* __scm.h (USE_THREADS, GUILE_ISELECT): Define when

SCM_DEBUG_DEPRECATED.  Removed their use thru-out Guile.

20 files changed, 26 insertions, 284 deletions

diff --git a/guile-readline/readline.c b/guile-readline/readline.c
index 6fda528d3..89fa66ff5 100644
--- a/guile-readline/readline.c
+++ b/guile-readline/readline.c
@@ -148,9 +148,7 @@ redisplay ()
 }
 
 static int in_readline = 0;
-#ifdef USE_THREADS
 static SCM reentry_barrier_mutex;
-#endif
 
 static SCM internal_readline (SCM text);
 static SCM handle_error (void *data, SCM tag, SCM args);
@@ -227,17 +225,13 @@ static void
 reentry_barrier ()
 {
   int reentryp = 0;
-#ifdef USE_THREADS
   /* We should rather use scm_try_mutex when it becomes available */
   scm_lock_mutex (reentry_barrier_mutex);
-#endif
   if (in_readline)
     reentryp = 1;
   else
     ++in_readline;
-#ifdef USE_THREADS
   scm_unlock_mutex (reentry_barrier_mutex);
-#endif
   if (reentryp)
     scm_misc_error (s_scm_readline, "readline is not reentrant", SCM_EOL);
 }
@@ -576,9 +570,7 @@ scm_init_readline ()
   rl_pre_input_hook = sigwinch_enable_restart;
 #endif
 
-#ifdef USE_THREADS
   reentry_barrier_mutex = scm_permanent_object (scm_make_mutex ());
-#endif
   scm_init_opts (scm_readline_options,
 		 scm_readline_opts,
 		 SCM_N_READLINE_OPTIONS);
diff --git a/libguile.h b/libguile.h
index 85db31c48..5d014d61b 100644
--- a/libguile.h
+++ b/libguile.h
@@ -1,7 +1,7 @@
 #ifndef SCM_LIBGUILE_H
 #define SCM_LIBGUILE_H
 
-/* Copyright (C) 1995,1996,1997,1998,2000,2001 Free Software Foundation, Inc.
+/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2002 Free Software Foundation, Inc.
  * 
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -129,9 +129,7 @@ extern "C" {
 #include "libguile/debug.h"
 #include "libguile/stacks.h"
 #endif
-#ifdef USE_THREADS
 #include "libguile/threads.h"
-#endif
 #include "libguile/inline.h"
 
 #ifdef __cplusplus
diff --git a/libguile/__scm.h b/libguile/__scm.h
index c7f2b1d58..5190e2c1d 100644
--- a/libguile/__scm.h
+++ b/libguile/__scm.h
@@ -94,9 +94,6 @@
  * These may be defined or undefined.
  */
 
-/* Old async mechanism */
-/* #define GUILE_OLD_ASYNC_CLICK */
-
 /* #define GUILE_DEBUG_FREELIST */
 
 /* All the number support there is.
@@ -151,6 +148,15 @@
 # define SCM_API extern
 #endif
 
+#if defined (SCM_ENABLE_DEPRECATED)
+
+/* These options are always active.
+ */
+#define USE_THREADS
+#define GUILE_ISELECT
+
+#endif
+
 
 
 /* What did the configure script discover about the outside world?  */
@@ -400,12 +406,6 @@ typedef long SCM_STACKITEM;
 #endif
 
 
-#ifndef USE_THREADS
-#define SCM_CRITICAL_SECTION_START
-#define SCM_CRITICAL_SECTION_END
-#define SCM_THREAD_SWITCHING_CODE
-#endif
-
 #define SCM_ASYNC_TICK /*fixme* should change names */ \
 do { \
   if (scm_root->pending_asyncs) \
diff --git a/libguile/_scm.h b/libguile/_scm.h
index 2df982b2a..42870e787 100644
--- a/libguile/_scm.h
+++ b/libguile/_scm.h
@@ -74,10 +74,7 @@
 #include "libguile/numbers.h"	/* Everyone deals with fixnums.  */
 #include "libguile/symbols.h"	/* For length, chars, values, miscellany.  */
 #include "libguile/boolean.h"	/* Everyone wonders about the truth.  */
-#ifdef USE_THREADS		
-#include "libguile/threads.h"	/* The cooperative thread package does
-				   switching at async ticks.  */
-#endif
+#include "libguile/threads.h"	/* You are not alone. */
 #include "libguile/snarf.h"	/* Everyone snarfs. */
 #include "libguile/variable.h"
 #include "libguile/modules.h"
diff --git a/libguile/async.c b/libguile/async.c
index 56b2f1776..d68be47f5 100644
--- a/libguile/async.c
+++ b/libguile/async.c
@@ -248,7 +248,6 @@ SCM_DEFINE (scm_system_async_mark_for_thread, "system-async-mark", 1, 1, 0,
 	    "signal handlers.")
 #define FUNC_NAME s_scm_system_async_mark_for_thread
 {
-#ifdef USE_THREADS
   if (SCM_UNBNDP (thread))
     thread = scm_current_thread ();
   else
@@ -259,9 +258,6 @@ SCM_DEFINE (scm_system_async_mark_for_thread, "system-async-mark", 1, 1, 0,
     }
   scm_i_queue_async_cell (scm_cons (proc, SCM_BOOL_F),
 			  scm_i_thread_root (thread));
-#else
-  scm_i_queue_async_cell (scm_cons (proc, SCM_BOOL_F), scm_root);
-#endif
   return SCM_UNSPECIFIED;
 }
 #undef FUNC_NAME
diff --git a/libguile/coop-defs.h b/libguile/coop-defs.h
index 424a0134e..716f24d66 100644
--- a/libguile/coop-defs.h
+++ b/libguile/coop-defs.h
@@ -59,9 +59,7 @@
 #  endif
 # endif
 
