diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
index 7e828b69b0f..3dfa2cc6caf 100644
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -708,7 +708,8 @@ Connection objects usually created using :func:`Pipe` -- see also
       Send an object to the other end of the connection which should be read
       using :meth:`recv`.
 
-      The object must be picklable.
+      The object must be picklable.  Very large pickles (approximately 32 MB+,
+      though it depends on the OS) may raise a ValueError exception.
 
    .. method:: recv()
 
@@ -740,7 +741,9 @@ Connection objects usually created using :func:`Pipe` -- see also
       complete message.
 
       If *offset* is given then data is read from that position in *buffer*.  If
-      *size* is given then that many bytes will be read from buffer.
+      *size* is given then that many bytes will be read from buffer.  Very large
+      buffers (approximately 32 MB+, though it depends on the OS) may raise a
+      ValueError exception
 
    .. method:: recv_bytes([maxlength])
 
@@ -834,6 +837,12 @@ object -- see :ref:`multiprocessing-managers`.
 .. class:: Event()
 
    A clone of :class:`threading.Event`.
+   This method returns the state of the internal semaphore on exit, so it
+   will always return ``True`` except if a timeout is given and the operation
+   times out.
+
+   .. versionchanged:: 2.7
+      Previously, the method always returned ``None``.
 
 .. class:: Lock()
 
diff --git a/Lib/multiprocessing/synchronize.py b/Lib/multiprocessing/synchronize.py
index 08d7c5deb5c..8e994df6296 100644
--- a/Lib/multiprocessing/synchronize.py
+++ b/Lib/multiprocessing/synchronize.py
@@ -301,5 +301,10 @@ class Event(object):
                 self._flag.release()
             else:
                 self._cond.wait(timeout)
+
+            if self._flag.acquire(False):
+                self._flag.release()
+                return True
+            return False
         finally:
             self._cond.release()
diff --git a/Lib/test/test_multiprocessing.py b/Lib/test/test_multiprocessing.py
index be108b1d30f..69309ba5c1d 100644
--- a/Lib/test/test_multiprocessing.py
+++ b/Lib/test/test_multiprocessing.py
@@ -750,20 +750,22 @@ class _TestEvent(BaseTestCase):
 
         # Removed temporaily, due to API shear, this does not
         # work with threading._Event objects. is_set == isSet
-        #self.assertEqual(event.is_set(), False)
+        self.assertEqual(event.is_set(), False)
 
-        self.assertEqual(wait(0.0), None)
+        # Removed, threading.Event.wait() will return the value of the __flag
+        # instead of None. API Shear with the semaphore backed mp.Event
+        self.assertEqual(wait(0.0), False)
         self.assertTimingAlmostEqual(wait.elapsed, 0.0)
-        self.assertEqual(wait(TIMEOUT1), None)
+        self.assertEqual(wait(TIMEOUT1), False)
         self.assertTimingAlmostEqual(wait.elapsed, TIMEOUT1)
 
         event.set()
 
         # See note above on the API differences
-        # self.assertEqual(event.is_set(), True)
-        self.assertEqual(wait(), None)
+        self.assertEqual(event.is_set(), True)
+        self.assertEqual(wait(), True)
         self.assertTimingAlmostEqual(wait.elapsed, 0.0)
-        self.assertEqual(wait(TIMEOUT1), None)
+        self.assertEqual(wait(TIMEOUT1), True)
         self.assertTimingAlmostEqual(wait.elapsed, 0.0)
         # self.assertEqual(event.is_set(), True)
 
@@ -772,7 +774,7 @@ class _TestEvent(BaseTestCase):
         #self.assertEqual(event.is_set(), False)
 
         self.Process(target=self._test_event, args=(event,)).start()
-        self.assertEqual(wait(), None)
+        self.assertEqual(wait(), True)
 
