Merge remote-tracking branch 'origin/4.8'

15 files changed, 505 insertions, 208 deletions

diff --git a/src/corelib/kernel/qcoreapplication.cpp b/src/corelib/kernel/qcoreapplication.cpp
index 7694a0f..dd46bc5 100644
--- a/src/corelib/kernel/qcoreapplication.cpp
+++ b/src/corelib/kernel/qcoreapplication.cpp
@@ -98,6 +98,12 @@
 #  include <taskLib.h>
 #endif
 
+#ifdef Q_OS_QNX
+#  include <sys/neutrino.h>
+#  include <pthread.h>
+#  include <sched.h>
+#endif
+
 QT_BEGIN_NAMESPACE
 
 class QMutexUnlocker
@@ -353,6 +359,22 @@ QCoreApplicationPrivate::QCoreApplicationPrivate(int &aargc, char **aargv, uint
     qt_application_thread_id = QThread::currentThreadId();
 #endif
 
+#ifdef Q_OS_QNX
+    // make the kernel attempt to emulate an instruction with a misaligned access
+    // if the attempt fails, it faults with a SIGBUS
+    int tv = -1;
+    ThreadCtl(_NTO_TCTL_ALIGN_FAULT, &tv);
+
+    // without Round Robin drawn intensive apps will hog the cpu
+    // and make the system appear frozen
+    int sched_policy;
+    sched_param param;
+    if (pthread_getschedparam(0, &sched_policy, &param) == 0 && sched_policy != SCHED_RR) {
+        sched_policy = SCHED_RR;
+        pthread_setschedparam(0, sched_policy, &param);
+    }
+#endif
+
     // note: this call to QThread::currentThread() may end up setting theMainThread!
     if (QThread::currentThread() != theMainThread)
         qWarning("WARNING: QApplication was not created in the main() thread.");
diff --git a/src/corelib/kernel/qobject.cpp b/src/corelib/kernel/qobject.cpp
index a4948c1..b88643d 100644
--- a/src/corelib/kernel/qobject.cpp
+++ b/src/corelib/kernel/qobject.cpp
@@ -1790,6 +1790,7 @@ QObjectList QObject::queryList(const char *inheritsClass,
 /*!
     \fn T qFindChild(const QObject *obj, const QString &name)
     \relates QObject
+    \overload qFindChildren()
     \obsolete
 
     This function is equivalent to
@@ -1805,6 +1806,7 @@ QObjectList QObject::queryList(const char *inheritsClass,
 /*!
     \fn QList<T> qFindChildren(const QObject *obj, const QString &name)
     \relates QObject
+    \overload qFindChildren()
     \obsolete
 
     This function is equivalent to
@@ -1834,38 +1836,6 @@ QObjectList QObject::queryList(const char *inheritsClass,
 
 /*!
     \internal
-    \fn T qFindChild(const QObject *obj, const QString &name = QString(), T dummy = 0)
-    \relates QObject
-    \overload qFindChildren()
-
-    This function is equivalent to
-    \a{obj}->\l{QObject::findChild()}{findChild}<T>(\a name).
-
-    \note This function was provided as a workaround for MSVC 6
-    which did not support member template functions. It is advised
-    to use the other form in new code.
-
-    \sa QObject::findChild()
-*/
-
-/*!
-    \internal
-    \fn QList<T> qFindChildren(const QObject *obj, const QString &name = QString(), T dummy = 0)
-    \relates QObject
-    \overload qFindChildren()
-
-    This function is equivalent to
-    \a{obj}->\l{QObject::findChildren()}{findChildren}<T>(\a name).
-
-    \note This function was provided as a workaround for MSVC 6
-    which did not support member template functions. It is advised
-    to use the other form in new code.
-
-    \sa QObject::findChildren()
-*/
-
-/*!
-    \internal
 */
 void qt_qFindChildren_helper(const QObject *parent, const QString &name, const QRegExp *re,
                              const QMetaObject &mo, QList<void*> *list)
@@ -2419,20 +2389,22 @@ int QObject::receivers(const char *signal) const
     This helper function calculates signal and method index for the given
     member in the specified class.
 
-    \li If member.mobj is 0 then both signalIndex and methodIndex are set to -1.
+    \list
+    \o If member.mobj is 0 then both signalIndex and methodIndex are set to -1.
 
-    \li If specified member is not a member of obj instance class (or one of
+    \o If specified member is not a member of obj instance class (or one of
     its parent classes) then both signalIndex and methodIndex are set to -1.
+    \endlist
 
     This function is used by QObject::connect and QObject::disconnect which
     are working with QMetaMethod.
 
-    \param[out] signalIndex is set to the signal index of member. If the member
+    \a signalIndex is set to the signal index of member. If the member
     specified is not signal this variable is set to -1.
 
-    \param[out] methodIndex is set to the method index of the member. If the
-    member is not a method of the object specified by obj param this variable
-    is set to -1.
+    \a methodIndex is set to the method index of the member. If the
+    member is not a method of the object specified by the \a obj argument this
+    variable is set to -1.
 */
 void QMetaObjectPrivate::memberIndexes(const QObject *obj,
                                        const QMetaMethod &member,
@@ -2689,9 +2661,9 @@ bool QObject::connect(const QObject *sender, const char *signal,
             Qt::ConnectionType type)
     but it uses QMetaMethod to specify signal and method.
 
-    \see connect(const QObject *sender, const char *signal,
-                 const QObject *receiver, const char *method,
-                 Qt::ConnectionType type)
+    \sa connect(const QObject *sender, const char *signal,
+                const QObject *receiver, const char *method,
+                Qt::ConnectionType type)
  */
 bool QObject::connect(const QObject *sender, const QMetaMethod &signal,
                       const QObject *receiver, const QMetaMethod &method,
@@ -2987,7 +2959,7 @@ bool QObject::disconnect(const QObject *sender, const char *signal,
     In the same way 0 can be used for \a receiver in the meaning "any receiving object". In this case
     method shoud also be QMetaMethod(). \a sender parameter should be never 0.
 
-    \see disconnect(const QObject *sender, const char *signal, const QObject *receiver, const char *method)
+    \sa disconnect(const QObject *sender, const char *signal, const QObject *receiver, const char *method)
  */
 bool QObject::disconnect(const QObject *sender, const QMetaMethod &signal,
                          const QObject *receiver, const QMetaMethod &method)
diff --git a/src/corelib/kernel/qobject.h b/src/corelib/kernel/qobject.h
index d274fa3..15d81b9 100644
--- a/src/corelib/kernel/qobject.h
+++ b/src/corelib/kernel/qobject.h
@@ -345,6 +345,11 @@ public:
 };
 #endif
 
+#ifdef qdoc
+T qFindChild(const QObject *o, const QString &name = QString());
+QList<T> qFindChildren(const QObject *oobj, const QString &name = QString());
+QList<T> qFindChildren(const QObject *o, const QRegExp &re);
+#endif
 #ifdef QT_DEPRECATED
 template<typename T>
 inline QT_DEPRECATED T qFindChild(const QObject *o, const QString &name = QString())
diff --git a/src/corelib/kernel/qsharedmemory.cpp b/src/corelib/kernel/qsharedmemory.cpp
index acb6044..371974c 100644
--- a/src/corelib/kernel/qsharedmemory.cpp
+++ b/src/corelib/kernel/qsharedmemory.cpp
@@ -80,6 +80,8 @@ QSharedMemoryPrivate::makePlatformSafeKey(const QString &key,
     return result;
 #elif defined(Q_OS_SYMBIAN)
     return result.left(KMaxKernelName);
+#elif defined(QT_POSIX_IPC)
+    return QLatin1Char('/') + result;
 #else
     return QDir::tempPath() + QLatin1Char('/') + result;
 #endif
@@ -117,6 +119,9 @@ QSharedMemoryPrivate::makePlatformSafeKey(const QString &key,
   process crashes without running the QSharedMemory destructor, the
   shared memory segment survives the crash.
 