-#ifdef GUILE_ISELECT
 #include "libguile/iselect.h"
-#endif
 
 #if HAVE_WINSOCK2_H
 #include <winsock2.h>
@@ -106,7 +104,6 @@ typedef struct coop_t {
 
   SCM handle;            /* SCM handle, protected via scm_all_threads. */
 
-#ifdef GUILE_ISELECT
   int nfds;
   SELECT_TYPE *readfds;
   SELECT_TYPE *writefds;
@@ -115,9 +112,6 @@ typedef struct coop_t {
   struct timeval wakeup_time;	/* Time to stop sleeping */
   int _errno;
   int retval;
-#else
-  time_t wakeup_time;    /* Time to stop sleeping */
-#endif
 
 #ifdef GUILE_PTHREAD_COMPAT
   pthread_t dummy_thread;
@@ -203,10 +197,9 @@ SCM_API size_t scm_thread_count;
    iselect.h, but they use coop_t, defined above, which uses things
    defined in iselect.h.  Basically, we're making at best a flailing
    (and failing) attempt at modularity here, and I don't have time to
-   rethink this at the moment.  This code awaits a Hero.  --JimB */
-#ifdef GUILE_ISELECT
+   rethink this at the moment.  This code awaits a Hero.  --JimB
+ */
 SCM_API void coop_timeout_qinsert (coop_q_t *, coop_t *);
-#endif
 SCM_API coop_t *coop_next_runnable_thread (void);
 SCM_API coop_t *coop_wait_for_runnable_thread_now (struct timeval *);
 SCM_API coop_t *coop_wait_for_runnable_thread (void);
diff --git a/libguile/coop-threads.h b/libguile/coop-threads.h
index 98afebef9..ad18a1c6d 100644
--- a/libguile/coop-threads.h
+++ b/libguile/coop-threads.h
@@ -3,7 +3,7 @@
 #ifndef SCM_COOP_THREADS_H
 #define SCM_COOP_THREADS_H
 
-/* Copyright (C) 1996,1997,1998,2000 Free Software Foundation, Inc.
+/* Copyright (C) 1996,1997,1998,2000, 2002 Free Software Foundation, Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -112,15 +112,13 @@ SCM_API coop_t *coop_qget (coop_q_t *);
 SCM_API void coop_qput (coop_q_t *, coop_t *);
 SCM_API void *coop_sleephelp (qt_t *, void *, void *);
 
-#ifdef GUILE_ISELECT
 SCM_API coop_t *coop_wait_for_runnable_thread ();
-#endif
 
 SCM_API coop_q_t coop_global_runq;	/* A queue of runable threads. */
 SCM_API coop_q_t coop_global_sleepq;
 SCM_API coop_q_t coop_tmp_queue;
 SCM_API coop_q_t coop_global_allq;	/* A queue of all threads. */
-SCM_API coop_t *coop_global_curr;       	/* Currently-executing thread. */
+SCM_API coop_t *coop_global_curr;      	/* Currently-executing thread. */
 
 #endif  /* SCM_COOP_THREADS_H */
 
diff --git a/libguile/coop.c b/libguile/coop.c
index 3b46e65ea..36653fabc 100644
--- a/libguile/coop.c
+++ b/libguile/coop.c
@@ -40,7 +40,7 @@
  * If you do not wish that, delete this exception notice.  */
 
 
-/* $Id: coop.c,v 1.32 2002-10-27 20:12:07 mvo Exp $ */
+/* $Id: coop.c,v 1.33 2002-11-03 22:05:10 mvo Exp $ */
 
 /* Cooperative thread library, based on QuickThreads */
 
@@ -73,13 +73,11 @@ coop_qinit (coop_q_t *q)
 
   q->t.all_prev = NULL;
   q->t.all_next = NULL;
-#ifdef GUILE_ISELECT
   q->t.nfds = 0;
   q->t.readfds = NULL;
   q->t.writefds = NULL;
   q->t.exceptfds = NULL;
   q->t.timeoutp = 0;
-#endif
 }
 
