Month: December 2015

Repair, Restore, or Reinstall Grub 2 with a Ubuntu Live CD or USB

sudo mount /dev/sda1 /mnt
sudo mount --bind /dev /mnt/dev &&
sudo mount --bind /dev/pts /mnt/dev/pts &&
sudo mount --bind /proc /mnt/proc &&
sudo mount --bind /sys /mnt/sys
sudo chroot /mnt
grub-install /dev/sda

or

grub-install --recheck /dev/sda
update-grub
exit &&
sudo umount /mnt/sys &&
sudo umount /mnt/proc &&
sudo umount /mnt/dev/pts &&
sudo umount /mnt/dev &&
sudo umount /mnt

References :
http://howtoubuntu.org/how-to-repair-restore-reinstall-grub-2-with-a-ubuntu-live-cd

Install Android SDK on Ubuntu

sudo apt-get install libc6:i386 libncurses5:i386 libstdc++6:i386 lib32z1 libbz2-1.0:i386
sudo gedit /etc/profile

add :

#AndroidDev PATH
export PATH=${PATH}:/opt/android-sdk-linux/tools
export PATH=${PATH}:/opt/android-sdk-linux/platform-tools

at the end run the following command to refresh profile or restart your system

. /etc/profile

Or
add this to ~/.bashrc :

export ANDROID_HOME=/<installation location>/android-sdk-linux
export PATH=${PATH}:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools

References
https://help.ubuntu.com/community/AndroidSDK
https://developer.android.com/studio/install.html

Configure Xdebug for debugging PHP on Ubuntu

sudo apt-get install php5-xdebug
find / -name 'xdebug.so'

Now update the options in PHP.INI – /etc/php5/apache2/php.ini

# Added for xdebug
zend_extension="/usr/lib/php5/20121212/xdebug.so"
xdebug.remote_enable=1
xdebug.remote_handler=dbgp
xdebug.remote_mode=req
xdebug.remote_host=127.0.0.1
xdebug.remote_port=9000
xdebug.max_nesting_level=300

Restart Apache2, and you are ready to go!

sudo service apache2 restart

References :
http://ubuntuforums.org/showthread.php?t=525257
http://wylbur.us/2014-06-17-add-xdebug-to-ubuntu-1404
http://purencool.com/installing-xdebug-on-ubuntu
https://www.jetbrains.com/phpstorm/help/configuring-xdebug.html

Configure CMake to use GTK

First install libgtk-3-dev and libgtkmm-3.0-dev then :

cmake_minimum_required(VERSION 3.7)
project(project1)

include(FindPkgConfig)
pkg_check_modules(GTK REQUIRED "gtk+-3.0")

include_directories(${GTK_INCLUDE_DIRS})
link_directories(${GTK3_LIBRARY_DIRS})
add_definitions(${GTK3_CFLAGS_OTHER})

set(CMAKE_CXX_STANDARD 11)
set(SOURCE_FILES main.cpp)
add_executable(untitled ${SOURCE_FILES})
target_link_libraries(${CMAKE_PROJECT_NAME} ${GTK3_LIBRARIES})

References :

http://stackoverflow.com/questions/27514291/how-to-add-compiler-arguments-using-cmake

GCC -fpic option

-fpic

Generate position-independent code (PIC) suitable for use in a shared library, if supported for the target machine. Such code accesses all constant addresses through a global offset table (GOT). The dynamic loader resolves the GOT entries when the program starts (the dynamic loader is not part of GCC; it is part of the operating system). If the GOT size for the linked executable exceeds a machine-specific maximum size, you get an error message from the linker indicating that -fpic does not work; in that case, recompile with -fPIC instead. (These maximums are 8k on the SPARC, 28k on AArch64 and 32k on the m68k and RS/6000. The x86 has no such limit.)

Position-independent code requires special support, and therefore works only on certain machines. For the x86, GCC supports PIC for System V but not for the Sun 386i. Code generated for the IBM RS/6000 is always position-independent.

When this flag is set, the macros __pic__ and __PIC__ are defined to 1.

from Wikipedia :

In computing, position-independent code (PIC) or position-independent executable (PIE) is a body of machine code that, being placed somewhere in the primary memory, executes properly regardless of its absolute address. PIC is commonly used for shared libraries, so that the same library code can be loaded in a location in each program address space where it will not overlap any other uses of memory (for example, other shared libraries)

Example :

swig -python hello.i
gcc -fpic -c hellomodule.c hello_wrap.c -I/usr/include/python3.4/
gcc -shared hellomodule.o hello_wrap.o -o _hello.so

References :

https://gcc.gnu.org/onlinedocs/gcc/Option-Summary.html https://en.wikipedia.org/wiki/Position-independent_code

GCC -shared option

-shared
Produce a shared object which can then be linked with other objects to form an executable. Not all systems support this option. For predictable results, you must also specify the same set of options used for compilation (-fpic, -fPIC, or model suboptions) when you specify this linker option.

Example :

gcc -fpic -c hellomodule.c hello_wrap.c -I/usr/include/python3.4/
gcc -shared hellomodule.o hello_wrap.o -o _hello.so

Reference :

https://gcc.gnu.org/onlinedocs/gcc/Option-Summary.html