is there any limitation of how fast or how many times signals can be emitted in Qt? -

i experimenting qthread other day , wanted create infinite loop using signals , not for, foreach or while code crash after emitting signal , executing slot number of times here's code:

//mainwindow.h #ifndef mainwindow_h #define mainwindow_h  #include <qmainwindow> #include "worker.h" #include <qthread> #include <qdebug>  namespace ui { class mainwindow; }  class mainwindow : public qmainwindow {     q_object  public:     explicit mainwindow(qwidget *parent = 0);     ~mainwindow();     void startthreads();  private:     ui::mainwindow *ui;     qthread thread;     worker *work;  };  #endif // mainwindow_h  //worker.h #ifndef worker_h #define worker_h  #include <qobject> #include <qdebug> #include <qmutex> #include "insiderobject.h"  class worker : public qobject {     q_object public:     explicit worker(qobject *parent = 0);  signals:     void doagain();     void okidid();     void finished();  public slots:     void printing(); };  #endif // worker_h  //mainwindow.cpp #include "mainwindow.h" #include "ui_mainwindow.h"  mainwindow::mainwindow(qwidget *parent) :     qmainwindow(parent),     ui(new ui::mainwindow) {     ui->setupui(this);     startthreads(); }  mainwindow::~mainwindow() {     thread.wait();     delete ui;     delete work; }  void mainwindow::startthreads() {     work = new worker;     work->movetothread(&thread);     connect(&thread, signal(started()), work, slot(printing()));     connect(work, signal(finished()), &thread, slot(quit()));     thread.start(); }  //worker.cpp #include "worker.h"  worker::worker(qobject *parent) :     qobject(parent) {     connect(this, signal(okidid()), this, slot(printing())); }  void worker::printing() {     qdebug() << "printing";     emit okidid(); }  //main.cpp  #include "mainwindow.h" #include <qapplication>  int main(int argc, char *argv[]) {     qapplication a(argc, argv);     mainwindow w;     w.show();      return a.exec(); } 

i have read entire documentation signal/slots , threads , queued connections or whatever hands on not understand reason crash... tried chatting people , developers @ qt irc chat room no 1 tell me reason.

what doing infinite recursion. emit okidid(); direct call worker::printing(). cause stack overflow.

you can fix using queued signal connection:

connect(this, signal(okidid()), this, slot(printing()), qt::queuedconnection); 

now emit okidid(); not direct function call anymore. worker::printing() function called in qt's event loop.