 
@@ -131,7 +129,6 @@ coop_all_qremove (coop_q_t *q, coop_t *t)
       t->all_next->all_prev = t->all_prev;
 }
 
-#ifdef GUILE_ISELECT
 /* Insert thread t into the ordered queue q.
    q is ordered after wakeup_time.  Threads which aren't sleeping but
    waiting for I/O go last into the queue. */
@@ -152,10 +149,10 @@ coop_timeout_qinsert (coop_q_t *q, coop_t *t)
   if (t->next == &q->t)
     q->tail = t;
 }
-#endif
 
+
 
-/* Thread routines. */
+/* Thread routines. */
 
 coop_q_t coop_global_runq;	/* A queue of runable threads. */
 coop_q_t coop_global_sleepq;	/* A queue of sleeping threads. */
@@ -230,7 +227,6 @@ coop_init ()
    and there are sleeping threads - wait until one wakes up. Otherwise,
    return NULL. */
 
-#ifndef GUILE_ISELECT
 coop_t *
 coop_next_runnable_thread()
 {
@@ -260,7 +256,6 @@ coop_next_runnable_thread()
 
   return t;
 }
-#endif
 
 void
 coop_start()
@@ -333,13 +328,9 @@ coop_mutex_lock (coop_m *m)
       /* Record the current top-of-stack before going to sleep */
       coop_global_curr->top = &old;
 
-#ifdef GUILE_ISELECT
       newthread = coop_wait_for_runnable_thread();
       if (newthread == coop_global_curr)
 	coop_abort ();
-#else
-      newthread = coop_next_runnable_thread();
-#endif
       old = coop_global_curr;
       coop_global_curr = newthread;
       QT_BLOCK (coop_yieldhelp, old, &(m->waiting), newthread->sp);
@@ -417,13 +408,9 @@ coop_condition_variable_wait_mutex (coop_c *c, coop_m *m)
     {
       m->owner = NULL;
       /*fixme* Should we really wait here?  Isn't it OK just to proceed? */
-#ifdef GUILE_ISELECT
       newthread = coop_wait_for_runnable_thread();
       if (newthread == coop_global_curr)
 	coop_abort ();
-#else
-      newthread = coop_next_runnable_thread();
-#endif
     }
   coop_global_curr->top = &old;
   old = coop_global_curr;
@@ -457,16 +444,11 @@ coop_condition_variable_timed_wait_mutex (coop_c *c,
   else
     {
       m->owner = NULL;
-#ifdef GUILE_ISELECT
       coop_global_curr->timeoutp = 1;
       coop_global_curr->wakeup_time.tv_sec = abstime->tv_sec;
       coop_global_curr->wakeup_time.tv_usec = abstime->tv_nsec / 1000;
       coop_timeout_qinsert (&coop_global_sleepq, coop_global_curr);
       t = coop_wait_for_runnable_thread();
-#else
-      /*fixme* Implement!*/
-      t = coop_next_runnable_thread();
-#endif
     }
   if (t != coop_global_curr)
     {
@@ -712,15 +694,11 @@ coop_abort ()
       free (coop_global_curr->joining);
     }
 
-#ifdef GUILE_ISELECT
   scm_I_am_dead = 1;
   do {
     newthread = coop_wait_for_runnable_thread();
   } while (newthread == coop_global_curr);
   scm_I_am_dead = 0;
-#else
-  newthread = coop_next_runnable_thread();
-#endif
   coop_all_qremove (&coop_global_allq, coop_global_curr);
   old = coop_global_curr;
   coop_global_curr = newthread;
@@ -758,13 +736,9 @@ coop_join(coop_t *t)
       coop_qinit((coop_q_t *) t->joining);
     }
 
-#ifdef GUILE_ISELECT
   newthread = coop_wait_for_runnable_thread();
   if (newthread == coop_global_curr)
     return;
-#else
-  newthread = coop_next_runnable_thread();
-#endif
   old = coop_global_curr;
   coop_global_curr = newthread;
   QT_BLOCK (coop_yieldhelp, old, (coop_q_t *) t->joining, newthread->sp);
@@ -780,13 +754,8 @@ coop_yield()
 
   /* There may be no other runnable threads. Return if this is the 
      case. */
-#if GUILE_ISELECT
   if (newthread == coop_global_curr)
       return;
-#else
-  if (newthread == NULL)
-      return;
-#endif
 
   old = coop_global_curr;
 
@@ -815,8 +784,6 @@ coop_sleephelp (qt_t *sp, void *old, void *blockq)
   return NULL;
 }
 
-#ifdef GUILE_ISELECT
-
 unsigned long 
 scm_thread_usleep (unsigned long usec)
 {
@@ -841,43 +808,6 @@ scm_thread_sleep (unsigned long sec)
   return slept > sec ? 0 : sec - slept;
 }
 
