* coop-threads.c: Don't join finished threads. Thanks to Julian Satchell.

* coop.c: Removed old non-working code.

THANKS

@@ -1,14 +1,14 @@
 The Guile maintainer committee consists of
 
 	Jim Blandy
+     Mikael Djurfeldt
      Maciej Stachowiak
      Marius Vollmer
-     Mikael Djurfeldt
 
 Contributors since the last release:
 
-       Greg Harvey
        Jost Boekemeier
+       Greg Harvey
 
 For fixes or providing information which led to a fix:
 
@@ -19,11 +19,12 @@ For fixes or providing information which led to a fix:
        Brad Knotwell
    Matthias Köppe
       Bruce Korb
+       Ralf Mattes
       Shuji Narazaki
     Nicolas Neuss
     Han-Wen Nienhuys
       David Pirotte
-    William Webber
+     Julian Satchell
     Dale P. Smith
-       Ralf Mattes
  Jacques A. Vidrine.
+    William Webber

libguile/ChangeLog

@@ -1,3 +1,13 @@
+2000-11-30  Dirk Herrmann  <D.Herrmann@tu-bs.de>
+
+	Thanks to Julian Satchell for the bug report:
+
+	* coop-threads.c (scm_join_thread):  Check whether a thread is
+	finished before trying to join it.
+
+	* coop.c (coop_aborthelp, coop_join):  When a thread finishes, its
+	stack base is not set to NULL any more.
+
 2000-11-28  Dirk Herrmann  <D.Herrmann@tu-bs.de>
 
 	* strop.c (scm_i_index):  Removed outdated comment.

libguile/coop-threads.c

@@ -377,11 +377,24 @@ scm_spawn_thread (scm_catch_body_t body, void *body_data,
 }
 
 SCM
-scm_join_thread (SCM t)
+scm_join_thread (SCM thread)
 #define FUNC_NAME s_join_thread
 {
-  SCM_VALIDATE_THREAD (1,t);
+  coop_t *thread_data;
-  coop_join (SCM_THREAD_DATA (t));
+  SCM_VALIDATE_THREAD (1, thread);
+  /* Dirk:FIXME:: SCM_THREAD_DATA is a handle for a thread.  It may be that a
+   * certain thread implementation uses a value of 0 as a valid thread handle.
+   * With the following code, this thread would always be considered finished.
+   */
+  /* Dirk:FIXME:: With preemptive threading, a thread may finish immediately
+   * after SCM_THREAD_DATA is read.  Thus, it must be guaranteed that the
+   * handle remains valid until the thread-object is garbage collected, or
+   * a mutex has to be used for reading and modifying SCM_THREAD_DATA.
+   */
+  thread_data = SCM_THREAD_DATA (thread);
+  if (thread_data)
+    /* The thread is still alive */
+    coop_join (thread_data);
   return SCM_BOOL_T;
 }
 #undef FUNC_NAME

libguile/coop.c

@@ -40,7 +40,7 @@
  * If you do not wish that, delete this exception notice.  */
 
 
-/* $Id: coop.c,v 1.25 2000-04-21 14:16:30 mdj Exp $ */
+/* $Id: coop.c,v 1.26 2000-11-30 10:26:44 dirk Exp $ */
 
 /* Cooperative thread library, based on QuickThreads */
 
@@ -698,11 +698,6 @@ coop_aborthelp (qt_t *sp, void *old, void *null)
 {
   coop_t *oldthread = (coop_t *) old;
 
-#if 0
-  /* Marking old->base NULL indicates that this thread is dead */
-  oldthread->base = NULL;
-#endif
-
   if (oldthread->specific)
     free (oldthread->specific);
 #ifndef GUILE_PTHREAD_COMPAT
@@ -721,10 +716,6 @@ coop_join(coop_t *t)
 {
   coop_t *old, *newthread;
   
-  /* Check if t is already finished */
-  if (t->base == NULL)
-    return;
-
   /* Create a join list if necessary */
   if (t->joining == NULL)
     {