libguile/threads.c

   1 /*      Copyright (C) 1995, 1996, 1997, 1998, 2000 Free Software Foundation, Inc.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2, or (at your option)
   6  * any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
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  13  * You should have received a copy of the GNU General Public License
  14  * along with this software; see the file COPYING.  If not, write to
  15  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16  * Boston, MA 02111-1307 USA
  17  *
  18  * As a special exception, the Free Software Foundation gives permission
  19  * for additional uses of the text contained in its release of GUILE.
  20  *
  21  * The exception is that, if you link the GUILE library with other files
  22  * to produce an executable, this does not by itself cause the
  23  * resulting executable to be covered by the GNU General Public License.
  24  * Your use of that executable is in no way restricted on account of
  25  * linking the GUILE library code into it.
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  29  *
  30  * This exception applies only to the code released by the
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  41
  42 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  43    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  44
  45 \f
  46
  47 /* This file does some pretty hairy #inclusion.  It probably seemed
  48    like a good idea at the time, but it doesn't now.  Here's the
  49    structure, edited for relevance (!), last I checked:
  50
  51       threads.c:
  52         threads.h
  53           coop-defs.h
  54             iselect.h
  55         coop-threads.c
  56           coop-threads.h
  57             coop-defs.h*
  58             ../qt/qt.h
  59           coop.c
  60             <qt.h>
  61
  62     * second #inclusion
  63 */
  64
  65 #include "libguile/_scm.h"
  66 #include "libguile/dynwind.h"
  67 #include "libguile/smob.h"
  68
  69 #include "libguile/threads.h"
  70
  71 \f
  72
  73 scm_t_bits scm_tc16_thread;
  74 scm_t_bits scm_tc16_mutex;
  75 scm_t_bits scm_tc16_condvar;
  76
  77 \f
  78 /* Scheme-visible thread functions. */
  79
  80 #ifdef USE_COOP_THREADS
  81 SCM_REGISTER_PROC(s_single_thread_p, "single-active-thread?", 0, 0, 0, scm_single_thread_p);
  82 #endif
  83
  84 /* GJB:FIXME:DOC: SCM_REGISTER_PROC needs to permit a docstring,
  85    or these need to move into the file where the proc is defined. */
  86
  87 SCM_REGISTER_PROC(s_yield, "yield", 0, 0, 0, scm_yield);
  88 /* If one or more threads are waiting to execute, calling yield forces an
  89 immediate context switch to one of them. Otherwise, yield has no effect.
  90 */
  91
  92 SCM_REGISTER_PROC(s_call_with_new_thread, "call-with-new-thread", 0, 0, 1, scm_call_with_new_thread);
  93 /* Evaluate @var{(thunk)} in a new thread, and new dynamic context,
  94 returning a new thread object representing the thread.
  95
  96 If an error occurs during evaluation, call error-thunk, passing it an
  97 error code describing the condition.  [Error codes are currently
  98 meaningless integers.  In the future, real values will be specified.]
  99 If this happens, the error-thunk is called outside the scope of the new
 100 root -- it is called in the same dynamic context in which
 101 with-new-thread was evaluated, but not in the callers thread.
 102
 103 All the evaluation rules for dynamic roots apply to threads.
 104 */
 105
 106 SCM_REGISTER_PROC(s_join_thread, "join-thread", 1, 0, 0, scm_join_thread);
 107 /* Suspend execution of the calling thread until the target @var{thread}
 108 terminates, unless the target @var{thread} has already terminated.
 109 */
 110
 111 SCM_REGISTER_PROC(s_make_mutex, "make-mutex", 0, 0, 0, scm_make_mutex);
 112 /* Create a new mutex object. */
 113
 114 SCM_REGISTER_PROC(s_lock_mutex, "lock-mutex", 1, 0, 0, scm_lock_mutex);
 115 /* Lock @var{mutex}. If the mutex is already locked, the calling thread
 116 blocks until the mutex becomes available. The function returns when
 117 the calling thread owns the lock on @var{mutex}. */
 118
 119 SCM_REGISTER_PROC(s_unlock_mutex, "unlock-mutex", 1, 0, 0, scm_unlock_mutex);
 120 /* Unlocks @var{mutex} if the calling thread owns the lock on @var{mutex}.
 121 Calling unlock-mutex on a mutex not owned by the current thread results
 122 in undefined behaviour. Once a mutex has been unlocked, one thread
 123 blocked on @var{mutex} is awakened and grabs the mutex lock. */
 124
 125 SCM_REGISTER_PROC(s_make_condition_variable, "make-condition-variable", 0, 0, 0, scm_make_condition_variable);
 126
 127 SCM_REGISTER_PROC(s_wait_condition_variable, "wait-condition-variable", 2, 0, 0, scm_wait_condition_variable);
 128
 129 SCM_REGISTER_PROC(s_signal_condition_variable, "signal-condition-variable", 1, 0, 0, scm_signal_condition_variable);
 130
 131 \f
 132
 133 #ifdef USE_COOP_THREADS
 134 #include "libguile/coop-threads.c"
 135 #endif
 136
 137 \f
 138
 139 void
 140 scm_init_threads (SCM_STACKITEM *i)
 141 {
 142   scm_tc16_thread = scm_make_smob_type ("thread", 0);
 143   scm_tc16_mutex = scm_make_smob_type ("mutex", sizeof (coop_m));
 144   scm_tc16_condvar = scm_make_smob_type ("condition-variable", sizeof (coop_c));
 145
 146 #ifndef SCM_MAGIC_SNARFER
 147 #include "libguile/threads.x"
 148 #endif
 149   /* Initialize implementation specific details of the threads support */
 150   scm_threads_init (i);
 151 }
 152
 153 /*
 154   Local Variables:
 155   c-file-style: "gnu"
 156   End:
 157 */