+  \o QNX: Due to possible race conditions in the POSIX IPC implementation, create()
+  should be called prior to any attach() calls (even across multiple threads).
+
   \o HP-UX: Only one attach to a shared memory segment is allowed per
   process. This means that QSharedMemory should not be used across
   multiple threads in the same process in HP-UX.
@@ -247,14 +252,14 @@ void QSharedMemory::setNativeKey(const QString &key)
     if (isAttached())
         detach();
     d->cleanHandle();
-    d->key = QString();
+    d->key.clear();
     d->nativeKey = key;
 }
 
 bool QSharedMemoryPrivate::initKey()
 {
-    if (!cleanHandle())
-        return false;
+    cleanHandle();
+
 #ifndef QT_NO_SYSTEMSEMAPHORE
     systemSemaphore.setKey(QString(), 1);
     systemSemaphore.setKey(key, 1);
@@ -285,7 +290,7 @@ bool QSharedMemoryPrivate::initKey()
         return false;
     }
 #endif
-    errorString = QString();
+    errorString.clear();
     error = QSharedMemory::NoError;
     return true;
 }
@@ -342,28 +347,24 @@ bool QSharedMemory::create(int size, AccessMode mode)
     if (!d->initKey())
         return false;
 
+    if (size <= 0) {
+        d->error = QSharedMemory::InvalidSize;
+        d->errorString = QSharedMemory::tr("%1: create size is less then 0").arg(QLatin1String("QSharedMemory::create"));
+        return false;
+    }
+
 #ifndef QT_NO_SYSTEMSEMAPHORE
 #ifndef Q_OS_WIN
     // Take ownership and force set initialValue because the semaphore
     // might have already existed from a previous crash.
     d->systemSemaphore.setKey(d->key, 1, QSystemSemaphore::Create);
 #endif
-#endif
 
-    QString function = QLatin1String("QSharedMemory::create");
-#ifndef QT_NO_SYSTEMSEMAPHORE
     QSharedMemoryLocker lock(this);
-    if (!d->key.isNull() && !d->tryLocker(&lock, function))
+    if (!d->key.isNull() && !d->tryLocker(&lock, QLatin1String("QSharedMemory::create")))
         return false;
 #endif
 
-    if (size <= 0) {
-        d->error = QSharedMemory::InvalidSize;
-        d->errorString =
-	    QSharedMemory::tr("%1: create size is less then 0").arg(function);
-        return false;
-    }
-
     if (!d->create(size))
         return false;
 
diff --git a/src/corelib/kernel/qsharedmemory_p.h b/src/corelib/kernel/qsharedmemory_p.h
index d5fafef..780e52e 100644
--- a/src/corelib/kernel/qsharedmemory_p.h
+++ b/src/corelib/kernel/qsharedmemory_p.h
@@ -70,12 +70,12 @@ namespace QSharedMemoryPrivate
 #include "private/qobject_p.h"
 
 #ifdef Q_OS_WIN
-#include <qt_windows.h>
+#  include <qt_windows.h>
 #elif defined(Q_OS_SYMBIAN)
-#include <e32std.h>
-#include <sys/types.h>
+#  include <e32std.h>
+#  include <sys/types.h>
 #else
-#include <sys/sem.h>
+#  include <sys/types.h>
 #endif
 
 QT_BEGIN_NAMESPACE
@@ -135,11 +135,13 @@ public:
             const QString &prefix = QLatin1String("qipc_sharedmemory_"));
 #ifdef Q_OS_WIN
     HANDLE handle();
+#elif defined(QT_POSIX_IPC)
+    int handle();
 #else
     key_t handle();
 #endif
     bool initKey();
-    bool cleanHandle();
+    void cleanHandle();
     bool create(int size);
     bool attach(QSharedMemory::AccessMode mode);
     bool detach();
@@ -151,7 +153,7 @@ public:
 #endif
 
 #ifndef QT_NO_SYSTEMSEMAPHORE
-    bool tryLocker(QSharedMemoryLocker *locker, const QString function) {
+    inline bool tryLocker(QSharedMemoryLocker *locker, const QString &function) {
         if (!locker->lock()) {
             errorString = QSharedMemory::tr("%1: unable to lock").arg(function);
             error = QSharedMemory::LockError;
@@ -166,6 +168,8 @@ private:
     HANDLE hand;
 #elif defined(Q_OS_SYMBIAN)
     RChunk chunk;
+#elif defined(QT_POSIX_IPC)
+    int hand;
 #else
     key_t unix_key;
 #endif
diff --git a/src/corelib/kernel/qsharedmemory_symbian.cpp b/src/corelib/kernel/qsharedmemory_symbian.cpp
index fdd513a..cd1567a 100644
--- a/src/corelib/kernel/qsharedmemory_symbian.cpp
+++ b/src/corelib/kernel/qsharedmemory_symbian.cpp
@@ -41,19 +41,21 @@
 
 #include "qsharedmemory.h"
 #include "qsharedmemory_p.h"
-#include "qsystemsemaphore.h"
+
 #include "qcore_symbian_p.h"
 #include <qdebug.h>
 
-QT_BEGIN_NAMESPACE
-
 #ifndef QT_NO_SHAREDMEMORY
 
 #define QSHAREDMEMORY_DEBUG
 
-QSharedMemoryPrivate::QSharedMemoryPrivate() : QObjectPrivate(),
-        memory(0), size(0), error(QSharedMemory::NoError),
-           systemSemaphore(QString()), lockedByMe(false)
+QT_BEGIN_NAMESPACE
+
+QSharedMemoryPrivate::QSharedMemoryPrivate()
+    : QObjectPrivate(), memory(0), size(0), error(QSharedMemory::NoError),
+#ifndef QT_NO_SYSTEMSEMAPHORE
+      systemSemaphore(QString()), lockedByMe(false)
+#endif
 {
 }
 
@@ -61,6 +63,7 @@ void QSharedMemoryPrivate::setErrorString(const QString &function, TInt errorCod
 {
     if (errorCode == KErrNone)
         return;
+
     switch (errorCode) {
     case KErrAlreadyExists:
         error = QSharedMemory::AlreadyExists;
@@ -88,40 +91,43 @@ void QSharedMemoryPrivate::setErrorString(const QString &function, TInt errorCod
 #if defined QSHAREDMEMORY_DEBUG
         qDebug() << errorString << "key" << key;
 #endif
+        break;
     }
 }
 
 key_t QSharedMemoryPrivate::handle()
 {
+    // don't allow making handles on empty keys
+    if (nativeKey.isEmpty()) {
+        error = QSharedMemory::KeyError;
+        errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::handle"));
+        return 0;
+    }
+
     // Not really cost effective to check here if shared memory is attachable, as it requires
     // exactly the same call as attaching, so always assume handle is valid and return failure
     // from attach.
     return 1;
 }
 
-bool QSharedMemoryPrivate::cleanHandle()
+void QSharedMemoryPrivate::cleanHandle()
 {
     chunk.Close();
-    return true;
 }
 
 bool QSharedMemoryPrivate::create(int size)
 {
-    QString function = QLatin1String("QSharedMemory::create");
-    if (nativeKey.isEmpty()) {
-        error = QSharedMemory::KeyError;
-        errorString = QSharedMemory::tr("%1: key error").arg(function);
+    if (!handle())
         return false;
-    }
 