-#else /* GUILE_ISELECT */
-
-unsigned long
-scm_thread_sleep (unsigned long s)
-{
-  coop_t *newthread, *old;
-  time_t now = time (NULL);
-  coop_global_curr->wakeup_time = now + s;
-
-  /* Put the current thread on the sleep queue */
-  coop_qput (&coop_global_sleepq, coop_global_curr);
-
-  newthread = coop_next_runnable_thread();
-
-  /* If newthread is the same as the sleeping thread, do nothing */
-  if (newthread == coop_global_curr)
-    return s;
-
-  old = coop_global_curr;
-
-  coop_global_curr = newthread;
-  QT_BLOCK (coop_sleephelp, old, NULL, newthread->sp);
-
-  return s;
-}
-
-unsigned long 
-scm_thread_usleep (unsigned long usec)
-{
-  /* We're so cheap.  */
-  scm_thread_sleep (usec / 1000000);
-  return 0;  /* Maybe we should calculate actual time slept,
-		but this is faster... :) */
-}
-
-#endif /* GUILE_ISELECT */
-
 /*
   Local Variables:
   c-file-style: "gnu"
diff --git a/libguile/debug.h b/libguile/debug.h
index 90dbee02f..3656c87a8 100644
--- a/libguile/debug.h
+++ b/libguile/debug.h
@@ -126,10 +126,6 @@ typedef struct scm_t_debug_frame
   scm_t_debug_info *info;
 } scm_t_debug_frame;
 
-#ifndef USE_THREADS
-SCM_API scm_t_debug_frame *scm_last_debug_frame;
-#endif
-
 #define SCM_EVALFRAME    (0L << 11)
 #define SCM_APPLYFRAME   (1L << 11)
 #define SCM_VOIDFRAME    (3L << 11)
diff --git a/libguile/eval.c b/libguile/eval.c
index 699f9fc4a..e775a0ce8 100644
--- a/libguile/eval.c
+++ b/libguile/eval.c
@@ -167,8 +167,6 @@ scm_ilookup (SCM iloc, SCM env)
   return SCM_CARLOC (SCM_CDR (er));
 }
 
-#ifdef USE_THREADS
-
 /* The Lookup Car Race
     - by Eva Luator
 
@@ -242,17 +240,10 @@ scm_ilookup (SCM iloc, SCM env)
    for NULL.  I think I've found the only places where this
    applies. */
 
-#endif /* USE_THREADS */
-
 SCM_SYMBOL (scm_unbound_variable_key, "unbound-variable");
 
-#ifdef USE_THREADS
 static SCM *
 scm_lookupcar1 (SCM vloc, SCM genv, int check)
-#else
-SCM *
-scm_lookupcar (SCM vloc, SCM genv, int check)
-#endif
 {
   SCM env = genv;
   register SCM *al, fl, var = SCM_CAR (vloc);
@@ -268,10 +259,8 @@ scm_lookupcar (SCM vloc, SCM genv, int check)
 	    {
 	      if (SCM_EQ_P (fl, var))
 	      {
-#ifdef USE_THREADS
 		if (! SCM_EQ_P (SCM_CAR (vloc), var))
 		  goto race;
-#endif
 		SCM_SET_CELL_WORD_0 (vloc, SCM_UNPACK (iloc) + SCM_ICDR);
 		return SCM_CDRLOC (*al);
 	      }
@@ -286,10 +275,8 @@ scm_lookupcar (SCM vloc, SCM genv, int check)
 		  env = SCM_EOL;
 		  goto errout;
 		}
-#ifdef USE_THREADS
 	      if (!SCM_EQ_P (SCM_CAR (vloc), var))
 		goto race;
-#endif
 	      SCM_SETCAR (vloc, iloc);
 	      return SCM_CARLOC (*al);
 	    }
@@ -333,7 +320,6 @@ scm_lookupcar (SCM vloc, SCM genv, int check)
 	  }
       }
 
-#ifdef USE_THREADS
     if (!SCM_EQ_P (SCM_CAR (vloc), var))
       {
 	/* Some other thread has changed the very cell we are working
@@ -352,14 +338,12 @@ scm_lookupcar (SCM vloc, SCM genv, int check)
 	   the dispatch on the car of the form. */
 	return NULL;
       }
-#endif /* USE_THREADS */
 
     SCM_SETCAR (vloc, real_var);
     return SCM_VARIABLE_LOC (real_var);
   }
 }
 
-#ifdef USE_THREADS
 SCM *
 scm_lookupcar (SCM vloc, SCM genv, int check)
 {
@@ -368,7 +352,6 @@ scm_lookupcar (SCM vloc, SCM genv, int check)
     abort ();
   return loc;
 }
-#endif
 
 #define unmemocar scm_unmemocar
 
@@ -1238,7 +1221,6 @@ scm_macroexp (SCM x, SCM env)
   if (!SCM_SYMBOLP (orig_sym))
     return x;
 
