workbench/libs/thread/trylockmutex.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/semaphores.h>
  13 #include <proto/exec.h>
  14 #include <assert.h>
  15
  16 /*****************************************************************************
  17
  18     NAME */
  19         AROS_LH1(BOOL, TryLockMutex,
  20
  21 /*  SYNOPSIS */
  22         AROS_LHA(void *, mutex, A0),
  23
  24 /*  LOCATION */
  25         struct ThreadBase *, ThreadBase, 13, Thread)
  26
  27 /*  FUNCTION
  28         Tries to lock a mutex. If the lock is already held, this function
  29         fails.
  30
  31     INPUTS
  32         mutex - mutex to lock.
  33
  34     RESULT
  35         TRUE if the lock was acquired, FALSE if the lock is already held.
  36
  37     NOTES
  38
  39     EXAMPLE
  40         TryLockMutex(mutex);
  41
  42     BUGS
  43
  44     SEE ALSO
  45         CreateMutex(), DestroyMutex(), LockMutex(), UnlockMutex()
  46
  47     INTERNALS
  48         Mutexes are implemented as thin wrappers around Exec semaphores.
  49 *****************************************************************************/
  50 {
  51     AROS_LIBFUNC_INIT
  52
  53     assert(mutex != NULL);
  54
  55     return (BOOL) AttemptSemaphore((struct SignalSemaphore *) mutex);
  56
  57     AROS_LIBFUNC_EXIT
  58 } /* TryLockMutex */