QProcessManager Class Reference

Inheritance diagram for QProcessManager:

Public Functions
void	add (pid_t pid, QProcess *process)
void	catchDeadChildren ()
void	lock ()
	QProcessManager ()
void	remove (QProcess *process)
void	run ()
	The starting point for the thread. More...
void	unlock ()
	~QProcessManager ()
Public Functions inherited from QThread
void	exit (int retcode=0)
	Tells the thread's event loop to exit with a return code. More...
bool	isFinished () const
	Returns true if the thread is finished; otherwise returns false. More...
bool	isRunning () const
	Returns true if the thread is running; otherwise returns false. More...
Priority	priority () const
	Returns the priority for a running thread. More...
	QThread (QObject *parent=0)
	Constructs a new QThread to manage a new thread. More...
void	setPriority (Priority priority)
	This function sets the priority for a running thread. More...
void	setStackSize (uint stackSize)
	Sets the maximum stack size for the thread to stackSize. More...
uint	stackSize () const
	Returns the maximum stack size for the thread (if set with setStackSize()); otherwise returns zero. More...
bool	wait (unsigned long time=ULONG_MAX)
	Blocks the thread until either of these conditions is met: More...
	~QThread ()
	Destroys the QThread. More...
Public Functions inherited from QObject
bool	blockSignals (bool b)
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). More...
const QObjectList &	children () const
	Returns a list of child objects. More...
bool	connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
bool	disconnect (const char *signal=0, const QObject *receiver=0, const char *member=0)
bool	disconnect (const QObject *receiver, const char *member=0)
void	dumpObjectInfo ()
	Dumps information about signal connections, etc. More...
void	dumpObjectTree ()
	Dumps a tree of children to the debug output. More...
QList< QByteArray >	dynamicPropertyNames () const
	Returns the names of all properties that were dynamically added to the object using setProperty(). More...
virtual bool	event (QEvent *)
	This virtual function receives events to an object and should return true if the event e was recognized and processed. More...
virtual bool	eventFilter (QObject *, QEvent *)
	Filters events if this object has been installed as an event filter for the watched object. More...
template<typename T >
T	findChild (const QString &aName=QString()) const
	Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. More...
template<typename T >
QList< T >	findChildren (const QString &aName=QString()) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. More...
template<typename T >
QList< T >	findChildren (const QRegExp &re) const
bool	inherits (const char *classname) const
	Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false. More...
void	installEventFilter (QObject *)
	Installs an event filter filterObj on this object. More...
bool	isWidgetType () const
	Returns true if the object is a widget; otherwise returns false. More...
void	killTimer (int id)
	Kills the timer with timer identifier, id. More...
virtual const QMetaObject *	metaObject () const
	Returns a pointer to the meta-object of this object. More...
void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children. More...
QString	objectName () const
QObject *	parent () const
	Returns a pointer to the parent object. More...
QVariant	property (const char *name) const
	Returns the value of the object's name property. More...
Q_INVOKABLE	QObject (QObject *parent=0)
	Constructs an object with parent object parent. More...
void	removeEventFilter (QObject *)
	Removes an event filter object obj from this object. More...
void	setObjectName (const QString &name)
void	setParent (QObject *)
	Makes the object a child of parent. More...
bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value. More...
void	setUserData (uint id, QObjectUserData *data)
bool	signalsBlocked () const
	Returns true if signals are blocked; otherwise returns false. More...
int	startTimer (int interval)
	Starts a timer and returns a timer identifier, or returns zero if it could not start a timer. More...
QThread *	thread () const
	Returns the thread in which the object lives. More...
QObjectUserData *	userData (uint id) const
virtual	~QObject ()
	Destroys the object, deleting all its child objects. More...