     TPtrC ptr(qt_QString2TPtrC(nativeKey));
 
     TInt err = chunk.CreateGlobal(ptr, size, size);
 
-    setErrorString(function, err);
-
-    if (err != KErrNone)
+    if (err != KErrNone) {
+        setErrorString(QLatin1String("QSharedMemory::create"), err);
         return false;
+    }
 
     // Zero out the created chunk
     Mem::FillZ(chunk.Base(), chunk.Size());
@@ -133,12 +139,8 @@ bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode /* mode */)
 {
     // Grab a pointer to the memory block
     if (!chunk.Handle()) {
-        QString function = QLatin1String("QSharedMemory::handle");
-        if (nativeKey.isEmpty()) {
-            error = QSharedMemory::KeyError;
-            errorString = QSharedMemory::tr("%1: unable to make key").arg(function);
+        if (!handle())
             return false;
-        }
 
         TPtrC ptr(qt_QString2TPtrC(nativeKey));
 
@@ -147,7 +149,7 @@ bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode /* mode */)
         err = chunk.OpenGlobal(ptr, false);
 
         if (err != KErrNone) {
-            setErrorString(function, err);
+            setErrorString(QLatin1String("QSharedMemory::attach"), err);
             return false;
         }
     }
@@ -168,6 +170,6 @@ bool QSharedMemoryPrivate::detach()
     return true;
 }
 
-#endif //QT_NO_SHAREDMEMORY
-
 QT_END_NAMESPACE
+
+#endif //QT_NO_SHAREDMEMORY
diff --git a/src/corelib/kernel/qsharedmemory_unix.cpp b/src/corelib/kernel/qsharedmemory_unix.cpp
index 2bbda49..a086acd 100644
--- a/src/corelib/kernel/qsharedmemory_unix.cpp
+++ b/src/corelib/kernel/qsharedmemory_unix.cpp
@@ -43,25 +43,30 @@
 
 #include "qsharedmemory.h"
 #include "qsharedmemory_p.h"
-#include "qsystemsemaphore.h"
-#include <qdir.h>
-#include <qdebug.h>
 
-#include <errno.h>
+#include <qdebug.h>
+#include <qfile.h>
 
 #ifndef QT_NO_SHAREDMEMORY
 #include <sys/types.h>
 #include <sys/ipc.h>
+#ifndef QT_POSIX_IPC
 #include <sys/shm.h>
-#include <sys/types.h>
+#else
+#include <sys/mman.h>
 #include <sys/stat.h>
+#endif
 #include <fcntl.h>
 #include <unistd.h>
-#endif //QT_NO_SHAREDMEMORY
+#endif // QT_NO_SHAREDMEMORY
+#include <errno.h>
 
 #include "private/qcore_unix_p.h"
 
 #ifndef QT_NO_SHAREDMEMORY
+
+//#define QSHAREDMEMORY_DEBUG
+
 QT_BEGIN_NAMESPACE
 
 QSharedMemoryPrivate::QSharedMemoryPrivate()
@@ -69,7 +74,11 @@ QSharedMemoryPrivate::QSharedMemoryPrivate()
 #ifndef QT_NO_SYSTEMSEMAPHORE
       systemSemaphore(QString()), lockedByMe(false),
 #endif
+#ifndef QT_POSIX_IPC
       unix_key(0)
+#else
+      hand(0)
+#endif
 {
 }
 
@@ -78,6 +87,7 @@ void QSharedMemoryPrivate::setErrorString(const QString &function)
     // EINVAL is handled in functions so they can give better error strings
     switch (errno) {
     case EACCES:
+    case EPERM:
         errorString = QSharedMemory::tr("%1: permission denied").arg(function);
         error = QSharedMemory::PermissionDenied;
         break;
@@ -89,18 +99,25 @@ void QSharedMemoryPrivate::setErrorString(const QString &function)
         errorString = QSharedMemory::tr("%1: doesn't exist").arg(function);
         error = QSharedMemory::NotFound;
         break;
+    case EAGAIN:
     case EMFILE:
+    case ENFILE:
     case ENOMEM:
     case ENOSPC:
         errorString = QSharedMemory::tr("%1: out of resources").arg(function);
         error = QSharedMemory::OutOfResources;
         break;
+    case EOVERFLOW:
+        errorString = QSharedMemory::tr("%1: invalid size").arg(function);
+        error = QSharedMemory::InvalidSize;
+        break;
     default:
         errorString = QSharedMemory::tr("%1: unknown error %2").arg(function).arg(errno);
         error = QSharedMemory::UnknownError;
-#if defined QSHAREDMEMORY_DEBUG
+#ifdef QSHAREDMEMORY_DEBUG
         qDebug() << errorString << "key" << key << "errno" << errno << EINVAL;
 #endif
+        break;
     }
 }
 
@@ -109,6 +126,7 @@ void QSharedMemoryPrivate::setErrorString(const QString &function)
 
     If not already made create the handle used for accessing the shared memory.
 */
+#ifndef QT_POSIX_IPC
 key_t QSharedMemoryPrivate::handle()
 {
     // already made
@@ -117,26 +135,40 @@ key_t QSharedMemoryPrivate::handle()
 
     // don't allow making handles on empty keys
     if (nativeKey.isEmpty()) {
-        errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::handle:"));
+        errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::handle"));
         error = QSharedMemory::KeyError;
         return 0;
     }
 
     // ftok requires that an actual file exists somewhere
     if (!QFile::exists(nativeKey)) {
-        errorString = QSharedMemory::tr("%1: UNIX key file doesn't exist").arg(QLatin1String("QSharedMemory::handle:"));
+        errorString = QSharedMemory::tr("%1: UNIX key file doesn't exist").arg(QLatin1String("QSharedMemory::handle"));
         error = QSharedMemory::NotFound;
         return 0;
     }
 
     unix_key = ftok(QFile::encodeName(nativeKey).constData(), 'Q');
     if (-1 == unix_key) {
-        errorString = QSharedMemory::tr("%1: ftok failed").arg(QLatin1String("QSharedMemory::handle:"));
+        errorString = QSharedMemory::tr("%1: ftok failed").arg(QLatin1String("QSharedMemory::handle"));
         error = QSharedMemory::KeyError;
         unix_key = 0;
     }
     return unix_key;
 }
+#else
+int QSharedMemoryPrivate::handle()
+{
+    // don't allow making handles on empty keys
+    QString safeKey = makePlatformSafeKey(key);
+    if (safeKey.isEmpty()) {
+        errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::handle"));
+        error = QSharedMemory::KeyError;
+        return 0;
+    }
+
+    return 1;
+}
+#endif // QT_POSIX_IPC
 
 #endif // QT_NO_SHAREDMEMORY
 
@@ -149,46 +181,54 @@ key_t QSharedMemoryPrivate::handle()
     -1 error
      0 already existed
      1 created
-  */
+*/
 int QSharedMemoryPrivate::createUnixKeyFile(const QString &fileName)
 {
+#ifndef QT_POSIX_IPC
     if (QFile::exists(fileName))
         return 0;
 
     int fd = qt_safe_open(QFile::encodeName(fileName).constData(),
-            O_EXCL | O_CREAT | O_RDWR, 0640);
+                          O_EXCL | O_CREAT | O_RDWR, 0640);
     if (-1 == fd) {
         if (errno == EEXIST)
             return 0;
         return -1;
     } else {
-        close(fd);
+        qt_safe_close(fd);
     }
     return 1;
+#else
+    Q_UNUSED(fileName);
+    // nothing to do
+    return -1;
+#endif
 }
 #endif // QT_NO_SHAREDMEMORY && QT_NO_SYSTEMSEMAPHORE
 
