workbench/libs/thread/destroycondition.c

   1 /*
   2  * thread.library - threading and synchronisation primitives
   3  *
   4  * Copyright © 2007 Robert Norris
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the same terms as AROS itself.
   8  */
   9
  10 #include "thread_intern.h"
  11
  12 #include <exec/types.h>
  13 #include <proto/exec.h>
  14 #include <assert.h>
  15
  16 /*****************************************************************************
  17
  18     NAME */
  19         AROS_LH1(BOOL, DestroyCondition,
  20
  21 /*  SYNOPSIS */
  22         AROS_LHA(void *, cond, A0),
  23
  24 /*  LOCATION */
  25         struct ThreadBase *, ThreadBase, 16, Thread)
  26
  27 /*  FUNCTION
  28         Destroys a condition variable.
  29
  30     INPUTS
  31         cond - the condition variable to destroy.
  32
  33     RESULT
  34         TRUE if the condition was destroyed, otherwise FALSE.
  35
  36     NOTES
  37         You cannot destroy a condition variable if other threads are waiting on
  38         it.
  39
  40     EXAMPLE
  41         DestroyCondition(cond);
  42
  43     BUGS
  44
  45     SEE ALSO
  46         CreateCondition(), WaitCondition(), SignalCondition(),
  47         BroadcastCondition()
  48
  49     INTERNALS
  50
  51 *****************************************************************************/
  52 {
  53     AROS_LIBFUNC_INIT
  54
  55     struct _Condition *c = (struct _Condition *) cond;
  56
  57     assert(c != NULL);
  58
  59     /* we can only destroy the cond if noone is waiting on it */
  60     ObtainSemaphoreShared(&c->lock);
  61     if (c->count > 0) {
  62         ReleaseSemaphore(&c->lock);
  63         return FALSE;
  64     }
  65
  66     FreeMem(c, sizeof(struct _Condition));
  67
  68     return TRUE;
  69
  70     AROS_LIBFUNC_EXIT
  71 } /* DestroyCondition */