Properties
QHash< int, QProcessInfo * >	children
QMutex	mutex

Additional Inherited Members
Public Types inherited from QThread
enum	Priority {   IdlePriority, LowestPriority, LowPriority, NormalPriority,   HighPriority, HighestPriority, TimeCriticalPriority, InheritPriority }
	This enum type indicates how the operating system should schedule newly created threads. More...
Public Slots inherited from QThread
void	quit ()
	Tells the thread's event loop to exit with return code 0 (success). More...
void	start (Priority=InheritPriority)
	Begins execution of the thread by calling run(). More...
void	terminate ()
	Terminates the execution of the thread. More...
Public Slots inherited from QObject
void	deleteLater ()
	Schedules this object for deletion. More...
Signals inherited from QThread
void	finished ()
	This signal is emitted when the thread has finished executing. More...
void	started ()
	This signal is emitted when the thread starts executing. More...
void	terminated ()
	This signal is emitted when the thread is terminated. More...
Signals inherited from QObject
void	destroyed (QObject *=0)
	This signal is emitted immediately before the object obj is destroyed, and can not be blocked. More...
Static Public Functions inherited from QThread
static QThread *	currentThread ()
	Returns a pointer to a QThread which manages the currently executing thread. More...
static Qt::HANDLE	currentThreadId ()
	Returns the thread handle of the currently executing thread. More...
static int	idealThreadCount ()
	Returns the ideal number of threads that can be run on the system. More...
static void	yieldCurrentThread ()
	Yields execution of the current thread to another runnable thread, if any. More...
Static Public Functions inherited from QObject
static bool	connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
	Creates a connection of the given type from the signal in the sender object to the method in the receiver object. More...
static bool	connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
static bool	disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
	Disconnects signal in object sender from method in object receiver. More...
static bool	disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
static uint	registerUserData ()
static QString	tr (const char *sourceText, const char *comment=0, int n=-1)
static QString	trUtf8 (const char *sourceText, const char *comment=0, int n=-1)
Static Public Variables inherited from QObject
static const QMetaObject	staticMetaObject
	This variable stores the meta-object for the class. More...
Protected Functions inherited from QThread
int	exec ()
	Enters the event loop and waits until exit() is called, returning the value that was passed to exit(). More...
	QThread (QThreadPrivate &dd, QObject *parent=0)
Protected Functions inherited from QObject
virtual void	childEvent (QChildEvent *)
	This event handler can be reimplemented in a subclass to receive child events. More...
virtual void	connectNotify (const char *signal)
	This virtual function is called when something has been connected to signal in this object. More...
virtual void	customEvent (QEvent *)
	This event handler can be reimplemented in a subclass to receive custom events. More...
virtual void	disconnectNotify (const char *signal)
	This virtual function is called when something has been disconnected from signal in this object. More...
	QObject (QObjectPrivate &dd, QObject *parent=0)
int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal. More...
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns 0. More...
int	senderSignalIndex () const
virtual void	timerEvent (QTimerEvent *)
	This event handler can be reimplemented in a subclass to receive timer events for the object. More...
Static Protected Functions inherited from QThread
static void	msleep (unsigned long)
	Forces the current thread to sleep for msecs milliseconds. More...
static void	setTerminationEnabled (bool enabled=true)
	Enables or disables termination of the current thread based on the enabled parameter. More...
static void	sleep (unsigned long)
	Forces the current thread to sleep for secs seconds. More...
static void	usleep (unsigned long)
	Forces the current thread to sleep for usecs microseconds. More...
Protected Variables inherited from QObject
QScopedPointer< QObjectData >	d_ptr
Static Protected Variables inherited from QObject
static const QMetaObject	staticQtMetaObject
Related Functions inherited from QObject
T	qFindChildqFindChildren (const QObject *obj, const QString &name)()
QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()
QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QRegExp &regExp)()
T *	qobject_cast (QObject *object)
	QObjectList
void *	qt_find_obj_child (QObject *parent, const char *type, const QString &name)
	Returns a pointer to the object named name that inherits type and with a given parent. More...

Detailed Description

Definition at line 176 of file qprocess_unix.cpp.

Constructors and Destructors

QProcessManager()

QProcessManager::QProcessManager

(

)

Definition at line 207 of file qprocess_unix.cpp.

{
#if defined (QPROCESS_DEBUG)
    qDebug() << "QProcessManager::QProcessManager()";
#endif
    // initialize the dead child pipe and make it non-blocking. in the
    // extremely unlikely event that the pipe fills up, we do not under any
    // circumstances want to block.
    qt_safe_pipe(qt_qprocess_deadChild_pipe, O_NONBLOCK);

    // set up the SIGCHLD handler, which writes a single byte to the dead
    // child pipe every time a child dies.

    struct sigaction action;
    // use the old handler as template, i.e., preserve the signal mask
    // otherwise the original signal handler might be interrupted although it
    // was marked to never be interrupted
    ::sigaction(SIGCHLD, NULL, &action);
    action.sa_sigaction = qt_sa_sigchld_sigaction;
    // set the SA_SIGINFO flag such that we can use the three argument handler
    // function
    action.sa_flags = SA_NOCLDSTOP | SA_SIGINFO;
    ::sigaction(SIGCHLD, &action, &qt_sa_old_sigchld_handler);
}

~QProcessManager()

QProcessManager::~QProcessManager

(

)

Definition at line 232 of file qprocess_unix.cpp.

