June 4, 1993 RAND 3

### NAME

rand, srand, rand_r - bad random number generator

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```void` srand(```unsigned int seed`)
```int` rand(```void`)
```int` rand_r(```unsigned int *seed`)

### DESCRIPTION

These interfaces are obsoleted by random(3).

The rand(``) function computes a sequence of pseudo-random integers in the range of 0 to ```RAND_MAX` (as defined by the header file <```stdlib.h`>).

The srand(``) function sets its argument as the seed for a new sequence of pseudo-random numbers to be returned by rand(``). These sequences are repeatable by calling srand(``) with the same seed value.

If no seed value is provided, the rand(``) function is automatically seeded with a value of 1.

The rand_r(``) function is a reentrant interface to rand(``); the seed has to be supplied and is maintained by the caller.

### SEE ALSO

random(3), rnd(4)

### STANDARDS

The rand(``) and srand(``) functions conform to ANSI X3.159-1989 (``ANSI C89'') . The rand_r(``) function conforms to IEEE Std 1003.1c-1995 (``POSIX.1'') .