 #
 #
diff --git a/Modules/_multiprocessing/connection.h b/Modules/_multiprocessing/connection.h
index 581beacf9f6..2ee5368ef37 100644
--- a/Modules/_multiprocessing/connection.h
+++ b/Modules/_multiprocessing/connection.h
@@ -139,8 +139,12 @@ connection_sendbytes(ConnectionObject *self, PyObject *args)
 	res = conn_send_string(self, buffer + offset, size);
 
 	PyBuffer_Release(&pbuffer);
-	if (res < 0)
-		return mp_SetError(PyExc_IOError, res);
+	if (res < 0) {
+		if (PyErr_Occurred())
+			return NULL;
+		else
+			return mp_SetError(PyExc_IOError, res);
+	}
 
 	Py_RETURN_NONE;
 }
diff --git a/Modules/_multiprocessing/multiprocessing.c b/Modules/_multiprocessing/multiprocessing.c
index b18f71499af..afa25994699 100644
--- a/Modules/_multiprocessing/multiprocessing.c
+++ b/Modules/_multiprocessing/multiprocessing.c
@@ -8,6 +8,12 @@
 
 #include "multiprocessing.h"
 
+#ifdef SCM_RIGHTS
+	#define HAVE_FD_TRANSFER 1
+#else
+	#define HAVE_FD_TRANSFER 0
+#endif
+
 PyObject *create_win32_namespace(void);
 
 PyObject *pickle_dumps, *pickle_loads, *pickle_protocol;
@@ -257,7 +263,7 @@ PyInit__multiprocessing(void)
 	Py_INCREF(&ConnectionType);	
 	PyModule_AddObject(module, "Connection", (PyObject*)&ConnectionType);
 
-#if defined(MS_WINDOWS) || HAVE_SEM_OPEN
+#if defined(MS_WINDOWS) || defined(HAVE_SEM_OPEN)
 	/* Add SemLock type to module */
 	if (PyType_Ready(&SemLockType) < 0)
 		return NULL;
diff --git a/Modules/_multiprocessing/multiprocessing.h b/Modules/_multiprocessing/multiprocessing.h
index 4f4f9d735e7..f8750d21540 100644
--- a/Modules/_multiprocessing/multiprocessing.h
+++ b/Modules/_multiprocessing/multiprocessing.h
@@ -27,7 +27,7 @@
 #  include <sys/socket.h>
 #  include <sys/uio.h>
 #  include <arpa/inet.h>             /* htonl() and ntohl() */
-#  if HAVE_SEM_OPEN
+#  ifdef HAVE_SEM_OPEN
 #    include <semaphore.h>
      typedef sem_t *SEM_HANDLE;
 #  endif
@@ -45,13 +45,18 @@
  * Issue 3110 - Solaris does not define SEM_VALUE_MAX
  */
 #ifndef SEM_VALUE_MAX
-#  ifdef _SEM_VALUE_MAX
-#    define SEM_VALUE_MAX _SEM_VALUE_MAX
-#  else
-#    define SEM_VALUE_MAX INT_MAX
-#  endif
+	#if defined(HAVE_SYSCONF) && defined(_SC_SEM_VALUE_MAX)
+		# define SEM_VALUE_MAX sysconf(_SC_SEM_VALUE_MAX)
+	#elif defined(_SEM_VALUE_MAX)
+		# define SEM_VALUE_MAX _SEM_VALUE_MAX
+	#elif definef(_POSIX_SEM_VALUE_MAX)
+		# define SEM_VALUE_MAX _POSIX_SEM_VALUE_MAX
+	#else
+		# define SEM_VALUE_MAX INT_MAX
+	#endif
 #endif
 
