3 | ||
36 | .Os | ||
37 | .Sh NAME | ||
38 | .Nm rand , | ||
39 | .Nm srand | ||
40 | .Nd bad random number generator | ||
41 | .Sh SYNOPSIS | ||
42 | .Fd #include <stdlib.h> | ||
43 | .Ft void | ||
44 | .Fn srand "unsigned int seed" | ||
45 | .Ft int | ||
46 | .Fn rand void | ||
47 | .Ft int | ||
48 | .Fn rand_r "unsigned int *seed" | ||
49 | .Sh DESCRIPTION | ||
50 | .Bf -symbolic | ||
51 | These interfaces are obsoleted by | ||
52 | .Xr random 3 . | ||
53 | .Ef | ||
54 | .Pp | ||
55 | The | ||
56 | .Fn rand | ||
57 | function computes a sequence of pseudo-random integers in the range | ||
58 | of 0 to | ||
59 | .Dv RAND_MAX | ||
60 | (as defined by the header file | ||
61 | .Aq Pa stdlib.h ) . | ||
62 | .Pp | ||
63 | The | ||
64 | .Fn srand | ||
65 | function sets its argument as the seed for a new sequence of | ||
66 | pseudo-random numbers to be returned by | ||
67 | .Fn rand . | ||
68 | These sequences are repeatable by calling | ||
69 | .Fn srand | ||
70 | with the same seed value. | ||
71 | .Pp | ||
72 | If no seed value is provided, the functions are automatically | ||
73 | seeded with a value of 1. | ||
74 | .Pp | ||
75 | The | ||
76 | .Fn rand_r | ||
77 | is a thread-safe version of | ||
78 | .Fn rand . | ||
79 | Storage for the seed must be provided through the | ||
80 | .Fa seed | ||
81 | argument, and needs to have been initialized by the caller. | ||
82 | .Sh SEE ALSO | ||
83 | .Xr arc4random 3 , | ||
84 | .Xr rand48 3 , | ||
85 | .Xr random 3 | ||
86 | .Sh STANDARDS | ||
87 | The | ||
88 | .Fn rand | ||
89 | and | ||
90 | .Fn srand | ||
91 | functions conform to | ||
92 | .St -ansiC . | ||
93 | .Pp | ||
94 | The | ||
95 | .Fn rand_r | ||
96 | function conforms to ISO/IEC 9945-1 ANSI/IEEE | ||
97 | .Pq Dq Tn POSIX | ||
98 | Std 1003.1c Draft 10. | ||