-#ifdef USE_THREADS
   {
     SCM *proc_ptr = scm_lookupcar1 (x, env, 0);
     if (proc_ptr == NULL)
@@ -1248,9 +1230,6 @@ scm_macroexp (SCM x, SCM env)
       }
     proc = *proc_ptr;
   }
-#else
-  proc = *scm_lookupcar (x, env, 0);
-#endif
   
   /* Only handle memoizing macros.  `Acros' and `macros' are really
      special forms and should not be evaluated here. */
@@ -1692,10 +1671,6 @@ SCM (*scm_ceval_ptr) (SCM x, SCM env);
  * any stack swaps.
  */
 
-#ifndef USE_THREADS
-scm_t_debug_frame *scm_last_debug_frame;
-#endif
-
 /* scm_debug_eframe_size is the number of slots available for pseudo
  * stack frames at each real stack frame.
  */
@@ -1950,9 +1925,7 @@ start:
 	}
     }
 #endif
-#if defined (USE_THREADS) || defined (DEVAL)
 dispatch:
-#endif
   SCM_TICK;
   switch (SCM_TYP7 (x))
     {
@@ -2692,7 +2665,6 @@ dispatch:
       if (SCM_SYMBOLP (SCM_CAR (x)))
 	{
 	  SCM orig_sym = SCM_CAR (x);
-#ifdef USE_THREADS
 	  {
 	    SCM *location = scm_lookupcar1 (x, env, 1);
 	    if (location == NULL)
@@ -2702,9 +2674,6 @@ dispatch:
 	      }
 	    proc = *location;
 	  }
-#else
-	  proc = *scm_lookupcar (x, env, 1);
-#endif
 
 	  if (SCM_IMP (proc))
 	    {
diff --git a/libguile/feature.c b/libguile/feature.c
index 55d25f1c6..5f25810a6 100644
--- a/libguile/feature.c
+++ b/libguile/feature.c
@@ -117,11 +117,9 @@ scm_init_feature()
 #ifndef CHEAP_CONTINUATIONS
   scm_add_feature ("full-continuation");
 #endif
-#ifdef USE_THREADS
 #ifndef USE_NULL_THREADS
   scm_add_feature ("threads");
 #endif
-#endif
   
   scm_c_define ("char-code-limit", SCM_MAKINUM (SCM_CHAR_CODE_LIMIT));
 
diff --git a/libguile/filesys.c b/libguile/filesys.c
index b1c757725..7248bbe9f 100644
--- a/libguile/filesys.c
+++ b/libguile/filesys.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1996,1997,1998,1999,2000,2001 Free Software Foundation, Inc.
+/* Copyright (C) 1996,1997,1998,1999,2000,2001, 2002 Free Software Foundation, Inc.
  * 
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -1230,14 +1230,9 @@ SCM_DEFINE (scm_select, "select", 3, 2, 0,
     }
 
   {
-#ifdef GUILE_ISELECT
     int rv = scm_internal_select (max_fd + 1,
 				  &read_set, &write_set, &except_set,
 				  time_ptr);
-#else
-    int rv = select (max_fd + 1,
-		     &read_set, &write_set, &except_set, time_ptr);
-#endif
     if (rv < 0)
       SCM_SYSERROR;
   }
diff --git a/libguile/fports.c b/libguile/fports.c
index 2fe9aa059..0a0c121c7 100644
--- a/libguile/fports.c
+++ b/libguile/fports.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001 Free Software Foundation, Inc.
+/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2002 Free Software Foundation, Inc.
  * 
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -530,7 +530,6 @@ fport_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
   return 1;
 }
 
-#ifdef GUILE_ISELECT
 /* thread-local block for input on fport's fdes.  */
 static void
 fport_wait_for_input (SCM port)
@@ -555,7 +554,6 @@ fport_wait_for_input (SCM port)
 	while (n == -1 && errno == EINTR);
     }
 }
-#endif
 
 static void fport_flush (SCM port);
 
@@ -568,9 +566,7 @@ fport_fill_input (SCM port)
   scm_t_port *pt = SCM_PTAB_ENTRY (port);
   scm_t_fport *fp = SCM_FSTREAM (port);
 
-#ifdef GUILE_ISELECT
   fport_wait_for_input (port);
-#endif
   SCM_SYSCALL (count = read (fp->fdes, pt->read_buf, pt->read_buf_size));
   if (count == -1)
     scm_syserror ("fport_fill_input");
diff --git a/libguile/gc-mark.c b/libguile/gc-mark.c
index 56ccd57f1..b65ab7aa8 100644
--- a/libguile/gc-mark.c
+++ b/libguile/gc-mark.c
@@ -110,34 +110,9 @@ scm_mark_all (void)
   
   scm_i_clear_mark_space ();
   