 #ifndef QT_NO_SHAREDMEMORY
 
-bool QSharedMemoryPrivate::cleanHandle()
+void QSharedMemoryPrivate::cleanHandle()
 {
+#ifndef QT_POSIX_IPC
     unix_key = 0;
-    return true;
+#else
+    qt_safe_close(hand);
+    hand = 0;
+#endif
 }
 
 bool QSharedMemoryPrivate::create(int size)
 {
+#ifndef QT_POSIX_IPC
     // build file if needed
-    bool createdFile = false;
     int built = createUnixKeyFile(nativeKey);
     if (built == -1) {
-        errorString = QSharedMemory::tr("%1: unable to make key").arg(QLatin1String("QSharedMemory::handle:"));
+        errorString = QSharedMemory::tr("%1: unable to make key").arg(QLatin1String("QSharedMemory::create"));
         error = QSharedMemory::KeyError;
         return false;
     }
-    if (built == 1) {
-        createdFile = true;
-    }
+    bool createdFile = built == 1;
 
     // get handle
     if (!handle()) {
@@ -202,7 +242,7 @@ bool QSharedMemoryPrivate::create(int size)
         QString function = QLatin1String("QSharedMemory::create");
         switch (errno) {
         case EINVAL:
-            errorString = QSharedMemory::tr("%1: system-imposed size restrictions").arg(QLatin1String("QSharedMemory::handle"));
+            errorString = QSharedMemory::tr("%1: system-imposed size restrictions").arg(function);
             error = QSharedMemory::InvalidSize;
             break;
         default:
@@ -212,12 +252,46 @@ bool QSharedMemoryPrivate::create(int size)
             QFile::remove(nativeKey);
         return false;
     }
+#else
+    if (!handle())
+        return false;
+
+    QByteArray shmName = QFile::encodeName(makePlatformSafeKey(key));
+
+    int fd;
+    EINTR_LOOP(fd, shm_open(shmName.constData(), O_RDWR | O_CREAT | O_EXCL, 0666));
+    if (fd == -1) {
+        QString function = QLatin1String("QSharedMemory::create");
+        switch (errno) {
+        case ENAMETOOLONG:
+        case EINVAL:
+            errorString = QSharedMemory::tr("%1: bad name").arg(function);
+            error = QSharedMemory::KeyError;
+            break;
+        default:
+            setErrorString(function);
+        }
+        return false;
+    }
+
+    // the size may only be set once; ignore errors
+    int ret;
+    EINTR_LOOP(ret, ftruncate(fd, size));
+    if (ret == -1) {
+        setErrorString(QLatin1String("QSharedMemory::create (ftruncate)"));
+        qt_safe_close(fd);
+        return false;
+    }
+
+    qt_safe_close(fd);
+#endif // QT_POSIX_IPC
 
     return true;
 }
 
 bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode)
 {
+#ifndef QT_POSIX_IPC
     // grab the shared memory segment id
     int id = shmget(unix_key, 0, (mode == QSharedMemory::ReadOnly ? 0444 : 0660));
     if (-1 == id) {
@@ -241,12 +315,55 @@ bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode)
         setErrorString(QLatin1String("QSharedMemory::attach (shmctl)"));
         return false;
     }
+#else
+    QByteArray shmName = QFile::encodeName(makePlatformSafeKey(key));
+
+    int oflag = (mode == QSharedMemory::ReadOnly ? O_RDONLY : O_RDWR);
+    mode_t omode = (mode == QSharedMemory::ReadOnly ? 0444 : 0660);
+
+    EINTR_LOOP(hand, shm_open(shmName.constData(), oflag, omode));
+    if (hand == -1) {
+        QString function = QLatin1String("QSharedMemory::attach (shm_open)");
+        switch (errno) {
+        case ENAMETOOLONG:
+        case EINVAL:
+            errorString = QSharedMemory::tr("%1: bad name").arg(function);
+            error = QSharedMemory::KeyError;
+            break;
+        default:
+            setErrorString(function);
+        }
+        hand = 0;
+        return false;
+    }
+
+    // grab the size
+    QT_STATBUF st;
+    if (QT_FSTAT(hand, &st) == -1) {
+        setErrorString(QLatin1String("QSharedMemory::attach (fstat)"));
+        cleanHandle();
+        return false;
+    }
+    size = st.st_size;
+
+    // grab the memory
+    int mprot = (mode == QSharedMemory::ReadOnly ? PROT_READ : PROT_READ | PROT_WRITE);
+    memory = mmap(0, size, mprot, MAP_SHARED, hand, 0);
+    if (memory == MAP_FAILED || !memory) {
+        setErrorString(QLatin1String("QSharedMemory::attach (mmap)"));
+        cleanHandle();
+        memory = 0;
+        size = 0;
+        return false;
+    }
+#endif // QT_POSIX_IPC
 
     return true;
 }
 
 bool QSharedMemoryPrivate::detach()
 {
+#ifndef QT_POSIX_IPC
     // detach from the memory segment
     if (-1 == shmdt(memory)) {
         QString function = QLatin1String("QSharedMemory::detach");
@@ -280,7 +397,7 @@ bool QSharedMemoryPrivate::detach()
     if (shmid_ds.shm_nattch == 0) {
         // mark for removal
         if (-1 == shmctl(id, IPC_RMID, &shmid_ds)) {
-            setErrorString(QLatin1String("QSharedMemory::remove"));
+            setErrorString(QLatin1String("QSharedMemory::detach"));
             switch (errno) {
             case EINVAL:
                 return true;
@@ -293,10 +410,34 @@ bool QSharedMemoryPrivate::detach()
         if (!QFile::remove(nativeKey))
             return false;
     }
+#else
+    // detach from the memory segment
+    if (munmap(memory, size) == -1) {
+        setErrorString(QLatin1String("QSharedMemory::detach (munmap)"));
+        return false;
+    }
+    memory = 0;
+    size = 0;
+
+    // get the number of current attachments
+    int shm_nattch = 0;
+    QT_STATBUF st;
+    if (QT_FSTAT(hand, &st) == 0) {
+        // subtract 2 from linkcount: one for our own open and one for the dir entry
+        shm_nattch = st.st_nlink - 2;
+    }
+    cleanHandle();
+    // if there are no attachments then unlink the shared memory
+    if (shm_nattch == 0) {
+        QByteArray shmName = QFile::encodeName(makePlatformSafeKey(key));
+        if (shm_unlink(shmName.constData()) == -1 && errno != ENOENT)
+            setErrorString(QLatin1String("QSharedMemory::detach (shm_unlink)"));
+    }
+#endif // QT_POSIX_IPC
+
     return true;
 }
 
-
 QT_END_NAMESPACE
 
 #endif // QT_NO_SHAREDMEMORY
diff --git a/src/corelib/kernel/qsharedmemory_win.cpp b/src/corelib/kernel/qsharedmemory_win.cpp
index 3cc14fe..567214e 100644
--- a/src/corelib/kernel/qsharedmemory_win.cpp
+++ b/src/corelib/kernel/qsharedmemory_win.cpp
@@ -41,24 +41,30 @@
 
