Μηνιαία αρχεία: Νοέμβριος 2017

Google Hash Code 2018 Nicosia Cyprus – Call for participation

 στο 2018 / Google / Hash Code  επισημασμένο με ετικέτα 2018 / code / Κύπρος / google / hash / hash code Από

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

 στο Applications  επισημασμένο με ετικέτα arduino / fedora / linux / root / x-server / xhost Από

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.

Manually set the CMake output folder 1

 στο Programming  επισημασμένο με ετικέτα add_executable / add_library / ARCHIVE_OUTPUT_DIRECTORY / cmake / CMAKE_ARCHIVE_OUTPUT_DIRECTORY / CMAKE_LIBRARY_OUTPUT_DIRECTORY / CMAKE_RUNTIME_OUTPUT_DIRECTORY / ENABLE_EXPORTS / LIBRARY_OUTPUT_DIRECTORY / MODULE / output directory / output folder / RUNTIME_OUTPUT_DIRECTORY / SHARED / static Από

If you want to manually set the global output folder for you whole CMake project and depending on the output you expect add the following configuration lines in the root CMakeLists.txt file of your project:

set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)

In case you wan to specify those folders per target, you can update them as follows:

set_target_properties( target_or_targets
  PROPERTIES
  ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib"
  LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib"
  RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin"
)

Please note that we are setting the same properties using different variables.

The CMAKE_ARCHIVE_OUTPUT_DIRECTORY variable is used to initialize the ARCHIVE_OUTPUT_DIRECTORY property on all the targets.
ARCHIVE_OUTPUT_DIRECTORY property specifies the directory into which archive target files should be built.
An archive output artifact of a buildsystem target may be:

  • The static library file (e.g. .lib or .a) of a static library target created by the add_library() command with the STATIC option.
  • On DLL platforms: the import library file (e.g. .lib) of a shared library target created by the add_library() command with the SHARED option.
  • On DLL platforms: the import library file (e.g. .lib) of an executable target created by the add_executable() command when its ENABLE_EXPORTS target property is set.

 

The CMAKE_LIBRARY_OUTPUT_DIRECTORY variable is used to initialize the LIBRARY_OUTPUT_DIRECTORY property on all the targets.
LIBRARY_OUTPUT_DIRECTORY property specifies the directory into which library target files should be built.
A library output artifact of a buildsystem target may be:
The loadable module file (e.g. .dll or .so) of a module library target created by the add_library() command with the MODULE option.
On non-DLL platforms: the shared library file (e.g. .so or .dylib) of a shared shared library target created by the add_library() command with the SHARED option.

 

The CMAKE_RUNTIME_OUTPUT_DIRECTORY variable is used to initialize the RUNTIME_OUTPUT_DIRECTORY property on all the targets.
RUNTIME_OUTPUT_DIRECTORY property specifies the directory into which runtime target files should be built.
A runtime output artifact of a buildsystem target may be:

  • The executable file (e.g. .exe) of an executable target created by the add_executable() command.
  • On DLL platforms: the executable file (e.g. .dll) of a shared library target created by the add_library() command with the SHARED option.

From: https://cmake.org/documentation/

Two ways to append a new argument to CMAKE_ARGS list for ExternalProject_Add

 στο Programming  επισημασμένο με ετικέτα cmake / CMAKE_ARGS / ExternalProject_Add / list / set Από

Recently, we wanted to pass a new cached value to an external project in CMake via the CMAKE_ARGS variable.

CMAKE_ARGS holds various types of arguments. From which, the arguments in the form -Dname:type=value are passed to the CMake command line and cannot be changed by the user.

We found two ways to add a new argument pair to the CMAKE_ARGS of the external project.

The first method uses the set function:

set(CMAKE_ARGS "${CMAKE_ARGS} -D${CACHE_VAR}${CACHE_VAR_TYPE}=\"${${CACHE_VAR}}\"")

where basically we create a new string that starts with the existing value of CMAKE_ARGS and then we append to its end the new pair.

The second method uses the list function:

list(APPEND CMAKE_ARGS "-D${CACHE_VAR}${CACHE_VAR_TYPE}=${${CACHE_VAR}}")

that treats CMAKE_ARGS as a list and it appends to its end the new pair.