-#ifndef USE_THREADS
-
-  /* Mark objects on the C stack. */
-  SCM_FLUSH_REGISTER_WINDOWS;
-  /* This assumes that all registers are saved into the jmp_buf */
-  setjmp (scm_save_regs_gc_mark);
-  scm_mark_locations ((SCM_STACKITEM *) scm_save_regs_gc_mark,
-		      (   (size_t) (sizeof (SCM_STACKITEM) - 1 +
-				       sizeof scm_save_regs_gc_mark)
-			  / sizeof (SCM_STACKITEM)));
-
-  {
-    unsigned long stack_len = scm_stack_size (scm_stack_base);
-#ifdef SCM_STACK_GROWS_UP
-    scm_mark_locations (scm_stack_base, stack_len);
-#else
-    scm_mark_locations (scm_stack_base - stack_len, stack_len);
-#endif
-  }
-  SCM_MARK_BACKING_STORE();
-
-#else /* USE_THREADS */
-
   /* Mark every thread's stack and registers */
   scm_threads_mark_stacks ();
 
-#endif /* USE_THREADS */
-
   j = SCM_NUM_PROTECTS;
   while (j--)
     scm_gc_mark (scm_sys_protects[j]);
@@ -161,11 +136,6 @@ scm_mark_all (void)
    * in different phases of GC
    */
   scm_mark_subr_table ();
-
-
-#ifndef USE_THREADS
-  scm_gc_mark (scm_root->handle);
-#endif
 }
 
 /* {Mark/Sweep}
diff --git a/libguile/goops.c b/libguile/goops.c
index da6b1878a..1b78f0ad5 100644
--- a/libguile/goops.c
+++ b/libguile/goops.c
@@ -1477,9 +1477,7 @@ SCM_DEFINE (scm_sys_invalidate_class, "%invalidate-class", 1, 0, 0,
 static scm_t_bits **hell;
 static long n_hell = 1;		/* one place for the evil one himself */
 static long hell_size = 4;
-#ifdef USE_THREADS
 static SCM hell_mutex;
-#endif
 
 static long
 burnin (SCM o)
@@ -1495,9 +1493,7 @@ static void
 go_to_hell (void *o)
 {
   SCM obj = SCM_PACK ((scm_t_bits) o);
-#ifdef USE_THREADS
   scm_lock_mutex (hell_mutex);
-#endif
   if (n_hell == hell_size)
     {
       long new_size = 2 * hell_size;
@@ -1505,21 +1501,15 @@ go_to_hell (void *o)
       hell_size = new_size;
     }
   hell[n_hell++] = SCM_STRUCT_DATA (obj);
-#ifdef USE_THREADS
   scm_unlock_mutex (hell_mutex);
-#endif
 }
 
 static void
 go_to_heaven (void *o)
 {
-#ifdef USE_THREADS
   scm_lock_mutex (hell_mutex);
-#endif
   hell[burnin (SCM_PACK ((scm_t_bits) o))] = hell[--n_hell];
-#ifdef USE_THREADS
   scm_unlock_mutex (hell_mutex);
-#endif
 }
 
 
@@ -1955,7 +1945,6 @@ scm_m_atdispatch (SCM xorig, SCM env)
 #undef FUNC_NAME
 
 
-#ifdef USE_THREADS
 static void
 lock_cache_mutex (void *m)
 {
@@ -1969,7 +1958,6 @@ unlock_cache_mutex (void *m)
   SCM mutex = SCM_PACK ((scm_t_bits) m);
   scm_unlock_mutex (mutex);
 }
-#endif
 
 static SCM
 call_memoize_method (void *a)
@@ -1991,16 +1979,12 @@ SCM
 scm_memoize_method (SCM x, SCM args)
 {
   SCM gf = SCM_CAR (scm_last_pair (x));
-#ifdef USE_THREADS
   return scm_internal_dynamic_wind (
     lock_cache_mutex,
     call_memoize_method,
     unlock_cache_mutex,
     (void *) SCM_UNPACK (scm_cons2 (gf, x, args)),
     (void *) SCM_UNPACK (SCM_SLOT (gf, scm_si_cache_mutex)));
-#else
-  return call_memoize_method ((void *) SCM_UNPACK (scm_cons2 (gf, x, args)));
-#endif
 }
 
