구차니의 잡동사니 모음

$ cat /proc/cpuinfo

processor       : 0

model name      : ARMv7 Processor rev 4 (v7l)

Speed           : 1.4GHz

Features        : swp half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt

CPU implementer : 0x41

CPU architecture: 7

CPU variant     : 0x2

CPU part        : 0xc0f

CPU revision    : 4

processor       : 1

model name      : ARMv7 Processor rev 4 (v7l)

Speed           : 1.4GHz

Features        : swp half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt

CPU implementer : 0x41

CPU architecture: 7

CPU variant     : 0x2

CPU part        : 0xc0f

CPU revision    : 4

Hardware        : AnnapurnaLabs Alpine (Device Tree)

Revision        : 0000

Serial          : 0000000000000000 

$ sudo apt-get install redmine

Reading package lists... Done

Building dependency tree

Reading state information... Done

The following extra packages will be installed:

  bundler dbconfig-common fonts-droid ghostscript imagemagick-common libev4 libfcgi-ruby1.9.1

  libfcgi0ldbl libgmp-dev libgmpxx4ldbl libgs9 libgs9-common libijs-0.35 libjbig2dec0

  libjs-coffeescript libjs-jquery-ui libjs-prototype libjs-scriptaculous libjsoncpp0 liblqr-1-0

  libmagickcore-6.q16-2 rake redmine-sqlite ruby-actionmailer ruby-actionpack

  ruby-actionpack-action-caching ruby-actionview ruby-activemodel ruby-activerecord

  ruby-activesupport ruby-arel ruby-atomic ruby-awesome-nested-set ruby-blankslate ruby-builder

  ruby-celluloid ruby-coderay ruby-coffee-rails ruby-coffee-script ruby-coffee-script-source

  ruby-dev ruby-erubis ruby-execjs ruby-fcgi ruby-ffi ruby-hike ruby-hmac ruby-i18n

  ruby-jbuilder ruby-jquery-rails ruby-json ruby-listen ruby-mail ruby-mime-types ruby-minitest

  ruby-multi-json ruby-net-http-persistent ruby-net-ldap ruby-oj ruby-openid ruby-passenger

  ruby-polyglot ruby-protected-attributes ruby-rack ruby-rack-openid ruby-rack-test ruby-rails

  ruby-rails-observers ruby-railties ruby-rb-inotify ruby-redcarpet ruby-request-store

  ruby-rmagick ruby-sass ruby-sass-rails ruby-sdoc ruby-spring ruby-sprockets

  ruby-sprockets-rails ruby-sqlite3 ruby-thor ruby-thread-safe ruby-tilt ruby-timers

  ruby-treetop ruby-turbolinks ruby-tzinfo ruby-uglifier ruby-yajl ruby2.1-dev sqlite3 zip

Suggested packages:

  virtual-mysql-client mysql-client postgresql-client ghostscript-x libgmp10-doc libmpfr-dev

  coffeescript libjs-jquery-ui-docs libmagickcore-6.q16-2-extra bzr cvs darcs mercurial

  subversion ruby-builder-doc rails ruby-passenger-doc ruby-compass treetop doc-base sqlite3-doc

The following NEW packages will be installed:

  bundler dbconfig-common fonts-droid ghostscript imagemagick-common libev4 libfcgi-ruby1.9.1

  libfcgi0ldbl libgmp-dev libgmpxx4ldbl libgs9 libgs9-common libijs-0.35 libjbig2dec0

  libjs-coffeescript libjs-jquery-ui libjs-prototype libjs-scriptaculous libjsoncpp0 liblqr-1-0

  libmagickcore-6.q16-2 rake redmine redmine-sqlite ruby-actionmailer ruby-actionpack

  ruby-actionpack-action-caching ruby-actionview ruby-activemodel ruby-activerecord

  ruby-activesupport ruby-arel ruby-atomic ruby-awesome-nested-set ruby-blankslate ruby-builder

