libguile/threads.c

   1 /*      Copyright (C) 1995, 1996, 1997, 1998, 2000, 2002 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.
  12  *
  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.
  26  *
  27  * This exception does not however invalidate any other reasons why
  28  * the executable file might be covered by the GNU General Public License.
  29  *
  30  * This exception applies only to the code released by the
  31  * Free Software Foundation under the name GUILE.  If you copy
  32  * code from other Free Software Foundation releases into a copy of
  33  * GUILE, as the General Public License permits, the exception does
  34  * not apply to the code that you add in this way.  To avoid misleading
  35  * anyone as to the status of such modified files, you must delete
  36  * this exception notice from them.
  37  *
  38  * If you write modifications of your own for GUILE, it is your choice
  39  * whether to permit this exception to apply to your modifications.
  40  * If you do not wish that, delete this exception notice.  */
  41
  42
  43 \f
  44
  45 /* This file does some pretty hairy #inclusion.  It probably seemed
  46    like a good idea at the time, but it doesn't now.  Here's the
  47    structure, edited for relevance (!), last I checked:
  48
  49       threads.c:
  50         threads.h
  51           coop-defs.h
  52             iselect.h
  53         coop-threads.c
  54           coop-threads.h
  55             coop-defs.h*
  56             ../qt/qt.h
  57           coop.c
  58             <qt.h>
  59
  60     * second #inclusion
  61 */
  62
  63 #include <errno.h>
  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_current_thread, "current-thread", 0, 0, 0, scm_current_thread);
 107 SCM_REGISTER_PROC(s_all_thread, "all-threads", 0, 0, 0, scm_all_threads);
 108
 109 SCM_REGISTER_PROC(s_join_thread, "join-thread", 1, 0, 0, scm_join_thread);
 110 /* Suspend execution of the calling thread until the target @var{thread}
 111 terminates, unless the target @var{thread} has already terminated.
 112 */
 113
 114 SCM_DEFINE (scm_thread_exited_p, "thread-exited?", 1, 0, 0,
 115             (SCM thread),
 116             "Return @code{#t} iff @var{thread} has exited.\n")
 117 #define FUNC_NAME s_scm_thread_exited_p
 118 {
 119   return SCM_BOOL (scm_c_thread_exited_p (thread));
 120 }
 121 #undef FUNC_NAME
 122
 123 SCM_REGISTER_PROC(s_make_mutex, "make-mutex", 0, 0, 0, scm_make_mutex);
 124 /* Create a new mutex object. */
 125
 126 SCM_REGISTER_PROC(s_lock_mutex, "lock-mutex", 1, 0, 0, scm_lock_mutex);
 127 /* Lock @var{mutex}. If the mutex is already locked, the calling thread
 128 blocks until the mutex becomes available. The function returns when
 129 the calling thread owns the lock on @var{mutex}. */
 130
 131 SCM_REGISTER_PROC(s_try_mutex, "try-mutex", 1, 0, 0, scm_try_mutex);
 132 /* Try to lock @var{mutex}. If the mutex is already locked by someone
 133 else, return @code{#f}.  Else lock the mutex and return @code{#t}. */
 134
 135 SCM_REGISTER_PROC(s_unlock_mutex, "unlock-mutex", 1, 0, 0, scm_unlock_mutex);
 136 /* Unlocks @var{mutex} if the calling thread owns the lock on @var{mutex}.
 137 Calling unlock-mutex on a mutex not owned by the current thread results
 138 in undefined behaviour. Once a mutex has been unlocked, one thread
 139 blocked on @var{mutex} is awakened and grabs the mutex lock. */
 140
 141 SCM_REGISTER_PROC(s_make_condition_variable, "make-condition-variable", 0, 0, 0, scm_make_condition_variable);
 142
 143 SCM_REGISTER_PROC(s_wait_condition_variable, "wait-condition-variable", 2, 1, 0, scm_timed_wait_condition_variable);
 144
 145 SCM_REGISTER_PROC(s_signal_condition_variable, "signal-condition-variable", 1, 0, 0, scm_signal_condition_variable);
 146
 147 SCM_REGISTER_PROC(s_broadcast_condition_variable, "broadcast-condition-variable", 1, 0, 0, scm_broadcast_condition_variable);
 148
 149 SCM
 150 scm_wait_condition_variable (SCM c, SCM m)
 151 {
 152   return scm_timed_wait_condition_variable (c, m, SCM_UNDEFINED);
 153 }
 154
 155 \f
 156
 157 #ifdef USE_COOP_THREADS
 158 #include "libguile/coop-threads.c"
 159 #else
 160 #ifdef USE_COPT_THREADS
 161 #include "libguile/coop-pthreads.c"
 162 #else
 163 #include "libguile/null-threads.c"
 164 #endif
 165 #endif
 166
 167 \f
 168
 169 #if (SCM_ENABLE_DEPRECATED == 1)
 170
 171 int
 172 scm_mutex_init (scm_t_mutex *m)
 173 {
 174   scm_gc_protect_object (m->m = scm_make_mutex ());
 175   return 0;
 176 }
 177
 178 int
 179 scm_mutex_lock (scm_t_mutex *m)
 180 {
 181   scm_lock_mutex (m->m);
 182   return 0;
 183 }
 184
 185 int
 186 scm_mutex_trylock (scm_t_mutex *m)
 187 {
 188   return SCM_FALSEP (scm_try_mutex (m->m))? EBUSY : 0;
 189 }
 190
 191 int
 192 scm_mutex_unlock (scm_t_mutex *m)
 193 {
 194   scm_unlock_mutex (m->m);
 195   return 0;
 196 }
 197
 198 int
 199 scm_mutex_destroy (scm_t_mutex *m)
 200 {
 201   scm_gc_unprotect_object (m->m);
 202   return 0;
 203 }
 204
 205 SCM_API int
 206 scm_cond_init (scm_t_cond *c, int *cattr)
 207 {
 208   scm_gc_protect_object (c->c = scm_make_condition_variable ());
 209   return 0;
 210 }
 211
 212 int
 213 scm_cond_wait (scm_t_cond *c, scm_t_mutex *m)
 214 {
 215   scm_wait_condition_variable (c->c, m->m);
 216   return 0;
 217 }
 218
 219 int
 220 scm_cond_timedwait (scm_t_cond *c, scm_t_mutex *m,
 221                     const struct timespec *t)
 222 {
 223   return !SCM_FALSEP (scm_timed_wait_condition_variable (
 224     c->c, m->m, scm_cons (scm_long2num (t->tv_sec),
 225                           scm_long2num (t->tv_nsec/1000))));
 226 }
 227
 228 int
 229 scm_cond_signal (scm_t_cond *c)
 230 {
 231   scm_signal_condition_variable (c->c);
 232   return 0;
 233 }
 234
 235 int
 236 scm_cond_broadcast (scm_t_cond *c)
 237 {
 238   scm_broadcast_condition_variable (c->c);
 239   return 0;
 240 }
 241
 242 int
 243 scm_cond_destroy (scm_t_cond *c)
 244 {
 245   scm_gc_unprotect_object (c->c);
 246   return 0;
 247 }
 248
 249 #endif
 250
 251 \f
 252
 253 void
 254 scm_init_threads (SCM_STACKITEM *i)
 255 {
 256   /* Initialize implementation specific details of the threads support */
 257   scm_threads_init (i);
 258 }
 259
 260 void
 261 scm_init_thread_procs ()
 262 {
 263 #include "libguile/threads.x"
 264 }
 265
 266 /*
 267   Local Variables:
 268   c-file-style: "gnu"
 269   End:
 270 */