libguile/threads.c

   1 /*      Copyright (C) 1995, 1996, 1997, 1998 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
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  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 /* 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         mit-pthreads.c
  56         coop-threads.c
  57           coop-threads.h
  58             coop-defs.h*
  59             ../qt/qt.h
  60           coop.c
  61             <qt.h>
  62
  63     * second #inclusion
  64 */
  65
  66 #include <stdio.h>
  67 #include "_scm.h"
  68 #include "dynwind.h"
  69 #include "smob.h"
  70
  71 #include "threads.h"
  72
  73 \f
  74
  75 long scm_tc16_thread;
  76
  77 long scm_tc16_mutex;
  78
  79 long scm_tc16_condvar;
  80
  81 \f
  82 /* Scheme-visible thread functions. */
  83
  84 #ifdef USE_COOP_THREADS
  85 SCM_REGISTER_PROC(s_single_thread_p, "single-active-thread?", 0, 0, 0, scm_single_thread_p);
  86 #endif
  87
  88 /* GJB:FIXME:DOC: SCM_REGISTER_PROC needs to permit a docstring,
  89    or these need to move into the file where the proc is defined. */
  90
  91 SCM_REGISTER_PROC(s_yield, "yield", 0, 0, 0, scm_yield);
  92 /* If one or more threads are waiting to execute, calling yield forces an
  93 immediate context switch to one of them. Otherwise, yield has no effect.
  94 */
  95
  96 SCM_REGISTER_PROC(s_call_with_new_thread, "call-with-new-thread", 0, 0, 1, scm_call_with_new_thread);
  97 /* Evaluate @var{(thunk)} in a new thread, and new dynamic context,
  98 returning a new thread object representing the thread.
  99
 100 If an error occurs during evaluation, call error-thunk, passing it an
 101 error code describing the condition.  [Error codes are currently
 102 meaningless integers.  In the future, real values will be specified.]
 103 If this happens, the error-thunk is called outside the scope of the new
 104 root -- it is called in the same dynamic context in which
 105 with-new-thread was evaluated, but not in the callers thread.
 106
 107 All the evaluation rules for dynamic roots apply to threads.
 108 */
 109
 110 SCM_REGISTER_PROC(s_join_thread, "join-thread", 1, 0, 0, scm_join_thread);
 111 /* Suspend execution of the calling thread until the target @var{thread}
 112 terminates, unless the target @var{thread} has already terminated.
 113 */
 114
 115 SCM_REGISTER_PROC(s_make_mutex, "make-mutex", 0, 0, 0, scm_make_mutex);
 116 /* Create a new mutex object. */
 117
 118 SCM_REGISTER_PROC(s_lock_mutex, "lock-mutex", 1, 0, 0, scm_lock_mutex);
 119 /* Lock @var{mutex}. If the mutex is already locked, the calling thread
 120 blocks until the mutex becomes available. The function returns when
 121 the calling thread owns the lock on @var{mutex}. */
 122
 123 SCM_REGISTER_PROC(s_unlock_mutex, "unlock-mutex", 1, 0, 0, scm_unlock_mutex);
 124 /* Unlocks @var{mutex} if the calling thread owns the lock on @var{mutex}.
 125 Calling unlock-mutex on a mutex not owned by the current thread results
 126 in undefined behaviour. Once a mutex has been unlocked, one thread
 127 blocked on @var{mutex} is awakened and grabs the mutex lock. */
 128
 129 SCM_REGISTER_PROC(s_make_condition_variable, "make-condition-variable", 0, 0, 0, scm_make_condition_variable);
 130
 131 SCM_REGISTER_PROC(s_wait_condition_variable, "wait-condition-variable", 2, 0, 0, scm_wait_condition_variable);
 132
 133 SCM_REGISTER_PROC(s_signal_condition_variable, "signal-condition-variable", 1, 0, 0, scm_signal_condition_variable);
 134
 135 \f
 136
 137 #ifdef USE_MIT_PTHREADS
 138 #include "mit-pthreads.c"
 139 #endif
 140
 141 #ifdef USE_COOP_THREADS
 142 #include "coop-threads.c"
 143 #endif
 144
 145 \f
 146
 147 void
 148 scm_init_threads (SCM_STACKITEM *i)
 149 {
 150   scm_tc16_thread = scm_make_smob_type ("thread", sizeof (coop_t));
 151   scm_tc16_mutex = scm_make_smob_type ("mutex", sizeof (coop_m));
 152   scm_tc16_condvar = scm_make_smob_type ("condition-variable", sizeof (coop_c));
 153
 154 #include "threads.x"
 155   /* Initialize implementation specific details of the threads support */
 156   scm_threads_init (i);
 157 }
 158
 159 /*
 160   Local Variables:
 161   c-file-style: "gnu"
 162   End:
 163 */