  ruby-celluloid ruby-coderay ruby-coffee-rails ruby-coffee-script ruby-coffee-script-source

  ruby-dev ruby-erubis ruby-execjs ruby-fcgi ruby-ffi ruby-hike ruby-hmac ruby-i18n

  ruby-jbuilder ruby-jquery-rails ruby-json ruby-listen ruby-mail ruby-mime-types ruby-minitest

  ruby-multi-json ruby-net-http-persistent ruby-net-ldap ruby-oj ruby-openid ruby-passenger

  ruby-polyglot ruby-protected-attributes ruby-rack ruby-rack-openid ruby-rack-test ruby-rails

  ruby-rails-observers ruby-railties ruby-rb-inotify ruby-redcarpet ruby-request-store

  ruby-rmagick ruby-sass ruby-sass-rails ruby-sdoc ruby-spring ruby-sprockets

  ruby-sprockets-rails ruby-sqlite3 ruby-thor ruby-thread-safe ruby-tilt ruby-timers

  ruby-treetop ruby-turbolinks ruby-tzinfo ruby-uglifier ruby-yajl ruby2.1-dev sqlite3 zip

0 upgraded, 93 newly installed, 0 to remove and 0 not upgraded.

Need to get 850 kB/21.7 MB of archives.

After this operation, 83.3 MB of additional disk space will be used.

Do you want to continue? [Y/n] 

$ sudo apt-get install apache2 mysql-server redmine redmine-mysql libapache2-mod-passenger

$ sudo ln -s /usr/share/redmine/public /var/www/redmine

$ sudo chown -R www-data:www-data /var/www/redmine

$ sudo vi /etc/apache2/sites-available/redmine.conf

DocumentRoot /var/www/

PassengerDefaultUser www-data

<Location /redmine>

RailsEnv production

RackBaseURI /redmine

Options -MultiViews

</Location>

$ sudo a2dissite 000-default

$ sudo a2ensite redmine

$ sudo /etc/init.d/apache2 reload

$ sudo /etc/init.d/apache2 restart 

-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 that were used to generate code (-fpic, -fPIC, or model suboptions) when you specify this option.[1]

-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 and 32k on the m68k and RS/6000 . The 386 has no such limit.)

Position-independent code requires special support, and therefore works only on certain machines. For the 386, 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.

-fPIC

If supported for the target machine, emit position-independent code, suitable for dynamic linking and avoiding any limit on the size of the global offset table. This option makes a difference on the m68k, PowerPC and SPARC .

Position-independent code requires special support, and therefore works only on certain machines.

When this flag is set, the macros "__pic__" and "__PIC__" are defined to 2.

-fpie

-fPIE

These options are similar to -fpic and -fPIC, but generated position independent code can be only linked into executables. Usually these options are used when -pie GCC option will be used during linking.

-fpie and -fPIE both define the macros "__pie__" and "__PIE__". The macros have the value 1 for -fpie and 2 for -fPIE. 

Pseudo-assembly:

PIC: This would work whether the code was at address 100 or 1000

100: COMPARE REG1, REG2

101: JUMP_IF_EQUAL CURRENT+10

...

111: NOP

Non-PIC: This will only work if the code is at address 100

100: COMPARE REG1, REG2

101: JUMP_IF_EQUAL 111

...

111: NOP

If your code is compiled with -fPIC, it's suitable for inclusion in a library - the library must be able to be relocated from its preferred location in memory to another address, there could be another already loaded library at the address your library prefers. 

class Something

{

private:

    int m_value1;

    double m_value2;

    char m_value3;

public:

    Something() : m_value1(1), m_value2(2.2), m_value3('c') // directly initialize our member variables

    {

    // No need for assignment here

    }

    void print()

    {

         std::cout << "Something(" << m_value1 << ", " << m_value2 << ", " << m_value3 << ")\n";

    }

};

int main()

{

    Something something;

    something.print();

    return 0;

}