To verify by hand that they were equivalent we did the following small test with success

#Copy the original value of ${CMAKE_ARGS}
set(CMAKE_ARGS_ORIGINAL ${CMAKE_ARGS})

#Define the Name, Type and Value for the new argument pairs
set(CACHE_VAR_P_NAME PRODUCTS_DIR)
set(CACHE_VAR_P_TYPE string)
set(CACHE_VAR_P_VALUE "someplace/with spaces")

set(CACHE_VAR_C_NAME CLIENTS_DIR)
set(CACHE_VAR_C_TYPE string)
set(CACHE_VAR_C_VALUE "another/place")

#Print the original value of ${CMAKE_ARGS}
MESSAGE(STATUS "CMAKE_ARGS: '" ${CMAKE_ARGS} "'")

#Append the two pairs to ${CMAKE_ARGS} using set
set(CMAKE_ARGS "${CMAKE_ARGS} -D${CACHE_VAR_P_NAME}:${CACHE_VAR_P_TYPE}=\"${CACHE_VAR_P_VALUE}\"")
set(CMAKE_ARGS "${CMAKE_ARGS} -D${CACHE_VAR_C_NAME}:${CACHE_VAR_C_TYPE}=\"${CACHE_VAR_C_VALUE}\"")

#Print the modified value of ${CMAKE_ARGS}
MESSAGE(STATUS "CMAKE_ARGS: '" ${CMAKE_ARGS} "'")

#Reset ${CMAKE_ARGS} to its original value
set(CMAKE_ARGS ${CMAKE_ARGS_ORIGINAL})

#Print the original value of ${CMAKE_ARGS} for verification
MESSAGE( STATUS "CMAKE_ARGS: '" ${CMAKE_ARGS} "'")

#Append the two pairs to ${CMAKE_ARGS} using list
list(APPEND CMAKE_ARGS "-D${CACHE_VAR_P_NAME}:${CACHE_VAR_P_TYPE}=\"${CACHE_VAR_P_VALUE}\"")
list(APPEND CMAKE_ARGS "-D${CACHE_VAR_C_NAME}:${CACHE_VAR_C_TYPE}=\"${CACHE_VAR_C_VALUE}\"")

#Print the modified value of ${CMAKE_ARGS}
#Notice that here we surrounded ${CMAKE_ARGS} with quotes so that it is printed as list of delimiter separated values
#Between each element the character ';' will be added because ${CMAKE_ARGS} is surrounded with quotes
MESSAGE(STATUS "CMAKE_ARGS: '" "${CMAKE_ARGS}" "'")

Which resulted in the following output

-- CMAKE_ARGS: ''
-- CMAKE_ARGS: ' -DPRODUCTS_DIR:string="someplace/with spaces" -DCLIENTS_DIR:string="another/place"'
-- CMAKE_ARGS: ''
-- CMAKE_ARGS: '-DPRODUCTS_DIR:string="someplace/with spaces";-DCLIENTS_DIR:string="another/place"'

From the output we can see that the two options treat the variable in a different way as using set just created a huge string containing both pairs while list created a list of two elements.
Both methods seem to work properly but we chose the list method for our external project.

The CMakeLists.txt file that we used to include the external project using custom CMAKE_ARGS resulted as follows:

cmake_minimum_required (VERSION 3.2.2)
include (ExternalProject)

set (TARGET c-banana-eat-banana)
project (${TARGET} C)

set (BANANA_ROOT ${CMAKE_CURRENT_BINARY_DIR} CACHE INTERNAL "")

#Add custom CMake arguments to be passed to the CMake command line of the external project
list(APPEND CMAKE_ARGS "-DARTIFACTS_DIR:string=\"${LIBRARIES_DIR}/${TARGET}\"")

ExternalProject_Add (${TARGET}
 URL ${CMAKE_CURRENT_SOURCE_DIR}/${TARGET}.zip
 URL URL_HASH MD5=34734a678729967f426931d913326112
 CMAKE_ARGS "${CMAKE_ARGS}"
 BUILD_IN_SOURCE 1)