Yearly Archives: 2017

Enable C++11 standard for GCC on Eclipse CDT

 in Applications  tagged -std=c++11 / C++ / C++11 / CDT / compiler / eclipse / eclipse CDT / gcc / GCC C++ Compiler / standard by

When using Eclipse CDT to write C++, we noticed that it did not enable by default the C++11 standard. Following the steps below, we added the -std=c++11 flag on the GCC C++ Compiler command line arguments enabling the standard for our use.

  1. From the main window of Eclipse, on the list on the left, where your projects are listed, right click on your project and then click Properties from the new menu
  2. In the new window, navigate from the list on the left and expand the C/C++ Build option to view its children and then click the Settings item
  3. In the middle of the window, you will see a new list, expand (if needed) the item GCC C++ Compiler and click on the Miscellaneous child
  4. On the right, a text box named Other Flags will appear, append -std=c++11 to the list of tokens in the box as seen in the image below
  5. Click on the Apply button for the effects to take place and then the OK button to close the properties window

Next time you compile, the -std=c++11 flag will be present on your compiler command line and the C++11 standard will be used.

Google Hash Code 2018 Nicosia Cyprus – Call for participation

 in 2018 / Google / Hash Code  tagged 2018 / code / cyprus / google / hash / hash code by

We’ll be hosting a hub at the University of Cyprus for the Online Qualification Round of Hash Code, a team-based programming competition created by Google for university students and industry professionals. The Online Qualification Round takes place on the 1st of March at 19:30 EET and registered teams from Cyprus are invited to participate from our hub, which will take place at the Computer Science Department. Top scoring teams from the Online Qualification Round will then be invited to Google’s Paris office to compete in the Final Round of the competition in April.

If you’re interested in joining our hub, find a team (two to four people) and register at g.co/hashcode. Make sure to select University of Cyprus from the list of hubs in the Judge System.

For more information about this and other hubs in Cyprus (including the twin event in Limassol) visit https://goo.gl/uuRspx

Hash Code 2018 Nicosia Cyprus – Facebook Event

Thanks!

Address:

Rooms: 101, 102, 103
Department of Computer Science,
Pure and Applied Sciences (FST-01)
University of Cyprus
1 University Avenue
2109 Aglantzia, CYPRUS

Date and Time:

1st March 2018
From: 19:30 EET
To: 23:30 EET

Free Amenities Offered

High speed Internet access
Wi-Fi access to the Internet for your mobile devices (personal computers and smart phones)
Lab computers will be available for use by the participants
Food in the form of snacks and beverages will be available outside the labs

Google Hash Code 2018 – Online Qualification Round Schedule

18:30 EET:

  • The hub will open to the public
  • People can view the live stream on the video projector
  • Teams can set themselves up with the help of the volunteers

19:30 EET:

  • Live stream starts

19:45 EET:

  • Task will be made available, competition starts
  • Scoreboard will be displayed on the video projector
  • Participating teams will be confirmed in the Judge System

23:30 EET:

  • End of the competition
  • Announcement of the score for the local teams

00:00 EET:

  • The hub will close

Start Arduino IDE as root on Fedora / Allow root to start an X application

 in Applications  tagged arduino / fedora / linux / root / x-server / xhost by

Solution

Execute the following as a normal user


xhost +si:localuser:root;
sudo ./arduino;

Background Story and More Information

Recently we needed to start the official Arduino IDE as root on Fedora to allow the application to take control of the serial port.
We were getting the following error whenever we tried to upload the application to the board:

processing.app.debug.RunnerException
 at cc.arduino.packages.uploaders.SerialUploader.uploadUsingPreferences(SerialUploader.java:160)
 at cc.arduino.UploaderUtils.upload(UploaderUtils.java:78)
 at processing.app.SketchController.upload(SketchController.java:713)
 at processing.app.SketchController.exportApplet(SketchController.java:686)
 at processing.app.Editor$DefaultExportHandler.run(Editor.java:2168)
 at java.lang.Thread.run(Thread.java:748)
Caused by: processing.app.SerialException: Error touching serial port '/dev/ttyACM0'.
 at processing.app.Serial.touchForCDCReset(Serial.java:107)
 at cc.arduino.packages.uploaders.SerialUploader.uploadUsingPreferences(SerialUploader.java:144)
 ... 5 more
Caused by: jssc.SerialPortException: Port name - /dev/ttyACM0; Method name - openPort(); Exception type - Permission denied.
 at jssc.SerialPort.openPort(SerialPort.java:170)
 at processing.app.Serial.touchForCDCReset(Serial.java:101)
 ... 6 more

So, we tried to start the arduino IDE using root and got another error:

[george@bytefreaks bin]$ sudo ./arduino;
[sudo] password for george: 
No protocol specified
Picked up JAVA_TOOL_OPTIONS: 
No protocol specified
java.awt.AWTError: Can't connect to X11 window server using ':0' as the value of the DISPLAY variable.
	at sun.awt.X11GraphicsEnvironment.initDisplay(Native Method)
	at sun.awt.X11GraphicsEnvironment.access$200(X11GraphicsEnvironment.java:65)
	at sun.awt.X11GraphicsEnvironment$1.run(X11GraphicsEnvironment.java:115)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.awt.X11GraphicsEnvironment.(X11GraphicsEnvironment.java:74)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:264)
	at java.awt.GraphicsEnvironment.createGE(GraphicsEnvironment.java:103)
	at java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(GraphicsEnvironment.java:82)
	at sun.awt.X11.XToolkit.(XToolkit.java:126)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:264)
	at java.awt.Toolkit$2.run(Toolkit.java:860)
	at java.awt.Toolkit$2.run(Toolkit.java:855)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.awt.Toolkit.getDefaultToolkit(Toolkit.java:854)
	at java.awt.SystemColor.updateSystemColors(SystemColor.java:473)
	at java.awt.SystemColor.(SystemColor.java:465)
	at processing.app.Theme.init(Theme.java:84)
	at processing.app.Base.(Base.java:219)
	at processing.app.Base.main(Base.java:144)

This error occurred because the default configuration of the X server permissions did not allow the root to connect to it.
To verify this, we used xhost (the X server access control program) to check the permissions.
Executing xhost with no command line arguments gave us a message indicating whether or not access control was currently enabled, followed by the list of those users allowed to connect.
For example in our case the output was as follows:


[george@bytefreaks bin]$ xhost
access control enabled, only authorized clients can connect
SI:localuser:george

To add root to the list of users that was allowed to start an X application we executed the following command:


[george@bytefreaks bin]$ xhost +si:localuser:root
localuser:root being added to access control list

Executing xhost again, we got the updated list which included the root


[george@bytefreaks bin]$ xhost
access control enabled, only authorized clients can connect
SI:localuser:root
SI:localuser:george

After this, we were able to start arduino IDE using sudo with no problems.


[george@bytefreaks bin]$ sudo ./arduino;

Note: This patch is not permanent, we actually execute it once at every restart of the machine.