 #include "qsharedmemory.h"
 #include "qsharedmemory_p.h"
-#include "qsystemsemaphore.h"
-#include <qdebug.h>
 
-QT_BEGIN_NAMESPACE
+#include <qdebug.h>
 
 #ifndef QT_NO_SHAREDMEMORY
 
-QSharedMemoryPrivate::QSharedMemoryPrivate() : QObjectPrivate(),
-        memory(0), size(0), error(QSharedMemory::NoError),
-           systemSemaphore(QString()), lockedByMe(false), hand(0)
+//#define QSHAREDMEMORY_DEBUG
+
+QT_BEGIN_NAMESPACE
+
+QSharedMemoryPrivate::QSharedMemoryPrivate()
+    : QObjectPrivate(), memory(0), size(0), error(QSharedMemory::NoError),
+#ifndef QT_NO_SYSTEMSEMAPHORE
+      systemSemaphore(QString()), lockedByMe(false),
+#endif
+      hand(0)
 {
 }
 
 void QSharedMemoryPrivate::setErrorString(const QString &function)
 {
-    BOOL windowsError = GetLastError();
+    DWORD windowsError = GetLastError();
     if (windowsError == 0)
         return;
+
     switch (windowsError) {
     case ERROR_ALREADY_EXISTS:
         error = QSharedMemory::AlreadyExists;
@@ -89,19 +95,20 @@ void QSharedMemoryPrivate::setErrorString(const QString &function)
     default:
         errorString = QSharedMemory::tr("%1: unknown error %2").arg(function).arg(windowsError);
         error = QSharedMemory::UnknownError;
-#if defined QSHAREDMEMORY_DEBUG
+#ifdef QSHAREDMEMORY_DEBUG
         qDebug() << errorString << "key" << key;
 #endif
+        break;
     }
 }
 
 HANDLE QSharedMemoryPrivate::handle()
 {
     if (!hand) {
-        QString function = QLatin1String("QSharedMemory::handle");
+        // don't allow making handles on empty keys
         if (nativeKey.isEmpty()) {
             error = QSharedMemory::KeyError;
-            errorString = QSharedMemory::tr("%1: unable to make key").arg(function);
+            errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::handle"));
             return false;
         }
 #ifndef Q_OS_WINCE
@@ -111,43 +118,34 @@ HANDLE QSharedMemoryPrivate::handle()
         // attach as it seems.
         hand = CreateFileMapping(INVALID_HANDLE_VALUE, 0, PAGE_READWRITE, 0, 0, (wchar_t*)nativeKey.utf16());
 #endif
-        if (!hand) {
-            setErrorString(function);
-            return false;
-        }
+        if (!hand)
+            setErrorString(QLatin1String("QSharedMemory::handle"));
     }
+
     return hand;
 }
 
-bool QSharedMemoryPrivate::cleanHandle()
+void QSharedMemoryPrivate::cleanHandle()
 {
-    if (hand != 0 && !CloseHandle(hand)) {
-        hand = 0;
+    if (hand != 0 && !CloseHandle(hand))
         setErrorString(QLatin1String("QSharedMemory::cleanHandle"));
-        return false;
-    }
     hand = 0;
-    return true;
 }
 
 bool QSharedMemoryPrivate::create(int size)
 {
-    QString function = QLatin1String("QSharedMemory::create");
     if (nativeKey.isEmpty()) {
         error = QSharedMemory::KeyError;
-        errorString = QSharedMemory::tr("%1: key error").arg(function);
+        errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::create"));
         return false;
     }
 
     // Create the file mapping.
     hand = CreateFileMapping(INVALID_HANDLE_VALUE, 0, PAGE_READWRITE, 0, size, (wchar_t*)nativeKey.utf16());
-    setErrorString(function);
+    setErrorString(QLatin1String("QSharedMemory::create"));
 
     // hand is valid when it already exists unlike unix so explicitly check
-    if (error == QSharedMemory::AlreadyExists || !hand)
-        return false;
-
-    return true;
+    return !(error == QSharedMemory::AlreadyExists || !hand);
 }
 
 bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode)
@@ -167,7 +165,7 @@ bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode)
         // Windows doesn't set an error code on this one,
         // it should only be a kernel memory error.
         error = QSharedMemory::UnknownError;
-        errorString = QSharedMemory::tr("%1: size query failed").arg(QLatin1String("QSharedMemory::attach: "));
+        errorString = QSharedMemory::tr("%1: size query failed").arg(QLatin1String("QSharedMemory::attach"));
         return false;
     }
     size = info.RegionSize;
@@ -186,10 +184,11 @@ bool QSharedMemoryPrivate::detach()
     size = 0;
 
     // close handle
-    return cleanHandle();
-}
-
-#endif //QT_NO_SHAREDMEMORY
+    cleanHandle();
 
+    return true;
+}
 
 QT_END_NAMESPACE
+
+#endif // QT_NO_SHAREDMEMORY
diff --git a/src/corelib/kernel/qsystemsemaphore.cpp b/src/corelib/kernel/qsystemsemaphore.cpp
index 98ee6f4..ae30348 100644
--- a/src/corelib/kernel/qsystemsemaphore.cpp
+++ b/src/corelib/kernel/qsystemsemaphore.cpp
@@ -151,6 +151,11 @@ QT_BEGIN_NAMESPACE
   creates a new semaphore for that key and sets its resource count to
   \a initialValue.
 
+  In QNX, if the \a mode is \l {QSystemSemaphore::} {Create} and the
+  system already has a semaphore identified by \a key, that semaphore
+  will be deleted and the new one will be created for that key with
+  a resource count set to \a initialValue.
+
   In Windows and in Symbian, \a mode is ignored, and the system always tries to
   create a semaphore for the specified \a key. If the system does not
   already have a semaphore identified as \a key, it creates the
@@ -234,7 +239,7 @@ void QSystemSemaphore::setKey(const QString &key, int initialValue, AccessMode m
         return;
     d->error = NoError;
     d->errorString = QString();
-#if !defined(Q_OS_WIN) && !defined(Q_OS_SYMBIAN)
+#if !defined(Q_OS_WIN) && !defined(Q_OS_SYMBIAN) && !defined(QT_POSIX_IPC)
     // optimization to not destroy/create the file & semaphore
     if (key == d->key && mode == Create && d->createdSemaphore && d->createdFile) {
         d->initialValue = initialValue;
diff --git a/src/corelib/kernel/qsystemsemaphore_p.h b/src/corelib/kernel/qsystemsemaphore_p.h
index d4e86e8..d84d416 100644
--- a/src/corelib/kernel/qsystemsemaphore_p.h
+++ b/src/corelib/kernel/qsystemsemaphore_p.h
@@ -59,7 +59,10 @@
 
 #include "qsharedmemory_p.h"
 #ifndef Q_OS_WINCE
-#   include <sys/types.h>
+#  include <sys/types.h>
+#endif
+#ifdef QT_POSIX_IPC
+#  include <semaphore.h>
 #endif
 
 #ifdef Q_OS_SYMBIAN
@@ -70,11 +73,10 @@ QT_BEGIN_NAMESPACE
 
 class QSystemSemaphorePrivate
 {
-
 public:
     QSystemSemaphorePrivate();
 