 /******************************************************************************
@@ -2037,16 +2021,11 @@ SCM_DEFINE (scm_make, "make",  0, 0, 1,
 
   if (class == scm_class_generic || class == scm_class_generic_with_setter)
     {
-#ifdef USE_THREADS
       z = scm_make_struct (class, SCM_INUM0,
 			   scm_list_4 (SCM_EOL,
 				       SCM_INUM0,
 				       SCM_BOOL_F,
 				       scm_make_mutex ()));
-#else
-      z = scm_make_struct (class, SCM_INUM0,
-			   scm_list_3 (SCM_EOL, SCM_INUM0, SCM_BOOL_F));
-#endif
       scm_set_procedure_property_x (z, scm_sym_name,
 				    scm_get_keyword (k_name,
 						     args,
@@ -2194,11 +2173,7 @@ create_standard_classes (void)
   SCM amethod_slots = scm_list_1 (scm_list_3 (scm_str2symbol ("slot-definition"),
 					      k_init_keyword,
 					      k_slot_definition));
-#ifdef USE_THREADS
   SCM mutex_slot = scm_list_1 (scm_str2symbol ("make-mutex"));
-#else
-  SCM mutex_slot = SCM_BOOL_F;
-#endif
   SCM gf_slots = scm_list_4 (scm_str2symbol ("methods"),
 			     scm_list_3 (scm_str2symbol ("n-specialized"),
 					 k_init_value,
@@ -2695,9 +2670,7 @@ scm_init_goops_builtins (void)
   list_of_no_method = scm_permanent_object (scm_list_1 (sym_no_method));
 
   hell = scm_malloc (hell_size);
-#ifdef USE_THREADS
   hell_mutex = scm_permanent_object (scm_make_mutex ());
-#endif
 
   create_basic_classes ();
   create_standard_classes ();
diff --git a/libguile/init.c b/libguile/init.c
index 393ff5fd9..ae077b88f 100644
--- a/libguile/init.c
+++ b/libguile/init.c
@@ -83,9 +83,7 @@
 #include "libguile/hash.h"
 #include "libguile/hashtab.h"
 #include "libguile/hooks.h"
-#ifdef GUILE_ISELECT
 #include "libguile/iselect.h"
-#endif
 #include "libguile/ioext.h"
 #include "libguile/keywords.h"
 #include "libguile/lang.h"
@@ -465,12 +463,10 @@ scm_init_guile_1 (SCM_STACKITEM *base)
   scm_init_variable ();           /* all bindings need variables */
   scm_init_continuations ();
   scm_init_root ();		  /* requires continuations */
-#ifdef USE_THREADS
   scm_init_threads (base);
-#endif
   start_stack (base);
   scm_init_gsubr ();
-  scm_init_thread_procs ();    /* Requires gsubrs */
+  scm_init_thread_procs ();       /* requires gsubrs */
   scm_init_procprop ();
   scm_init_environments ();
   scm_init_feature ();
@@ -497,9 +493,7 @@ scm_init_guile_1 (SCM_STACKITEM *base)
   scm_init_properties ();
   scm_init_hooks ();            /* Requires smob_prehistory */
   scm_init_gc ();		/* Requires hooks, async */
-#ifdef GUILE_ISELECT
   scm_init_iselect ();
-#endif
   scm_init_ioext ();
   scm_init_keywords ();
   scm_init_list ();
diff --git a/libguile/inline.h b/libguile/inline.h
index 1b919cf07..419c9f0bc 100644
--- a/libguile/inline.h
+++ b/libguile/inline.h
@@ -136,7 +136,6 @@ scm_cell (scm_t_bits car, scm_t_bits cdr)
   SCM_GC_SET_CELL_WORD (z, 1, cdr);
   SCM_GC_SET_CELL_WORD (z, 0, car);
 
-#ifdef USE_THREADS
 #if !defined(USE_COOP_THREADS) && !defined(USE_NULL_THREADS) && !defined(USE_COPT_THREADS)
   /* When we are using preemtive threads, we might need to make
      sure that the initial values for the slots are protected until
@@ -145,7 +144,6 @@ scm_cell (scm_t_bits car, scm_t_bits cdr)
 #error review me
   scm_remember_upto_here_1 (SCM_PACK (cdr));
 #endif
-#endif
 
 
 #if (SCM_DEBUG_CELL_ACCESSES == 1)
@@ -187,7 +185,6 @@ scm_double_cell (scm_t_bits car, scm_t_bits cbr,
   SCM_GC_SET_CELL_WORD (z, 3, cdr);
   SCM_GC_SET_CELL_WORD (z, 0, car);
 
-#ifdef USE_THREADS
 #if !defined(USE_COOP_THREADS) && !defined(USE_NULL_THREADS) && !defined(USE_COPT_THREADS)
   /* When we are using non-cooperating threads, we might need to make
      sure that the initial values for the slots are protected until
@@ -196,7 +193,6 @@ scm_double_cell (scm_t_bits car, scm_t_bits cbr,
 #error review me
   scm_remember_upto_here_3 (SCM_PACK (cbr), SCM_PACK (ccr), SCM_PACK (cdr));
 #endif
-#endif
 
 
 #if (SCM_DEBUG_CELL_ACCESSES == 1)
diff --git a/libguile/root.c b/libguile/root.c
index 7c5a26c93..041875a42 100644
--- a/libguile/root.c
+++ b/libguile/root.c
@@ -60,10 +60,6 @@ SCM scm_sys_protects[SCM_NUM_PROTECTS];
 
 scm_t_bits scm_tc16_root;
 
