arch/.unmaintained/m68k-emul/forbid.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <exec/execbase.h>
   7
   8 /******************************************************************************
   9
  10     NAME
  11 #include <proto/exec.h>
  12
  13         AROS_LH0(void, Forbid,
  14
  15     LOCATION
  16         struct ExecBase *, SysBase, 22, Exec)
  17
  18     FUNCTION
  19         Forbid any further taskswitches until a matching call to Permit().
  20         Naturally disabling taskswitches means:
  21
  22         THIS CALL IS DANGEROUS
  23
  24         Do not use it without thinking very well about it or better do not
  25         use it at all. Most of the time you can live without it by using
  26         semaphores or similar.
  27
  28         Calls to Forbid() nest, i.e. for each call to Forbid() you need one
  29         call to Enable().
  30
  31     INPUTS
  32         None.
  33
  34     RESULT
  35         None.
  36
  37     NOTES
  38         To prevent deadlocks calling Wait() in forbidden state breaks the
  39         forbid - thus taskswitches may happen again.
  40
  41     EXAMPLE
  42
  43     BUGS
  44
  45     SEE ALSO
  46         Permit(), Disable(), Enable(), Wait()
  47
  48     INTERNALS
  49
  50     HISTORY
  51
  52 ******************************************************************************/
  53
  54 /* The real function is written in assembler as stub which calls me */
  55 void _Forbid (struct ExecBase * SysBase)
  56 {
  57     ++SysBase->TDNestCnt;
  58 } /* _Forbid */