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
| 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
|
38.\"
39.Dd May 25, 1999
40.Dt RAND 3
41.Os
42.Sh NAME
43.Nm rand ,
44.Nm srand ,
45.Nm sranddev ,
46.Nm rand_r
47.Nd bad random number generator
48.Sh LIBRARY
49.Lb libc
50.Sh SYNOPSIS
51.Fd #include <stdlib.h>
52.Ft void
53.Fn srand "unsigned seed"
54.Ft void
55.Fn sranddev void
56.Ft int
57.Fn rand void
58.Ft int
59.Fn rand_r "unsigned *ctx"
60.Sh DESCRIPTION
61.Bf -symbolic
| 38.\"
39.Dd May 25, 1999
40.Dt RAND 3
41.Os
42.Sh NAME
43.Nm rand ,
44.Nm srand ,
45.Nm sranddev ,
46.Nm rand_r
47.Nd bad random number generator
48.Sh LIBRARY
49.Lb libc
50.Sh SYNOPSIS
51.Fd #include <stdlib.h>
52.Ft void
53.Fn srand "unsigned seed"
54.Ft void
55.Fn sranddev void
56.Ft int
57.Fn rand void
58.Ft int
59.Fn rand_r "unsigned *ctx"
60.Sh DESCRIPTION
61.Bf -symbolic
|
63.Ef
64.Pp
65The
66.Fn rand
67function computes a sequence of pseudo-random integers in the range
68of 0 to
69.Dv RAND_MAX
70(as defined by the header file
71.Aq Pa stdlib.h ) .
72.Pp
73The
74.Fn srand
75function sets its argument
76.Fa seed
77as the seed for a new sequence of
78pseudo-random numbers to be returned by
79.Fn rand .
80These sequences are repeatable by calling
81.Fn srand
82with the same seed value.
83.Pp
84If no
85.Fa seed
86value is provided, the functions are automatically
87seeded with a value of 1.
88.Pp
89The
90.Fn sranddev
91function initializes a seed using the
92.Xr random 4
93random number device which returns good random numbers,
94suitable for cryptographic use.
95.Pp
96.Fn rand_r
97provides the same functionality as
98.Fn rand .
99A pointer to the context value
100.Fa ctx
101must be supplied by the caller.
102.Sh SEE ALSO
103.Xr random 3 ,
104.Xr random 4
105.Sh STANDARDS
106The
107.Fn rand
108and
109.Fn srand
110functions
111conform to
112.St -isoC .
113.Pp
114The
115.Fn rand_r
116function is as proposed in the POSIX.4a Draft #6 document.
| 64.Ef
65.Pp
66The
67.Fn rand
68function computes a sequence of pseudo-random integers in the range
69of 0 to
70.Dv RAND_MAX
71(as defined by the header file
72.Aq Pa stdlib.h ) .
73.Pp
74The
75.Fn srand
76function sets its argument
77.Fa seed
78as the seed for a new sequence of
79pseudo-random numbers to be returned by
80.Fn rand .
81These sequences are repeatable by calling
82.Fn srand
83with the same seed value.
84.Pp
85If no
86.Fa seed
87value is provided, the functions are automatically
88seeded with a value of 1.
89.Pp
90The
91.Fn sranddev
92function initializes a seed using the
93.Xr random 4
94random number device which returns good random numbers,
95suitable for cryptographic use.
96.Pp
97.Fn rand_r
98provides the same functionality as
99.Fn rand .
100A pointer to the context value
101.Fa ctx
102must be supplied by the caller.
103.Sh SEE ALSO
104.Xr random 3 ,
105.Xr random 4
106.Sh STANDARDS
107The
108.Fn rand
109and
110.Fn srand
111functions
112conform to
113.St -isoC .
114.Pp
115The
116.Fn rand_r
117function is as proposed in the POSIX.4a Draft #6 document.
|