-    QString makeKeyFileName()
+    inline QString makeKeyFileName() const
     {
         return QSharedMemoryPrivate::makePlatformSafeKey(key, QLatin1String("qipc_systemsem_"));
     }
@@ -85,6 +87,9 @@ public:
 #elif defined(Q_OS_SYMBIAN)
     int handle(QSystemSemaphore::AccessMode mode = QSystemSemaphore::Open);
     void setErrorString(const QString &function,int err = 0);
+#elif defined(QT_POSIX_IPC)
+    bool handle(QSystemSemaphore::AccessMode mode = QSystemSemaphore::Open);
+    void setErrorString(const QString &function);
 #else
     key_t handle(QSystemSemaphore::AccessMode mode = QSystemSemaphore::Open);
     void setErrorString(const QString &function);
@@ -100,11 +105,14 @@ public:
     HANDLE semaphoreLock;
 #elif defined(Q_OS_SYMBIAN)
     RSemaphore semaphore;
+#elif defined(QT_POSIX_IPC)
+    sem_t *semaphore;
+    bool createdSemaphore;
 #else
+    key_t unix_key;
     int semaphore;
     bool createdFile;
     bool createdSemaphore;
-    key_t unix_key;
 #endif
     QString errorString;
     QSystemSemaphore::SystemSemaphoreError error;
@@ -115,4 +123,3 @@ QT_END_NAMESPACE
 #endif // QT_NO_SYSTEMSEMAPHORE
 
 #endif // QSYSTEMSEMAPHORE_P_H
-
diff --git a/src/corelib/kernel/qsystemsemaphore_symbian.cpp b/src/corelib/kernel/qsystemsemaphore_symbian.cpp
index 96c19af..bb60df7 100644
--- a/src/corelib/kernel/qsystemsemaphore_symbian.cpp
+++ b/src/corelib/kernel/qsystemsemaphore_symbian.cpp
@@ -46,29 +46,32 @@
 
 #include "qcore_symbian_p.h"
 #include <e32cmn.h>
-QT_BEGIN_NAMESPACE
 
 #ifndef QT_NO_SYSTEMSEMAPHORE
 
+//#define QSYSTEMSEMAPHORE_DEBUG
+
+QT_BEGIN_NAMESPACE
+
 QSystemSemaphorePrivate::QSystemSemaphorePrivate() :
-        error(QSystemSemaphore::NoError)
+    error(QSystemSemaphore::NoError)
 {
 }
 
 void QSystemSemaphorePrivate::setErrorString(const QString &function, int err)
 {
-    if (err == KErrNone){
+    if (err == KErrNone)
         return;
-    }
+
     switch(err){
     case KErrAlreadyExists:
         errorString = QCoreApplication::tr("%1: already exists", "QSystemSemaphore").arg(function);
         error = QSystemSemaphore::AlreadyExists;
-    break;
+        break;
     case KErrNotFound:
         errorString = QCoreApplication::tr("%1: does not exist", "QSystemSemaphore").arg(function);
         error = QSystemSemaphore::NotFound;
-    break;
+        break;
     case KErrNoMemory:
     case KErrInUse:
         errorString = QCoreApplication::tr("%1: out of resources", "QSystemSemaphore").arg(function);
@@ -77,22 +80,21 @@ void QSystemSemaphorePrivate::setErrorString(const QString &function, int err)
     case KErrPermissionDenied:
         errorString = QCoreApplication::tr("%1: permission denied", "QSystemSemaphore").arg(function);
         error = QSystemSemaphore::PermissionDenied;
-    break;
-default:
-    errorString = QCoreApplication::tr("%1: unknown error %2", "QSystemSemaphore").arg(function).arg(err);
-    error = QSystemSemaphore::UnknownError;
-    }
-
-#if defined QSYSTEMSEMAPHORE_DEBUG
+        break;
+    default:
+        errorString = QCoreApplication::tr("%1: unknown error %2", "QSystemSemaphore").arg(function).arg(err);
+        error = QSystemSemaphore::UnknownError;
+#ifdef QSYSTEMSEMAPHORE_DEBUG
         qDebug() << errorString << "key" << key;
 #endif
+        break;
+    }
 }
 
 int QSystemSemaphorePrivate::handle(QSystemSemaphore::AccessMode)
 {
-    if (semaphore.Handle()) {
+    if (semaphore.Handle())
         return semaphore.Handle();
-    }
 
     // don't allow making handles on empty keys
     if (key.isEmpty())
@@ -106,12 +108,13 @@ int QSystemSemaphorePrivate::handle(QSystemSemaphore::AccessMode)
     while (err != KErrNoMemory && err != KErrNone && tryCount-- >= 0) {
         err = semaphore.CreateGlobal(name, initialValue, EOwnerProcess);
         if (err != KErrNoMemory && err != KErrNone)
-            err = semaphore.OpenGlobal(name,EOwnerProcess);
+            err = semaphore.OpenGlobal(name, EOwnerProcess);
     }
-    if (err){
-        setErrorString(QLatin1String("QSystemSemaphore::handle"),err);
+    if (err) {
+        setErrorString(QLatin1String("QSystemSemaphore::handle"), err);
         return 0;
     }
+
     return semaphore.Handle();
 }
 
@@ -125,14 +128,14 @@ bool QSystemSemaphorePrivate::modifySemaphore(int count)
     if (0 == handle())
         return false;
 
-    if (count > 0) {
+    if (count > 0)
         semaphore.Signal(count);
-    } else {
+    else
         semaphore.Wait();
-        }
+
     return true;
 }
 
-#endif //QT_NO_SYSTEMSEMAPHORE
-
 QT_END_NAMESPACE
+
+#endif // QT_NO_SYSTEMSEMAPHORE
diff --git a/src/corelib/kernel/qsystemsemaphore_unix.cpp b/src/corelib/kernel/qsystemsemaphore_unix.cpp
index 5e533e7..e060eb2 100644
--- a/src/corelib/kernel/qsystemsemaphore_unix.cpp
+++ b/src/corelib/kernel/qsystemsemaphore_unix.cpp
@@ -42,15 +42,17 @@
 #include "qsystemsemaphore.h"
 #include "qsystemsemaphore_p.h"
 
+#include <qcoreapplication.h>
 #include <qdebug.h>
 #include <qfile.h>
-#include <qcoreapplication.h>
 
 #ifndef QT_NO_SYSTEMSEMAPHORE
 
 #include <sys/types.h>
 #include <sys/ipc.h>
+#ifndef QT_POSIX_IPC
 #include <sys/sem.h>
+#endif
 #include <fcntl.h>
 #include <errno.h>
 
@@ -62,11 +64,17 @@
 #define EIDRM EINVAL
 #endif
 
+//#define QSYSTEMSEMAPHORE_DEBUG
+
 QT_BEGIN_NAMESPACE
 
 QSystemSemaphorePrivate::QSystemSemaphorePrivate() :
-        semaphore(-1), createdFile(false),
-        createdSemaphore(false), unix_key(-1), error(QSystemSemaphore::NoError)
+#ifndef QT_POSIX_IPC
+    unix_key(-1), semaphore(-1), createdFile(false),
+#else
+    semaphore(SEM_FAILED),
+#endif
+    createdSemaphore(false), error(QSystemSemaphore::NoError)
 {
 }
 
@@ -88,40 +96,49 @@ void QSystemSemaphorePrivate::setErrorString(const QString &function)
         error = QSystemSemaphore::NotFound;
         break;
     case ERANGE:
+    case ENOMEM:
     case ENOSPC:
+    case EMFILE:
+    case ENFILE:
+    case EOVERFLOW:
         errorString = QCoreApplication::translate("QSystemSemaphore", "%1: out of resources").arg(function);
         error = QSystemSemaphore::OutOfResources;
         break;
+    case ENAMETOOLONG:
+        errorString = QCoreApplication::translate("QSystemSemaphore", "%1: name error").arg(function);
+        error = QSystemSemaphore::KeyError;
+        break;
     default:
         errorString = QCoreApplication::translate("QSystemSemaphore", "%1: unknown error %2").arg(function).arg(errno);
         error = QSystemSemaphore::UnknownError;
-#if defined QSYSTEMSEMAPHORE_DEBUG
+#ifdef QSYSTEMSEMAPHORE_DEBUG
         qDebug() << errorString << "key" << key << "errno" << errno << EINVAL;
 #endif
+        break;
     }
 }
 