+
 /*
  * Make sure Py_ssize_t available
  */
diff --git a/Modules/_multiprocessing/pipe_connection.c b/Modules/_multiprocessing/pipe_connection.c
index 27e79dda7d4..66947c838f2 100644
--- a/Modules/_multiprocessing/pipe_connection.c
+++ b/Modules/_multiprocessing/pipe_connection.c
@@ -23,6 +23,12 @@ conn_send_string(ConnectionObject *conn, char *string, size_t length)
 	Py_BEGIN_ALLOW_THREADS
 	ret = WriteFile(conn->handle, string, length, &amount_written, NULL);
 	Py_END_ALLOW_THREADS
+
+	if (ret == 0 && GetLastError() == ERROR_NO_SYSTEM_RESOURCES) {
+		PyErr_Format(PyExc_ValueError, "Cannnot send %" PY_FORMAT_SIZE_T "d bytes over connection", length);
+		return MP_STANDARD_ERROR;
+	}
+
 	return ret ? MP_SUCCESS : MP_STANDARD_ERROR;
 }
 
diff --git a/Modules/_multiprocessing/semaphore.c b/Modules/_multiprocessing/semaphore.c
index 40bd7c3c88c..c0944c95c0e 100644
--- a/Modules/_multiprocessing/semaphore.c
+++ b/Modules/_multiprocessing/semaphore.c
@@ -197,11 +197,11 @@ semlock_release(SemLockObject *self, PyObject *args)
 #define SEM_GETVALUE(sem, pval) sem_getvalue(sem, pval)
 #define SEM_UNLINK(name) sem_unlink(name)
 
-#if HAVE_BROKEN_SEM_UNLINK
+#ifndef HAVE_SEM_UNLINK
 #  define sem_unlink(name) 0
 #endif
 
-#if !HAVE_SEM_TIMEDWAIT
+#ifndef HAVE_SEM_TIMEDWAIT
 #  define sem_timedwait(sem,deadline) sem_timedwait_save(sem,deadline,_save)
 
 int
@@ -348,7 +348,7 @@ semlock_release(SemLockObject *self, PyObject *args)
 		}
 		assert(self->count == 1);
 	} else {
-#if HAVE_BROKEN_SEM_GETVALUE
+#ifdef HAVE_BROKEN_SEM_GETVALUE
 		/* We will only check properly the maxvalue == 1 case */
 		if (self->maxvalue == 1) {
 			/* make sure that already locked */
@@ -494,7 +494,7 @@ semlock_ismine(SemLockObject *self)
 static PyObject *
 semlock_getvalue(SemLockObject *self)
 {
-#if HAVE_BROKEN_SEM_GETVALUE
+#ifdef HAVE_BROKEN_SEM_GETVALUE
 	PyErr_SetNone(PyExc_NotImplementedError);
 	return NULL;
 #else
@@ -512,7 +512,7 @@ semlock_getvalue(SemLockObject *self)
 static PyObject *
 semlock_iszero(SemLockObject *self)
 {
-#if HAVE_BROKEN_SEM_GETVALUE
+#ifdef HAVE_BROKEN_SEM_GETVALUE
 	if (sem_trywait(self->handle) < 0) {
 		if (errno == EAGAIN)
 			Py_RETURN_TRUE;
diff --git a/configure b/configure
index 25242fed4f3..f5d7352bed0 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.in Revision: 70732 .
+# From configure.in Revision: 71261 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.61 for python 3.1.
 #
@@ -16259,6 +16259,10 @@ echo "${ECHO_T}MACHDEP_OBJS" >&6; }
 
 
 
+
+
+
+
 
 
 
@@ -16271,7 +16275,8 @@ for ac_func in alarm setitimer getitimer bind_textdomain_codeset chown \
  kill killpg lchmod lchown lstat mkfifo mknod mktime \
  mremap nice pathconf pause plock poll pthread_init \
  putenv readlink realpath \
- select setegid seteuid setgid \
+ select sem_open sem_timedwait sem_getvalue sem_unlink setegid seteuid \
+ setgid \
  setlocale setregid setreuid setsid setpgid setpgrp setuid setvbuf snprintf \
  sigaction siginterrupt sigrelse strftime strlcpy \
  sysconf tcgetpgrp tcsetpgrp tempnam timegm times tmpfile tmpnam tmpnam_r \
@@ -21692,6 +21697,86 @@ _ACEOF
 
