Sunday 28 October 2012

Compiling a Boost program

Here is a sample Filesystem tutorial program

http://www.boost.org/doc/libs/1_50_0/libs/filesystem/example/tut1.cpp

We will try to compile this program

So Assuming that you have installed boost libraries. If not then read my previous post

Now to compile any boost related program we will be needing the header files, the libraries and the boost_root folder. Boost_root folder is the folder from where you have installed boost. In my previous post my boost_root is boost_1_50_0. Next step is very easy you have to run the following command in Terminal.

g++ tut1.cpp -o first -lboost_filesystem -lboost_system -I path/to/boost_1_50_0

Feel free to comment if the above command is not working for you

Installing Boost 1.50 in Ubuntu 12.10

Source:http://ubuntuforums.org/showthread.php?t=1180792

I have made few changes

Welcome. This a guide on how to install the Boost libraries from source. Although the boost libraries are available in the universe repository there are people who have tried to install from source for one reason or another (myself included) and, because of the unfamiliar method by which Boost choose to create their libraries, fall into trouble or else never really understand what to do (even though it's not all that hard actually).
This is only a very simple guide on how to get the source compiled and installed and I wont go into more advanced topics on how to customize the installation (because I don't know myself) or on how to cross-compile (since I've tried and given up on that -- the problem being that the boost build system doesn't use the correct cross-compiling binaries for compiling and creating the libraries and it's next to Alchemy trying to understand how to get the thing to use the correct ones. As a last resort, not even creating symlinks from the the cross-compiling binary to the corresponding normal build binary didn't work!).

-1) General Information

This guide is specifically written for boost libraries version 1.39.0. The general idea of what we're doing will probably still apply for some of the more recent older library version; but, there will be crucial differences, like the fact that the file configure will exist instead of bootstrap.sh.

0) Pre-requisites

0.1)
You will need the necessary compiling tools (g++, ld, etc...); so, first, install them:
Code:
sudo apt-get install build-essential g++
0.2)
You will need the source code! Boost's website is not the best when it comes to finding where things are, so just navigate to their getting started page and under the section Get Boost follow the link to the download page and download tar.bz2 file (the tar.7z file has Windows line-terminators, so reading those files in Linux will cause errors). Incidentally, that getting started page is the general reference from which I've derived this guide (along with a bit of trial and much error).

1) Compile the library

1.1)
Go to where you downloaded the directory and uncompress it:
Code:
cd download_location
tar xjf boost_1_50_0.tar.bz2
Note that the uncompressed source is over 250Mb; so if space is an issue, make the necessary sacrifices!
Then change directory into the boost directory:
Code:
cd ./boost_1_50_0
1.2)
Next, we'll need to build the bjam binary and perhaps also set some options on what to compile and where to. Read the next three sub-sections carefully and read it all before you do anything! 

1.2.1)
Firstly, you will not want to compile the whole boost library since that means compiling a lot of libraries that you don't want or wont use. So, to see a list of the libraries that need compiling, run:
Code:
./bootstrap.sh --show-libraries
Pick which ones you want and remember them: I'll be choosing filesystemprogram_options and system. Note that picking system is needed since it contains the error class that filesystem uses, and I bet that, since the majority of you readers will be looking to compile the filesystem library, this means cutting a few problems out later on for a lot of you!
What you'll need to run is the command:
Code:
./bootstrap.sh --with-libraries=filesytem,program_options,system
But don't do that just yet: keep reading!
If you do want to compile the whole damned thing, then you don't need to bother with the command above: you'll just run bootstrap.sh as it is:
Code:
./bootstrap.sh
Again, don't run anything yet: still keep on reading!

1.2.2)
Next, you'll need to consider where you want the library installed to. By default, the header files are installed to /usr/local/include, and the libraries themselves are installed to /usr/local/lib. These locations will be more than adequate (it's not recommended to install stuff to /usr/include, /usr/include/lib or /lib); but, if you do want/need to specify a different location, you'll need to run bootstrap.sh like this:
Code:
./bootstrap --libdir=/my/lib/dir --includedir=/my/include/dir
which will install the libraries to /my/lib/dir and the header files to /my/include/dir.
Note: there is a bug in that the libraries are installed to /lib and not /usr/local/lib by default; so I'd recommend explicitly telling the build process to install to /usr/local/lib. Do this by adding the flag: --exec-prefix=/usr/local.
Still, don't run anything yet! Keep reading!

