compiler/clib/rand.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     ANSI C functions rand() and srand().
   6 */
   7
   8 static unsigned int a = 1;
   9
  10 /*****************************************************************************
  11
  12     NAME */
  13 #include <stdlib.h>
  14
  15         int rand (
  16
  17 /*  SYNOPSIS */
  18         void)
  19
  20 /*  FUNCTION
  21         A random number generator.
  22
  23     INPUTS
  24         None.
  25
  26     RESULT
  27         A pseudo-random integer between 0 and RAND_MAX.
  28
  29     NOTES
  30         This function must not be used in a shared library or
  31         in a threaded application.
  32
  33     EXAMPLE
  34
  35     BUGS
  36
  37     SEE ALSO
  38
  39     INTERNALS
  40
  41 ******************************************************************************/
  42 {
  43     return (a = a * 1103515245 + 12345) % RAND_MAX;
  44 } /* rand */
  45
  46
  47 #define srand srand
  48 /*****************************************************************************
  49
  50     NAME */
  51         #include <stdlib.h>
  52
  53         void srand (
  54
  55 /*  SYNOPSIS */
  56         unsigned int seed)
  57
  58 /*  FUNCTION
  59         Set the starting value for the random number generator rand()
  60
  61     INPUTS
  62         seed - New start value
  63
  64     RESULT
  65         None.
  66
  67     NOTES
  68         This function must not be used in a shared library or
  69         in a threaded application.
  70
  71     EXAMPLE
  72
  73     BUGS
  74
  75     SEE ALSO
  76
  77     INTERNALS
  78
  79 ******************************************************************************/
  80 {
  81     a = seed;
  82 } /* srand */
  83
  84