 fi
 
+# Multiprocessing check for broken sem_getvalue
+{ echo "$as_me:$LINENO: checking for broken sem_getvalue" >&5
+echo $ECHO_N "checking for broken sem_getvalue... $ECHO_C" >&6; }
+if test "$cross_compiling" = yes; then
+  { { echo "$as_me:$LINENO: error: cannot run test program while cross compiling
+See \`config.log' for more details." >&5
+echo "$as_me: error: cannot run test program while cross compiling
+See \`config.log' for more details." >&2;}
+   { (exit 1); exit 1; }; }
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <semaphore.h>
+#include <sys/stat.h>
+
+int main(void){
+  sem_t *a = sem_open("/autoconf", O_CREAT, S_IRUSR|S_IWUSR, 0);
+  int count;
+  int res;
+  if(a==SEM_FAILED){
+    perror("sem_open");
+    return 1;
+
+  }
+  res = sem_getvalue(a, &count);
+  sem_close(a);
+  return res==-1 ? 1 : 0;
+}
+
+
+_ACEOF
+rm -f 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>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && { ac_try='./conftest$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 $ac_status); }; }; then
+  { echo "$as_me:$LINENO: result: no" >&5
+echo "${ECHO_T}no" >&6; }
+else
+  echo "$as_me: program exited with status $ac_status" >&5
+echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+( exit $ac_status )
+{ echo "$as_me:$LINENO: result: yes" >&5
+echo "${ECHO_T}yes" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_BROKEN_SEM_GETVALUE 1
+_ACEOF
+
+
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
+fi
+
+
 
 # On FreeBSD 6.2, it appears that tanh(-0.) returns 0. instead of
 # -0. on some architectures.
diff --git a/configure.in b/configure.in
index aed3e144159..40fa044ba86 100644
--- a/configure.in
+++ b/configure.in
@@ -2388,7 +2388,8 @@ AC_CHECK_FUNCS(alarm setitimer getitimer bind_textdomain_codeset chown \
  kill killpg lchmod lchown lstat mkfifo mknod mktime \
  mremap nice pathconf pause plock poll pthread_init \
  putenv readlink realpath \
- select setegid seteuid setgid \
+ select sem_open sem_timedwait sem_getvalue sem_unlink setegid seteuid \
+ setgid \
  setlocale setregid setreuid setsid setpgid setpgrp setuid setvbuf snprintf \
  sigaction siginterrupt sigrelse strftime strlcpy \
  sysconf tcgetpgrp tcsetpgrp tempnam timegm times tmpfile tmpnam tmpnam_r \
@@ -3108,6 +3109,33 @@ then
   [Define if arithmetic is subject to x87-style double rounding issue])
 fi
 
+# Multiprocessing check for broken sem_getvalue
+AC_MSG_CHECKING(for broken sem_getvalue)
+AC_TRY_RUN([
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <semaphore.h>
+#include <sys/stat.h>
+
+int main(void){
+  sem_t *a = sem_open("/autoconf", O_CREAT, S_IRUSR|S_IWUSR, 0);
+  int count;
+  int res;
+  if(a==SEM_FAILED){
+    perror("sem_open");
+    return 1;
+
+  }
+  res = sem_getvalue(a, &count);
+  sem_close(a);
+  return res==-1 ? 1 : 0;
+}
+]
+,AC_MSG_RESULT(no),
+ AC_MSG_RESULT(yes)
+  AC_DEFINE(HAVE_BROKEN_SEM_GETVALUE, 1, define to 1 if your sem_getvalue is broken.)
+)
 
 # On FreeBSD 6.2, it appears that tanh(-0.) returns 0. instead of
 # -0. on some architectures.
diff --git a/pyconfig.h.in b/pyconfig.h.in
index db7f9dd61c1..40067f6ef82 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -74,6 +74,9 @@
 /* Define if pthread_sigmask() does not work on your system. */
 #undef HAVE_BROKEN_PTHREAD_SIGMASK
 
