NetBSD/lib/libc/stdlib/rand.3

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.\"     from: @(#)rand.3	8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt RAND 3
.Os
.Sh NAME
.Nm rand ,
.Nm srand ,
.Nm rand_r
.Nd bad random number generator
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.Fd #include \*[Lt]stdlib.h\*[Gt]
.Ft void
.Fn srand "unsigned int seed"
.Ft int
.Fn rand void
.Ft int
.Fn rand_r "unsigned int *seed"
.Sh DESCRIPTION
.Bf -symbolic
These interfaces are obsoleted by
.Xr random 3 .
.Ef
.Pp
The
.Fn rand
function computes a sequence of pseudo-random integers in the range
of 0 to
.Dv RAND_MAX
(as defined by the header file
.Aq Pa stdlib.h ) .
.Pp
The
.Fn srand
function sets its argument as the seed for a new sequence of
pseudo-random numbers to be returned by
.Fn rand .
These sequences are repeatable by calling
.Fn srand
with the same seed value.
.Pp
If no seed value is provided, the
.Fn rand
function is automatically seeded with a value of 1.
.Pp
The
.Fn rand_r
function is a reentrant interface to
.Fn rand ;
the seed has to be supplied and is maintained by the caller.
.Sh SEE ALSO
.Xr random 3
.Sh STANDARDS
The
.Fn rand
and
.Fn srand
functions
conform to
.St -ansiC .
The
.Fn rand_r
function conforms to
.St -p1003.1c-95 .