How to remotely debug Qt applications

Introduction

This is a guide to write a Qt program on one virtual PC, and deploy and debug it on another virtual PC. As a first step, both virtual PC's are running linux. this guide assumes a windows 7 host system, but this should work on each platform that can run Virtualbox.

Master

This PC will be running the Qt IDE. This is where you will write the Qt program.

Target

This PC will be the target. This is where the Qt program will run. This PC has almost nothing installed, no IDE, no compilers, just a runtime

Setting up the virtual machines

download needed files

Download Virtual box and VirtualBox Extension Pack from this site: http://dlc-cdn.sun.com/virtualbox/4.3.28/index.html This tutorial has been tested with virtualbox 4.3.28. Next download Ubuntu from this site: http://www.ubuntu.com/download/desktop This tutorial has been tested with 15.04 32bit.

Install Virtualbox

In windows, open VirtualBox-4.3.28-100309-Win.exe, and accept the defaults. Also accept the 4 prompts about device software installation. Then install Oracle_VM_VirtualBox_Extension_Pack-4.3.28-100309.vbox-extpack by double-clicking the file. Then click install, scroll down the PUEL, and click 'I agree'

Create the virtual machines, with a virtual network between them

Start Virtualbox, click file-preferences-general. Set the default Machine Folder to a spacious location. Next click machine-new, set the name to Ubuntu-master, type linux, version Ubuntu (32 bit), next Set memory size to 1024MB, next, create a virtual hard drive now, create, VDI, next, Dynamically allocated, next, select size: 50BG. Select Ubuntu master, then click Settings-storage-CD icon-choose a virtual CD/DVD file... Then browse to ubuntu-15.04-desktop-i386.iso, and click open. Select Network, Adapter2, enable adapter, attached to internal network, name "virtualLAN". click OK. Select Ubuntu-master, click machine-clone. New machine name: Ubuntu-target, next clone type=Full clone, clone

Install Ubuntu on both virtual machines

Start Virtualbox, Select 'ubuntu-master', click run. In a new window 'Ubuntu-master [running]', ubuntu should boot from CD. On my PC, the installer does not react to the mouseclicks, so use the tab, space and return keys to make the selections. Choose "Install Ubuntu". Select "Download updates while installing" and select "Install this third-party software". Choose "Erase disk and install ubuntu", and "Install Now", and "Continue". Next select your location, and choose "Continue". Next choose a keyboard layout and "Continue". Next choose a name and password. Choose "Master" as the computer name, and select "log in automatically", and choose "Continue", after some time, choose "Restart Now". After some time the desktop is loaded.

Internet connection

Open a terminal (click top-left, search terminal). Check your internet connection with the following command:

$ ping www.google.com

...64 bytes from ... time ..ms

$ route

Destination Gateway ... default 10.0.2.2

Next click on the top-left networking icon, and choose "Connection information". Wired connection 1 is active, and has the default route 10.0.2.2

VirtualLAN connection

Click on the top-left networking icon, and choose "Edit connections" Select Wired connection 2, and choose edit. Select IPv4 Settings, and enter the following information: Method: Manual Addresses: 192.168.107.1 Netmask: 255.255.255.0 Gateway: 0.0.0.0 DNS servers: <empty> search domains: <empty> Next press "save" Click on the top-left networking icon, and choose "Wired connection 2 disconnect", and then "Wirend connection 2". Now the new settings for wired connection 2 are active.

Clone the master virual machine to create the target

Shut down the master virtual PC. Next goto Virtual Box, and select ubuntu-master. Now choose Machine-clone, and set the name to ubuntu-target. Also enable "Reinitialize the MAC address of all network cards", and choose next. Choose "Linked clone", and clone http://www.sysprobs.com/linked-clone-virtualbox-how-to-clone-virtual-machine

Setting up the target machine

Start Virtualbox, Select 'ubuntu-target', click run. After some time the desktop is loaded. Click system settings-Details. Change the device name from "Master" to "Target". Next logout and login, to let the new machine name take effect. Click on the top-left networking icon, and choose "Edit connections" Select Wired connection 2, and choose edit. Select IPv4 Settings, and enter the following information: Method: Manual Addresses: 192.168.107.2 Netmask: 255.255.255.0 Gateway: 0.0.0.0 DNS servers: <empty> search domains: <empty> Next press "save" Click on the top-left networking icon, and choose "Wired connection 2 disconnect", and then "Wirend connection 2". Now the new settings for wired connection 2 are active.

Testing the Virtual Lan connection

Start both the ubuntu-master and the ubuntu-target machine. On the master, enter the following command to ping the target: $ ping 192.168.107.2 On the slave, enter the following command to ping the master: $ping 192.168.107.1

Install Qt on the master PC

Start ubuntu software center. Search for qt-sdk, select it, and press install. next type in your password. After some time Qtcreator is installed.

remote debug the application

Start both the master and the target virtual machine.

Create a new project on the master

On the master start Qt Creator. Select new project-applications-QT Widgets Application-choose. Pick a name and a location, and click next. select the kit "Desktop", and click next. Choose the names for the classed etc, and press next. Choose <None> for version control, and press finish.

Connect to the target

In Qt Creator, Click on projects at the left side. Then click Manage Kits... This will open the options screen. Then select devices, and click Add... Generic Linux Device, start wizzard. Enter the following settings: Name: ubuntu-target IP: 192.168.107.2 User: <your username> authentication type: password password: <your password> choose next and finish. Now the error "SSH connection failure: Connection refused" comes up. Click close

on ubuntu-target, start ubuntu software center. Search for openssh-server, and install it.

on ubuntu-master, select ubuntu-target, and click test. Now the device test succeeds. Click close and OK.

Deploy to the target

In Qt Creator on ubuntu-master, click projects, Manage Kits... This will open the options screen. Now click Build & Run, Kits, Add. Enter the following settings:

name: ubuntu-target
Device type: generic linux device
Device: ubuntu-target
Sysroot: <empty>
Compiler GCC (x86 32 bit in /usr/bin)
Debugger: System GDB
Qt version: Your Qt version

Click OK

In projects-untiteld-Build & Run click add Kit-ubuntu-target.

Now open the .pro file and add the lines

target.path = /path/where/to/deploy
INSTALLS += target

The /path/where/to/deploy is the directory in which the executable will be deployed, so be sure that it exists and the user you chose has writing permissions to it.

In Qt creator click the little arrow next to debug, and select ubuntu-target debug. Now click the green arrow with the bug on top (Start Debugging).

You should see, in the "Application output" window, the message

error while loading shared libraries: libQt5Core.so.5: cannot open shared object file: No such file or directory

This means that the libraries were not found. So let's copy them.

Go into the folder on the master PC with the libraries. For instance if you chose to install gcc 64-bit for Qt 5.7, this folder will be QT_INSTALL_DIR/5.7/gcc_64. Copy the required libraries; for a barebone Qt console application you will need libicudata.so*, libicui18n.so*, libicuuc.so* and libQt5Core.so*; if you use other plugins (e.g. Qt GUI) you will need other libraries. It is suggested to compress them into a .tar.gz file, so symlinks and file properties will be preserved.

Now go on the slave PC and copy them either into either /usr/lib or QT_INSTALL_DIR/5.7/gcc_64. If you choose the latter, remember to use exactly the same path as the original one.

Once copied, try to launch the debug again. The program should start on the remote device (and you will see its output in the "Application Output" window)