 /*!
     \internal
 
-    Setup unix_key
- */
+    Initialise the semaphore
+*/
+#ifndef QT_POSIX_IPC
 key_t QSystemSemaphorePrivate::handle(QSystemSemaphore::AccessMode mode)
 {
-    if (key.isEmpty()){
-        errorString = QCoreApplication::tr("%1: key is empty", "QSystemSemaphore").arg(QLatin1String("QSystemSemaphore::handle:"));
+    if (-1 != unix_key)
+        return unix_key;
+
+    if (key.isEmpty()) {
+        errorString = QCoreApplication::tr("%1: key is empty", "QSystemSemaphore").arg(QLatin1String("QSystemSemaphore::handle"));
         error = QSystemSemaphore::KeyError;
         return -1;
     }
 
     // ftok requires that an actual file exists somewhere
-    if (-1 != unix_key)
-        return unix_key;
-
-    // Create the file needed for ftok
     int built = QSharedMemoryPrivate::createUnixKeyFile(fileName);
     if (-1 == built) {
-        errorString = QCoreApplication::tr("%1: unable to make key", "QSystemSemaphore").arg(QLatin1String("QSystemSemaphore::handle:"));
+        errorString = QCoreApplication::tr("%1: unable to make key", "QSystemSemaphore").arg(QLatin1String("QSystemSemaphore::handle"));
         error = QSystemSemaphore::KeyError;
         return -1;
     }
@@ -130,7 +147,7 @@ key_t QSystemSemaphorePrivate::handle(QSystemSemaphore::AccessMode mode)
     // Get the unix key for the created file
     unix_key = ftok(QFile::encodeName(fileName).constData(), 'Q');
     if (-1 == unix_key) {
-        errorString = QCoreApplication::tr("%1: ftok failed", "QSystemSemaphore").arg(QLatin1String("QSystemSemaphore::handle:"));
+        errorString = QCoreApplication::tr("%1: ftok failed", "QSystemSemaphore").arg(QLatin1String("QSystemSemaphore::handle"));
         error = QSystemSemaphore::KeyError;
         return -1;
     }
@@ -145,17 +162,16 @@ key_t QSystemSemaphorePrivate::handle(QSystemSemaphore::AccessMode mode)
             cleanHandle();
             return -1;
         }
+        if (mode == QSystemSemaphore::Create) {
+            createdSemaphore = true;
+            createdFile = true;
+        }
     } else {
         createdSemaphore = true;
         // Force cleanup of file, it is possible that it can be left over from a crash
         createdFile = true;
     }
 
-    if (mode == QSystemSemaphore::Create) {
-        createdSemaphore = true;
-        createdFile = true;
-    }
-
     // Created semaphore so initialize its value.
     if (createdSemaphore && initialValue >= 0) {
         qt_semun init_op;
@@ -169,14 +185,63 @@ key_t QSystemSemaphorePrivate::handle(QSystemSemaphore::AccessMode mode)
 
     return unix_key;
 }
+#else
+bool QSystemSemaphorePrivate::handle(QSystemSemaphore::AccessMode mode)
+{
+    if (semaphore != SEM_FAILED)
+        return true;  // we already have a semaphore
+
+    if (fileName.isEmpty()) {
+        errorString = QCoreApplication::tr("%1: key is empty", "QSystemSemaphore").arg(QLatin1String("QSystemSemaphore::handle"));
+        error = QSystemSemaphore::KeyError;
+        return false;
+    }
+
+    QByteArray semName = QFile::encodeName(fileName);
+
+    // Always try with O_EXCL so we know whether we created the semaphore.
+    int oflag = O_CREAT | O_EXCL;
+    for (int tryNum = 0, maxTries = 1; tryNum < maxTries; ++tryNum) {
+        do {
+            semaphore = sem_open(semName.constData(), oflag, 0666, initialValue);
+        } while (semaphore == SEM_FAILED && errno == EINTR);
+        if (semaphore == SEM_FAILED && errno == EEXIST) {
+            if (mode == QSystemSemaphore::Create) {
+                if (sem_unlink(semName.constData()) == -1 && errno != ENOENT) {
+                    setErrorString(QLatin1String("QSystemSemaphore::handle (sem_unlink)"));
+                    return false;
+                }
+                // Race condition: the semaphore might be recreated before
+                // we call sem_open again, so we'll retry several times.
+                maxTries = 3;
+            } else {
+                // Race condition: if it no longer exists at the next sem_open
+                // call, we won't realize we created it, so we'll leak it later.
+                oflag &= ~O_EXCL;
+                maxTries = 2;
+            }
+        } else {
+            break;
+        }
+    }
+    if (semaphore == SEM_FAILED) {
+        setErrorString(QLatin1String("QSystemSemaphore::handle"));
+        return false;
+    }
+
+    createdSemaphore = (oflag & O_EXCL) != 0;
+    return true;
+}
+#endif // QT_POSIX_IPC
 
 /*!
     \internal
 
-    Cleanup the unix_key
- */
+    Clean up the semaphore
+*/
 void QSystemSemaphorePrivate::cleanHandle()
 {
+#ifndef QT_POSIX_IPC
     unix_key = -1;
 
     // remove the file if we made it
@@ -189,21 +254,43 @@ void QSystemSemaphorePrivate::cleanHandle()
         if (-1 != semaphore) {
             if (-1 == semctl(semaphore, 0, IPC_RMID, 0)) {
                 setErrorString(QLatin1String("QSystemSemaphore::cleanHandle"));
-#if defined QSYSTEMSEMAPHORE_DEBUG
-                qDebug() << QLatin1String("QSystemSemaphore::cleanHandle semctl failed.");
+#ifdef QSYSTEMSEMAPHORE_DEBUG
+                qDebug("QSystemSemaphore::cleanHandle semctl failed.");
 #endif
             }
             semaphore = -1;
         }
         createdSemaphore = false;
     }
+#else
+    if (semaphore != SEM_FAILED) {
+        if (sem_close(semaphore) == -1) {
+            setErrorString(QLatin1String("QSystemSemaphore::cleanHandle (sem_close)"));
+#ifdef QSYSTEMSEMAPHORE_DEBUG
+            qDebug() << QLatin1String("QSystemSemaphore::cleanHandle sem_close failed.");
+#endif
+        }
+        semaphore = SEM_FAILED;
+    }
+
+    if (createdSemaphore) {
+        if (sem_unlink(QFile::encodeName(fileName).constData()) == -1 && errno != ENOENT) {
+            setErrorString(QLatin1String("QSystemSemaphore::cleanHandle (sem_unlink)"));
+#ifdef QSYSTEMSEMAPHORE_DEBUG
+            qDebug() << QLatin1String("QSystemSemaphore::cleanHandle sem_unlink failed.");
+#endif
+        }
+        createdSemaphore = false;
+    }
+#endif // QT_POSIX_IPC
 }
 
 /*!
     \internal
- */
+*/
 bool QSystemSemaphorePrivate::modifySemaphore(int count)
 {
+#ifndef QT_POSIX_IPC
     if (-1 == handle())
         return false;
 
