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(C++) 'Hello Wt' using Qt Creator under Raspian


Hello Wt application using Qt Creator under Raspian.



Technical facts


Application type(s)

Operating system(s) or programming environment(s)


Project type:

C++ standard:


Libraries used:






Qt project file: CppHelloWtQtCreatorRaspbian.pro


QT       += core
QT       -= gui
LIBS += -L/usr/lib -lwt -lwthttp -lboost_signals
CONFIG   += console
CONFIG   -= app_bundle
SOURCES += main.cpp








* Copyright (C) 2008 Emweb bvba, Heverlee, Belgium.
* See the LICENSE file for terms of use.

#include <Wt/WApplication>
#include <Wt/WBreak>
#include <Wt/WContainerWidget>
#include <Wt/WLineEdit>
#include <Wt/WPushButton>
#include <Wt/WText>

#include <boost/version.hpp>

using namespace Wt;

* A simple hello world application class which demonstrates how to react
* to events, read input, and give feed-back.
class HelloApplication : public WApplication
  HelloApplication(const WEnvironment& env);

  WLineEdit *nameEdit_;
  WText *greeting_;

  void greet();

* The env argument contains information about the new session, and
* the initial request. It must be passed to the WApplication
* constructor so it is typically also an argument for your custom
* application constructor.
HelloApplication::HelloApplication(const WEnvironment& env)
  : WApplication(env)
  setTitle("Hello world");                               // application title

  root()->addWidget(new WText("Your name, please ? "));  // show some text
  nameEdit_ = new WLineEdit(root());                     // allow text input
  nameEdit_->setFocus();                                 // give focus

  WPushButton *b = new WPushButton("Greet me.", root()); // create a button
  b->setMargin(5, Left);                                 // add 5 pixels margin

  root()->addWidget(new WBreak());                       // insert a line break

  greeting_ = new WText(root());                         // empty text

   * Connect signals with slots
   * - simple Wt-way
  b->clicked().connect(this, &HelloApplication::greet);

   * - using an arbitrary function object (binding values with boost::bind())
    (boost::bind(&HelloApplication::greet, this));

void HelloApplication::greet()
   * Update the text, using text input into the nameEdit_ field.
  greeting_->setText("Hello there, " + nameEdit_->text());

WApplication *createApplication(const WEnvironment& env)
   * You could read information from the environment to decide whether
   * the user has permission to start a new application
  return new HelloApplication(env);

int main(int argc, char **argv)
   * Your main method may set up some shared resources, but should then
   * start the server application (FastCGI or httpd) that starts listening
   * for requests, and handles all of the application life cycles.
   * The last argument to WRun specifies the function that will instantiate
   * new application objects. That function is executed when a new user surfs
   * to the Wt application, and after the library has negotiated browser
   * support. The function should return a newly instantiated application
   * object.
  return WRun(argc, argv, &createApplication);








rm Makefile
rm main.o
./CppHelloWtQtCreatorRaspbian --docroot . --http-address --http-port 8080






Deploying the Wt application locally


Call the start.sh script:



In the end you will see something like shown below. Your web server is running now.


[2010-Nov-19 16:41:38.365920] 6360 - [notice] "Wt: initializing built-in httpd"
[2010-Nov-19 16:41:38.366043] 6360 - [notice] "Reading Wt config file: /etc/wt/wt_config.xml (location = '/home/richel/qtsdk-2010.04/bin/Projects/Website/CppHelloWtQtCreatorUbuntu-build-desktop/CppHelloWtQtCreatorUbuntu')"
[2010-Nov-19 16:41:38.366592] 6360 - [notice] "Started server:"


Now, start your web browser and go to the following address:


You will see the 'Hello Wt' dynamic website. You just deployed your Wt application locally. This is just fine for debugging. If the application is ready to be put on the web, deploy the Wt application globally.






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