How to call DLL from another application in Qt - c++

Question

I am new in Qt development and developing Qt DLL which start TCP Server.When i am calling dll from my another app it will not receive any new connection socket.
So please guide me if i am doing any wrong step.
Server.h
extern "C" SERVERSHARED_EXPORT void CallServer();
class SERVERSHARED_EXPORT Server : public QObject
{
Q_OBJECT
public:
Server();
void CallServer();
void CallServer1();
QTcpServer *server;
QTcpSocket *socket ;
signals:
public slots:
void myConnection();
void closingClient();
};
Server.cpp
Server::Server()
{
}
void CallServer()
{
Server server_Obj;
server_Obj.CallServer1();
while (true)
::sleep(1000);
}
void Server::CallServer1()
{
server = new QTcpServer(this);
connect(server, SIGNAL(newConnection()),this, SLOT(myConnection()));
QHostAddress hostadd(ServerIP);
qDebug() << ServerIP;
qDebug() << Port;
if(!server->listen(hostadd,Port.toInt())) qDebug() << "\nWeb server could not start";
else qDebug() <<"\nWeb server is waiting for a connection";
}
void Server::myConnection()
{
qDebug() << "Detected Connection";
QByteArray Rdata;
socket = server->nextPendingConnection();
qDebug() << "Wait for connect = " << socket->waitForConnected();
while (socket->waitForReadyRead(10))
{
while(socket->bytesAvailable() > 0)
{
Rdata.append(socket->readAll());
}
}
qDebug() << "Final Testing is size = " << Rdata.size();
qDebug() << "Final Testing is" << Rdata;
}
.pro file
QT += core
QT += network
QT += widgets
QT -= gui
TARGET = Server
TEMPLATE = lib
DEFINES += SERVER_LIBRARY
SOURCES += server.cpp
HEADERS += server.h\
server_global.h
Another App:
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QLibrary library("Server.dll");
if (!library.load())
qDebug() << library.errorString();
if (library.load())
qDebug() << "library loaded";
typedef int(*pf)(void);
pf cwf = (pf)library.resolve("CallServer");
if (cwf) {
int x = cwf();
} else {
qDebug() << "Could not show widget from the loaded library";
}
qDebug() << "After call";
return a.exec();
}

Answer 1

Looks like it's not working because you are using QTcpSocket (your Server class) in asynchronous (signals/slots) way WITHOUT event loop - so it'll not work. You should add an event loop or use sockets in a blocking manner. For more details look at - http://doc.qt.io/qt-5/qtnetwork-blockingfortuneclient-example.html