@@ -223,16 +310,53 @@ bool QSystemSemaphorePrivate::modifySemaphore(int count)
             return modifySemaphore(count);
         }
         setErrorString(QLatin1String("QSystemSemaphore::modifySemaphore"));
-#if defined QSYSTEMSEMAPHORE_DEBUG
+#ifdef QSYSTEMSEMAPHORE_DEBUG
         qDebug() << QLatin1String("QSystemSemaphore::modify failed") << count << semctl(semaphore, 0, GETVAL) << errno << EIDRM << EINVAL;
 #endif
         return false;
     }
+#else
+    if (!handle())
+        return false;
+
+    if (count > 0) {
+        int cnt = count;
+        do {
+            if (sem_post(semaphore) == -1) {
+                setErrorString(QLatin1String("QSystemSemaphore::modifySemaphore (sem_post)"));
+#ifdef QSYSTEMSEMAPHORE_DEBUG
+                qDebug() << QLatin1String("QSystemSemaphore::modify sem_post failed") << count << errno;
+#endif
+                // rollback changes to preserve the SysV semaphore behavior
+                for ( ; cnt < count; ++cnt) {
+                    register int res;
+                    EINTR_LOOP(res, sem_wait(semaphore));
+                }
+                return false;
+            }
+            --cnt;
+        } while (cnt > 0);
+    } else {
+        register int res;
+        EINTR_LOOP(res, sem_wait(semaphore));
+        if (res == -1) {
+            // If the semaphore was removed be nice and create it and then modifySemaphore again
+            if (errno == EINVAL || errno == EIDRM) {
+                semaphore = SEM_FAILED;
+                return modifySemaphore(count);
+            }
+            setErrorString(QLatin1String("QSystemSemaphore::modifySemaphore (sem_wait)"));
+#ifdef QSYSTEMSEMAPHORE_DEBUG
+            qDebug() << QLatin1String("QSystemSemaphore::modify sem_wait failed") << count << errno;
+#endif
+            return false;
+        }
+    }
+#endif // QT_POSIX_IPC
 
     return true;
 }
 
-
 QT_END_NAMESPACE
 
 #endif // QT_NO_SYSTEMSEMAPHORE
diff --git a/src/corelib/kernel/qsystemsemaphore_win.cpp b/src/corelib/kernel/qsystemsemaphore_win.cpp
index 30cab7e..0e9d645 100644
--- a/src/corelib/kernel/qsystemsemaphore_win.cpp
+++ b/src/corelib/kernel/qsystemsemaphore_win.cpp
@@ -44,18 +44,20 @@
 #include "qcoreapplication.h"
 #include <qdebug.h>
 
-QT_BEGIN_NAMESPACE
-        
 #ifndef QT_NO_SYSTEMSEMAPHORE
 
+//#define QSYSTEMSEMAPHORE_DEBUG
+
+QT_BEGIN_NAMESPACE
+
 QSystemSemaphorePrivate::QSystemSemaphorePrivate() :
-        semaphore(0), error(QSystemSemaphore::NoError)
+    semaphore(0), error(QSystemSemaphore::NoError)
 {
 }
 
 void QSystemSemaphorePrivate::setErrorString(const QString &function)
 {
-    BOOL windowsError = GetLastError();
+    DWORD windowsError = GetLastError();
     if (windowsError == 0)
         return;
 
@@ -72,9 +74,10 @@ void QSystemSemaphorePrivate::setErrorString(const QString &function)
     default:
         errorString = QCoreApplication::translate("QSystemSemaphore", "%1: unknown error %2").arg(function).arg(windowsError);
         error = QSystemSemaphore::UnknownError;
-#if defined QSYSTEMSEMAPHORE_DEBUG
+#ifdef QSYSTEMSEMAPHORE_DEBUG
         qDebug() << errorString << "key" << key;
 #endif
+        break;
     }
 }
 
@@ -110,7 +113,7 @@ bool QSystemSemaphorePrivate::modifySemaphore(int count)
         return false;
 
     if (count > 0) {
-	if (0 == ReleaseSemaphore(semaphore, count, 0)) {
+        if (0 == ReleaseSemaphore(semaphore, count, 0)) {
             setErrorString(QLatin1String("QSystemSemaphore::modifySemaphore"));
 #if defined QSYSTEMSEMAPHORE_DEBUG
             qDebug() << QLatin1String("QSystemSemaphore::modifySemaphore ReleaseSemaphore failed");
@@ -130,6 +133,6 @@ bool QSystemSemaphorePrivate::modifySemaphore(int count)
     return true;
 }
 
-#endif //QT_NO_SYSTEMSEMAPHORE
+#endif // QT_NO_SYSTEMSEMAPHORE
 
 QT_END_NAMESPACE
diff --git a/src/corelib/kernel/qtimer.cpp b/src/corelib/kernel/qtimer.cpp
index 3c8704c..0edcb3b 100644
--- a/src/corelib/kernel/qtimer.cpp
+++ b/src/corelib/kernel/qtimer.cpp
@@ -205,6 +205,9 @@ QTimer::~QTimer()
 
     Starts or restarts the timer with the timeout specified in \l interval.
 
+    If the timer is already running, it will be
+    \l{QTimer::stop()}{stopped} and restarted.
+
     If \l singleShot is true, the timer will be activated only once.
 */
 void QTimer::start()
@@ -218,6 +221,12 @@ void QTimer::start()
 /*!
     Starts or restarts the timer with a timeout interval of \a msec
     milliseconds.
+
+    If the timer is already running, it will be
+    \l{QTimer::stop()}{stopped} and restarted.
+
+    If \l singleShot is true, the timer will be activated only once.
+
 */
 void QTimer::start(int msec)
 {
diff --git a/src/corelib/kernel/qtranslator.cpp b/src/corelib/kernel/qtranslator.cpp
index 4504eab..d255422 100644
--- a/src/corelib/kernel/qtranslator.cpp
+++ b/src/corelib/kernel/qtranslator.cpp
@@ -600,7 +600,7 @@ static QString find_translation(const QLocale & locale,
 /*!
     \since 4.8
 
-    Loads \a filename + \a prefix + \a \l{QLocale::uiLanguages()}{ui language
+    Loads \a filename + \a prefix + \l{QLocale::uiLanguages()}{ui language
     name} + \a suffix (".qm" if the \a suffix is not specified), which may be
     an absolute file name or relative to \a directory. Returns true if the
     translation is successfully loaded; otherwise returns false.
@@ -618,7 +618,7 @@ static QString find_translation(const QLocale & locale,
     \endlist
 
     For example, an application running in the locale with the following
-    l{QLocale::uiLanguages()}{ui languages} - "es", "fr-CA", "de" might call
+    \l{QLocale::uiLanguages()}{ui languages} - "es", "fr-CA", "de" might call
     load(QLocale::system(), "foo", ".", "/opt/foolib", ".qm"). load() would
     replace '-' (dash) with '_' (underscore) in the ui language and then try to
     open the first existing readable file from this list:
@@ -637,8 +637,8 @@ static QString find_translation(const QLocale & locale,
     \o \c /opt/foolib/foo
     \endlist
 
-    For OSs where file system is case sensitive, QTranslator also tries to load
-    a lower-cased version of the locale name.
+    On operating systems where file system is case sensitive, QTranslator also
+    tries to load a lower-cased version of the locale name.
 */
 bool QTranslator::load(const QLocale & locale,
                        const QString & filename,