1.2.3)
OK, now bring the info from the last two sub-sections together: you'll want the command:
Code:
./bootstrap.sh --exec-prefix=/usr/local --with-libraries=desired_list_of_libs --libdir=/my/lib/dir --includedir=/my/include/dir
For example, I want to only install the filesystemprogram_options, and system libraries, and just to the default lib and include directories; so, I'll personally run:
Code:
./bootstrap.sh --with-libraries=filesystem,program_options,system --exec-prefix=/usr/local
Having done this (or something similar depending on what you want to do) you'll see the message:
Quote:
Bootstrapping is done. To build, run:

./b2

To adjust configuration, edit 'project-config.jam'.
Further information:

- Command line help:
./b2 --help

- Getting started guide:
http://www.boost.org/more/getting_st...-variants.html

- Boost.Build documentation:
http://www.boost.org/boost-build2/doc/html/index.html
At this point, you can then do the compiling proper...

1.2.4)
Run the command:
Code:
./b2
And that's it!

2) Installation

Immediately after compiling, and before we install them, the header files will be in the directory boost, and the libraries in the directory stage/lib. To install them, just run:
Code:
sudo ./b2 install
Note that, on my system, that command seems to hang for a while; so, give it a chance before killing it.

In my case there was no need to do this step as libboost_filesystem.so was already there in /usr/local/lib

Now, there is one "bug" in the installation process. The installation procedure does not create a symlink called libboost_filesystem.so. It's not really a problem, but it's very useful if it does exist. Look in your library directory to see if it's there, or else create it:
Code:
sudo ln -s /usr/local/lib/libboost_filesystem-gcc43-mt.so /usr/local/lib/libboost_filesystem.so
And change /usr/local/lib if you changed where you installed your libraries to at stage 1.2.3, and amend libboost_filesystem-gcc43-mt.so if it's different on your system. (Post a comment if you are having trouble with this since the names will probably be different from system-to-system and don't do anything if you're not at all sure on how libraries are named and symlinked).

3) Using the libraries

This bit normally causes a few problems, so read it carefully!

3.1)
Include your header files as usual in your code like:
Quote:
#include <boost/filesystem.hpp>
and then tell your compiler where the include libraries are with a -I flag:
Code:
g++ -I/usr/local/include/boost-1_39 ...
If you changed your include directory at stage 1.2.3 by issuing:
Quote:
./bootstrap.sh --includedir=/my/include/dir
then you'll need to amend the g++ command to:
Code:
g++ -I/my/include/dir/boost-1_39
3.2)
Then, we'll also need to make sure we can link to the libraries.
If you did not change the directory to where the libraries are installed to from the default at stage 1.2.3, then simply run:
Code:
sudo ldconfig

Note: If you are using Filesystem then also add lboost_system with it as it is dependent on it

And you can start linking the library as usual:
Code:
g++ -lboost_filesystem -lboost_system ...
If you did change the lib directory at stage 1.2.3 by running:
Quote:
./bootstrap.sh --libdir=/my/lib/dir
then you'll need to run the linking stage as:
Code:
g++ -L/my/lib/dir -lboost_filesystem
Hopefully, that's it! You should now be able to use boost!

So The final Code to be run on terminal will look something like this if you have not changed the installation directory on step 1.2.3

Sample.cpp //Sample program to check if boost is working or not
#include<boost/filesystem.hpp>
int main()
{
//anything here
return 0;
}

Code:
g++ -lboost_filesystem -lboost_system Sample.cpp
Feel free to comment below if I have missed something! Happy Coding

Always remember in perl

Use eq to compare string and == to compare numeric

Tuesday 16 October 2012

Need for Speed Most Wanted Lan Multiplayer problem

NFS MW is the best game ever made by EA that still millions are playing even after 7 years of its release. The best thing it had was the gameplay and the story. We often used to play LAN Multiplayer in it. But after installing Windows 7, most of the times it stopped working after connecting to the host player or while connecting to host player. The Need for speed is causing these problems because Windows is not providing him with enough privileges to connect to the port. So run it in as Administrator in Windows 7. Everything will work fine. :)