c++ - Starting processes in threads as spawned -

i have problem looking create processing class, , want feed data it, put thread, , tell start working. currently, have that:

processingclass *worker = new processingclass(mydata); connect(this, signal(startworking()), worker, slot(startworking())); connect(worker, signal(doneworking(data)), this, slot(workerfinished(data))); qthread *workerthread = new qthread; worker->movetothread(workerthread); workerthread->start();  emit(startworking()); 

what ends doing creates worker, gives data want process, connects needs connected work, moves on over thread, , emits signal start working. more or less want to, there issue. namely, want putting loop:

while (reason){     ...//gathering data give worker     processingclass *worker = new processingclass(mydata);     connect(this, signal(startworking()), worker, slot(startworking()));     connect(worker, signal(doneworking(data)), this, slot(workerfinished(data)));     qthread *workerthread = new qthread;     worker->movetothread(workerthread);     workerthread->start(); } emit(startworking()); 

this accomplish want do, sticking in memory, waiting until there, , set off every single thread simultaneously compete resources until done. considering current data amount on 1000 different threads, each of takes (from previous iterations of program) ~1-2 minutes process information, , last version crashed because ran out of memory (i think...) don't particularly method anymore.

what figure out way move resources want thread, , set off thread work immediately. want able pause loop after amount of threads running (so not overload computer again) , continue loop , set off next thread after 1 of previous threads done.

is there nicer way accomplish this?

you should have fixed number of worker threads, , iterate loop when there threads not busy.

if insist on using qobject, can create qrunnable wrapper run worker objects until completion in thread pool, , track progress issue more work:

class processingrunnable : public processingclass, public qrunnable {   void run() q_decl_override {     qeventloop loop;     movetothread(qthread::currentthread());     qmetaobject::invokemethod(this, "startworking", qt::queuedconnection);     loop.exec();     movetothread(0);   } public:   explicit processingrunnable(const data & data) :      processingclass(data) {     setautodelete(false);     movetothread(0); // moved worker thread later   } };  class jobmanager : public qobject {   q_object   qthreadpool m_pool;   qscopedpointer<processingrunnable> m_worker;   int m_jobs; public:   q_signal void alljobsfinished();   q_slot void runjobs() {     while (true) {       if (m_worker) {         if (m_pool.trystart(m_worker.data())           m_worker.take();         else           break;         }       }       if (! reason) break;       ... // gather data give worker       m_worker.reset(new processingrunnable(mydata));       ++ m_jobs;       connect(m_worker, &processingrunnable::doneworking, [this]{         -- m_jobs;         runjobs();         if (! m_jobs) emit alljobsfinished();       });     }   }   explicit jobmanager(qobject * parent = 0) : qobject(parent),     m_jobs(0) {   } }  int main(int argc, char ** argv) {   qcoreapplication app(argc, argv);   ...   jobmanager manager;   qobject::connect(&manager, &jobmanger::alljobsfinished,                    &app, &qcoreapplication::quit, qt::queuedconnection);   manager.runjobs();   ...   return app.exec(); } 

for kind of application, might simpler make processingclass simple functor, not qobject, , use qtconcurrent::run , qfuturewatcher.