{
    // notify the thread that we're shutting down.
    qt_safe_write(qt_qprocess_deadChild_pipe[1], "@", 1);
    qt_safe_close(qt_qprocess_deadChild_pipe[1]);
    wait();

    // on certain unixes, closing the reading end of the pipe will cause
    // select in run() to block forever, rather than return with EBADF.
    qt_safe_close(qt_qprocess_deadChild_pipe[0]);

    qt_qprocess_deadChild_pipe[0] = -1;
    qt_qprocess_deadChild_pipe[1] = -1;

    qDeleteAll(children.values());
    children.clear();

    struct sigaction currentAction;
    ::sigaction(SIGCHLD, 0, &currentAction);
    if (currentAction.sa_sigaction == qt_sa_sigchld_sigaction) {
        ::sigaction(SIGCHLD, &qt_sa_old_sigchld_handler, 0);
    }
}

Functions

add()

void QProcessManager::add	(	pid_t	pid,
		QProcess *	process
	)

Definition at line 311 of file qprocess_unix.cpp.

Referenced by QProcessPrivate::startProcess().

{
#if defined (QPROCESS_DEBUG)
    qDebug() << "QProcessManager::add() adding pid" << pid << "process" << process;
#endif

    // insert a new info structure for this process
    QProcessInfo *info = new QProcessInfo;
    info->process = process;
    info->deathPipe = process->d_func()->deathPipe[1];
    info->exitResult = 0;
    info->pid = pid;

    int serial = idCounter.fetchAndAddRelaxed(1);
    process->d_func()->serial = serial;
    children.insert(serial, info);
}

catchDeadChildren()

void QProcessManager::catchDeadChildren

(

)

Definition at line 289 of file qprocess_unix.cpp.

{
    QMutexLocker locker(&mutex);

    // try to catch all children whose pid we have registered, and whose
    // deathPipe is still valid (i.e, we have not already notified it).
    QHash<int, QProcessInfo *>::Iterator it = children.begin();
    while (it != children.end()) {
        // notify all children that they may have died. they need to run
        // waitpid() in their own thread.
        QProcessInfo *info = it.value();
        qt_safe_write(info->deathPipe, "", 1);

#if defined (QPROCESS_DEBUG)
        qDebug() << "QProcessManager::run() sending death notice to" << info->process;
#endif
        ++it;
    }
}

lock()

void QProcessManager::lock

(

)

Definition at line 342 of file qprocess_unix.cpp.

Referenced by QProcessPrivate::startProcess().

{
    mutex.lock();
}

remove()

void QProcessManager::remove

(

QProcess *

process

)

Definition at line 329 of file qprocess_unix.cpp.

Referenced by QProcessPrivate::findExitCode(), and QProcessPrivate::waitForDeadChild().

{
    QMutexLocker locker(&mutex);

    int serial = process->d_func()->serial;
    QProcessInfo *info = children.take(serial);
#if defined (QPROCESS_DEBUG)
    if (info)
        qDebug() << "QProcessManager::remove() removing pid" << info->pid << "process" << info->process;
#endif
    delete info;
}

run()

void QProcessManager::run ( void  )

virtual

The starting point for the thread.

After calling start(), the newly created thread calls this function. The default implementation simply calls exec().

You can reimplement this function to facilitate advanced thread management. Returning from this method will end the execution of the thread.

See also

start() wait()

Reimplemented from QThread.

Definition at line 256 of file qprocess_unix.cpp.

{
    forever {
        fd_set readset;
        FD_ZERO(&readset);
        FD_SET(qt_qprocess_deadChild_pipe[0], &readset);

#if defined (QPROCESS_DEBUG)
        qDebug() << "QProcessManager::run() waiting for children to die";
#endif

        // block forever, or until activity is detected on the dead child
        // pipe. the only other peers are the SIGCHLD signal handler, and the
        // QProcessManager destructor.
        int nselect = select(qt_qprocess_deadChild_pipe[0] + 1, &readset, 0, 0, 0);
        if (nselect < 0) {
            if (errno == EINTR)
                continue;
            break;
        }

        // empty only one byte from the pipe, even though several SIGCHLD
        // signals may have been delivered in the meantime, to avoid race
        // conditions.
        char c;
        if (qt_safe_read(qt_qprocess_deadChild_pipe[0], &c, 1) < 0 || c == '@')
            break;

        // catch any and all children that we can.
        catchDeadChildren();
    }
}

unlock()

void QProcessManager::unlock

(

)

Definition at line 347 of file qprocess_unix.cpp.

Referenced by QProcessPrivate::startProcess().

{
    mutex.unlock();
}

Properties

children

QHash<int, QProcessInfo *> QProcessManager::children

private

Definition at line 192 of file qprocess_unix.cpp.

mutex

QMutex QProcessManager::mutex

private

Definition at line 191 of file qprocess_unix.cpp.

---

The documentation for this class was generated from the following file:

• /src/corelib/io/qprocess_unix.cpp