Implemented mp_process_yield (Built on Dan Corkill's patches)

msvc/ecl-threads.def

@@ -1073,6 +1073,7 @@ EXPORTS
 	mp_make_process
 	mp_process_active_p
 	mp_process_enable
+	mp_process_yield
 	;mp_process_interrupt
 	mp_process_kill
 	mp_process_name

msvc/ecl/config.h.msvc6

@@ -211,6 +211,8 @@ typedef unsigned int uint32_t;
 #define HAVE_LONG_LONG 1
 /* the tzset() function gets the current time zone			*/
 #define HAVE_TZSET 1
+/* whether we have sched_yield() that gives priority to other threads	*/
+/* #undef HAVE_SCHED_YIELD */
 
 /* what characters are used to mark beginning of new line		*/
 #define ECL_NEWLINE_IS_CRLF 1

src/c/symbols_list.h

@@ -1504,6 +1504,7 @@ cl_symbols[] = {
 {MP_ "MAKE-PROCESS", MP_ORDINARY, mp_make_process, -1, OBJNULL},
 {MP_ "PROCESS-ACTIVE-P", MP_ORDINARY, mp_process_active_p, 1, OBJNULL},
 {MP_ "PROCESS-ENABLE", MP_ORDINARY, mp_process_enable, 1, OBJNULL},
+{MP_ "PROCESS-YIELD", MP_ORDINARY, mp_process_yield, 0, OBJNULL},
 {MP_ "PROCESS-KILL", MP_ORDINARY, mp_process_kill, 1, OBJNULL},
 {MP_ "PROCESS-NAME", MP_ORDINARY, mp_process_name, 1, OBJNULL},
 {MP_ "PROCESS-PRESET", MP_ORDINARY, mp_process_preset, -1, OBJNULL},

src/c/symbols_list2.h

@@ -1504,6 +1504,7 @@ cl_symbols[] = {
 {MP_ "MAKE-PROCESS","mp_make_process"},
 {MP_ "PROCESS-ACTIVE-P","mp_process_active_p"},
 {MP_ "PROCESS-ENABLE","mp_process_enable"},
+{MP_ "PROCESS-YIELD","mp_process_yield"},
 {MP_ "PROCESS-KILL","mp_process_kill"},
 {MP_ "PROCESS-NAME","mp_process_name"},
 {MP_ "PROCESS-PRESET","mp_process_preset"},

src/c/threads.d

@@ -26,6 +26,9 @@
 #ifdef HAVE_GETTIMEOFDAY
 # include <sys/time.h>
 #endif
+#ifdef HAVE_SCHED_YIELD
+# include <sched.h>
+#endif
 
 #ifndef WITH___THREAD
 static pthread_key_t cl_env_key;
@@ -207,6 +210,17 @@ mp_process_kill(cl_object process)
 	@(return Ct)
 }
 
+cl_object
+mp_process_yield(void)
+{
+#ifdef HAVE_SCHED_YIELD
+	sched_yield();
+#else
+	sleep(0); /* Use sleep(0) to yield to a >= priority thread */
+#endif
+	@(return)
+}
+
 cl_object
 mp_process_enable(cl_object process)
 {

src/c/threads_win32.d

@@ -18,6 +18,9 @@
 #include <signal.h>
 #include <ecl/ecl.h>
 #include <ecl/internal.h>
+#ifdef HAVE_SCHED_YIELD
+# include <sched.h>
+#endif
 
 /*
  * We have to put this explicit definition here because Boehm GC
@@ -219,6 +222,17 @@ mp_process_kill(cl_object process)
 	return mp_interrupt_process(process, @'mp::exit-process');
 }
 
+cl_object
+mp_process_yield(void)
+{
+#ifdef HAVE_SCHED_YIELD
+	sched_yield();
+#else
+	sleep(0); /* Use sleep(0) to yield to a >= priority thread */
+#endif
+	@(return)
+}
+
 cl_object
 mp_process_enable(cl_object process)
 {

src/configure

@@ -11775,6 +11775,117 @@ done
 
 
 
+for ac_func in sched_yield
+do
+as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
+{ echo "$as_me:$LINENO: checking for $ac_func" >&5
+echo $ECHO_N "checking for $ac_func... $ECHO_C" >&6; }
+if { as_var=$as_ac_var; eval "test \"\${$as_var+set}\" = set"; }; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+/* Define $ac_func to an innocuous variant, in case <limits.h> declares $ac_func.
+   For example, HP-UX 11i <limits.h> declares gettimeofday.  */
+#define $ac_func innocuous_$ac_func
+
+/* System header to define __stub macros and hopefully few prototypes,
+    which can conflict with char $ac_func (); below.
+    Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
+    <limits.h> exists even on freestanding compilers.  */
+
+#ifdef __STDC__
+# include <limits.h>
+#else
+# include <assert.h>
+#endif
+
+#undef $ac_func
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char $ac_func ();
+/* The GNU C library defines this for functions which it implements
+    to always fail with ENOSYS.  Some functions are actually named
+    something starting with __ and the normal name is an alias.  */
+#if defined __stub_$ac_func || defined __stub___$ac_func
+choke me
+#endif
+
+int
+main ()
+{
+return $ac_func ();
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+	 { ac_try='test -z "$ac_c_werror_flag" || test ! -s conftest.err'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+	 { ac_try='test -s conftest$ac_exeext'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  eval "$as_ac_var=yes"
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	eval "$as_ac_var=no"
+fi
+
+rm -f core conftest.err conftest.$ac_objext \
+      conftest$ac_exeext conftest.$ac_ext
+fi
+ac_res=`eval echo '${'$as_ac_var'}'`
+	       { echo "$as_me:$LINENO: result: $ac_res" >&5
+echo "${ECHO_T}$ac_res" >&6; }
+if test `eval echo '${'$as_ac_var'}'` = yes; then
+  cat >>confdefs.h <<_ACEOF
+#define `echo "HAVE_$ac_func" | $as_tr_cpp` 1
+_ACEOF
+
+fi
+done
+
+
+
 
 if test ${with_cxx} = "no" ; then
   ECL_CC=${CC}

src/configure.in

@@ -446,6 +446,8 @@ AC_CHECK_FUNCS( [nanosleep alarm times isnanf select setenv putenv] \
 AC_CHECK_FUNCS( [expf logf sqrtf cosf sinf tanf sinhf coshf tanhf] \
 		[floorf ceilf fabsf frexpf ldexpf])
 
+AC_CHECK_FUNCS( [sched_yield] )
+
 dnl =====================================================================
 dnl Checks for system services
 

src/h/config.h.in

@@ -247,6 +247,8 @@ typedef unsigned @CL_FIXNUM_TYPE@ cl_hashkey;
 #undef HAVE_FABSF
 #undef HAVE_FREXPF
 #undef HAVE_LDEXPF
+/* whether we have sched_yield() that gives priority to other threads	*/
+#undef HAVE_SCHED_YIELD
 
 /*
  * we do not manage to get proper signal handling of floating point

src/h/external.h

@@ -1394,6 +1394,7 @@ extern cl_object mp_interrupt_process(cl_object process, cl_object function);
 extern cl_object mp_make_process _ARGS((cl_narg narg, ...));
 extern cl_object mp_process_active_p(cl_object process);
 extern cl_object mp_process_enable(cl_object process);
+extern cl_object mp_process_yield(void);
 extern cl_object mp_process_interrupt(cl_object process, cl_object function);
 extern cl_object mp_process_kill(cl_object process);
 extern cl_object mp_process_name(cl_object process);