xref: /netbsd-src/lib/libc/stdlib/rand.3 (revision 2a399c6883d870daece976daec6ffa7bb7f934ce)
1.\"	$NetBSD: rand.3,v 1.4 1997/07/15 00:42:01 kleink Exp $
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38.\"     from: @(#)rand.3	6.7 (Berkeley) 6/29/91
39.\"
40.Dd June 29, 1991
41.Dt RAND 3
42.Os
43.Sh NAME
44.Nm rand ,
45.Nm srand ,
46.Nm rand_r
47.Nd bad random number generator
48.Sh SYNOPSIS
49.Fd #include <stdlib.h>
50.Ft void
51.Fn srand "unsigned int seed"
52.Ft int
53.Fn rand void
54.Ft int
55.Fn rand_r "unsigned int *seed"
56.Sh DESCRIPTION
57.Bf -symbolic
58These interfaces are obsoleted by random(3).
59.Ef
60.Pp
61The
62.Fn rand
63function computes a sequence of pseudo-random integers in the range
64of 0 to
65.Dv RAND_MAX
66(as defined by the header file
67.Aq Pa stdlib.h ) .
68.Pp
69The
70.Fn srand
71function sets its argument as 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 seed value is provided, the
79.Fn rand
80function is automatically seeded with a value of 1.
81.Pp
82The
83.Fn rand_r
84function is a reentrant interface to
85.Fn rand ;
86the seed has to be supplied and is maintained by the caller.
87.Sh SEE ALSO
88.Xr random 3
89.Sh STANDARDS
90The
91.Fn rand
92and
93.Fn srand
94functions
95conform to
96.St -ansiC .
97The
98.Fn rand_r
99function conforms to
100.St -p1003.1c-95 .
101