-#ifndef USE_THREADS
-struct scm_root_state *scm_root;
-#endif
-
 
 
 static SCM
diff --git a/libguile/root.h b/libguile/root.h
index 2795b171e..22a32b893 100644
--- a/libguile/root.h
+++ b/libguile/root.h
@@ -124,22 +124,15 @@ typedef struct scm_root_state
 #define scm_rootcont			(scm_root->rootcont)
 #define scm_dynwinds			(scm_root->dynwinds)
 #define scm_progargs			(scm_root->progargs)
-#ifdef USE_THREADS
 #define scm_last_debug_frame		(scm_root->last_debug_frame)
-#endif
 #define scm_exitval 			(scm_root->exitval)
 #define scm_cur_inp			(scm_root->cur_inp)
 #define scm_cur_outp			(scm_root->cur_outp)
 #define scm_cur_errp			(scm_root->cur_errp)
 #define scm_cur_loadp			(scm_root->cur_loadp)
 
-#ifdef USE_THREADS
-#define scm_root ((scm_root_state *) SCM_THREAD_LOCAL_DATA)
-#define scm_set_root(new_root) SCM_SET_THREAD_LOCAL_DATA (new_root)
-#else /* USE_THREADS */
-SCM_API struct scm_root_state *scm_root;
-#define scm_set_root(new_root) (scm_root = (new_root))
-#endif /* USE_THREADS */
+#define scm_root                ((scm_root_state *) SCM_THREAD_LOCAL_DATA)
+#define scm_set_root(new_root)  SCM_SET_THREAD_LOCAL_DATA (new_root)
 
 
 
diff --git a/libguile/scmsigs.c b/libguile/scmsigs.c
index b0c0e6548..35e7c5154 100644
--- a/libguile/scmsigs.c
+++ b/libguile/scmsigs.c
@@ -63,19 +63,6 @@
 #include <sys/time.h>
 #endif
 
-/* The thread system has its own sleep and usleep functions.  */
-#ifndef USE_THREADS
-
-#if defined(MISSING_SLEEP_DECL)
-int sleep ();
-#endif
-
-#if defined(HAVE_USLEEP) && defined(MISSING_USLEEP_DECL)
-int usleep ();
-#endif
-
-#endif
-
 #ifdef __MINGW32__
 #include <windows.h>
 #define alarm(sec) (0)
@@ -351,7 +338,6 @@ SCM_DEFINE (scm_sigaction_for_thread, "sigaction", 1, 3, 0,
   sigemptyset (&action.sa_mask);
 #endif
 
-#ifdef USE_THREADS
   if (SCM_UNBNDP (thread))
     thread = scm_current_thread ();
   else
@@ -360,9 +346,6 @@ SCM_DEFINE (scm_sigaction_for_thread, "sigaction", 1, 3, 0,
       if (scm_c_thread_exited_p (thread))
 	SCM_MISC_ERROR ("thread has already exited", SCM_EOL);
     }
-#else
-  thread = SCM_BOOL_F;
-#endif
 
   SCM_DEFER_INTS;
   old_handler = SCM_VECTOR_REF(*signal_handlers, csig);
@@ -647,44 +630,23 @@ SCM_DEFINE (scm_sleep, "sleep", 1, 0, 0,
 {
   unsigned long j;
   SCM_VALIDATE_INUM_MIN (1, i,0);
-#ifdef USE_THREADS
   j = scm_thread_sleep (SCM_INUM(i));
-#else
-  j = sleep (SCM_INUM(i));
-#endif
   return scm_ulong2num (j);
 }
 #undef FUNC_NAME
 
-#if defined(USE_THREADS) || defined(HAVE_USLEEP) || defined(__MINGW32__)
 SCM_DEFINE (scm_usleep, "usleep", 1, 0, 0,
            (SCM i),
 	    "Sleep for I microseconds.  @code{usleep} is not available on\n"
 	    "all platforms.")
 #define FUNC_NAME s_scm_usleep
 {
+  unsigned long j;
   SCM_VALIDATE_INUM_MIN (1, i,0);
-
-#ifdef USE_THREADS
-  /* If we have threads, we use the thread system's sleep function.  */
-  {
-    unsigned long j = scm_thread_usleep (SCM_INUM (i));
-    return scm_ulong2num (j);
-  }
-#else
-#ifdef USLEEP_RETURNS_VOID
-  usleep (SCM_INUM (i));
-  return SCM_INUM0;
-#else
-  {
-    int j = usleep (SCM_INUM (i));
-    return SCM_MAKINUM (j);
-  }
-#endif
-#endif
+  j = scm_thread_usleep (SCM_INUM (i));
+  return scm_ulong2num (j);
 }
 #undef FUNC_NAME
-#endif /* USE_THREADS || HAVE_USLEEP || __MINGW32__ */
 
 SCM_DEFINE (scm_raise, "raise", 1, 0, 0,
            (SCM sig),