+/* define to 1 if your sem_getvalue is broken. */
+#undef HAVE_BROKEN_SEM_GETVALUE
+
 /* Define this if you have the type _Bool. */
 #undef HAVE_C99_BOOL
 
@@ -505,6 +508,18 @@
 /* Define to 1 if you have the `select' function. */
 #undef HAVE_SELECT
 
+/* Define to 1 if you have the `sem_getvalue' function. */
+#undef HAVE_SEM_GETVALUE
+
+/* Define to 1 if you have the `sem_open' function. */
+#undef HAVE_SEM_OPEN
+
+/* Define to 1 if you have the `sem_timedwait' function. */
+#undef HAVE_SEM_TIMEDWAIT
+
+/* Define to 1 if you have the `sem_unlink' function. */
+#undef HAVE_SEM_UNLINK
+
 /* Define to 1 if you have the `setegid' function. */
 #undef HAVE_SETEGID
 
diff --git a/setup.py b/setup.py
index 3c251724350..29dc59ee656 100644
--- a/setup.py
+++ b/setup.py
@@ -988,56 +988,29 @@ class PyBuildExt(build_ext):
             libraries = ['ws2_32']
 
         elif platform == 'darwin':          # Mac OSX
-            macros = dict(
-                HAVE_SEM_OPEN=1,
-                HAVE_SEM_TIMEDWAIT=0,
-                HAVE_FD_TRANSFER=1,
-                HAVE_BROKEN_SEM_GETVALUE=1
-                )
+            macros = dict()
             libraries = []
 
         elif platform == 'cygwin':          # Cygwin
-            macros = dict(
-                HAVE_SEM_OPEN=1,
-                HAVE_SEM_TIMEDWAIT=1,
-                HAVE_FD_TRANSFER=0,
-                HAVE_BROKEN_SEM_UNLINK=1
-                )
+            macros = dict()
             libraries = []
 
         elif platform in ('freebsd4', 'freebsd5', 'freebsd6', 'freebsd7', 'freebsd8'):
             # FreeBSD's P1003.1b semaphore support is very experimental
             # and has many known problems. (as of June 2008)
-            macros = dict(                  # FreeBSD
-                HAVE_SEM_OPEN=0,
-                HAVE_SEM_TIMEDWAIT=0,
-                HAVE_FD_TRANSFER=1,
-                )
+            macros = dict()
             libraries = []
 
         elif platform.startswith('openbsd'):
-            macros = dict(                  # OpenBSD
-                HAVE_SEM_OPEN=0,            # Not implemented
-                HAVE_SEM_TIMEDWAIT=0,
-                HAVE_FD_TRANSFER=1,
-                )
+            macros = dict()
             libraries = []
 
         elif platform.startswith('netbsd'):
-            macros = dict(                  # at least NetBSD 5
-                HAVE_SEM_OPEN=1,
-                HAVE_SEM_TIMEDWAIT=0,
-                HAVE_FD_TRANSFER=1,
-                HAVE_BROKEN_SEM_GETVALUE=1
-                )
+            macros = dict()
             libraries = []
 
         else:                                   # Linux and other unices
-            macros = dict(
-                HAVE_SEM_OPEN=1,
-                HAVE_SEM_TIMEDWAIT=1,
-                HAVE_FD_TRANSFER=1
-                )
+            macros = dict()
             libraries = ['rt']
 
         if platform == 'win32':
@@ -1052,8 +1025,7 @@ class PyBuildExt(build_ext):
             multiprocessing_srcs = [ '_multiprocessing/multiprocessing.c',
                                      '_multiprocessing/socket_connection.c'
                                    ]
-
-            if macros.get('HAVE_SEM_OPEN', False):
+            if sysconfig.get_config_var('HAVE_SEM_OPEN'):
                 multiprocessing_srcs.append('_multiprocessing/semaphore.c')
 
         if sysconfig.get_config_var('WITH_THREAD'):