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Posts tagged howto
Getting started with pthread
Sep 25th
Recently i have started coding in C a lot and what i came across from a lot of people is that doing Threading in C is very hard, is it really like that? here is a simple Pthread program that should clear that up
get it here
in the above program i have just created 2 threads and passed thr1 ( = 1 ) and thr2 ( = 2 ) values as parameters the function void * thread ( void * ptr ) is executes as a separate thread, we create two thread objects thread1 and thread2, and start threads using pthread_create function passing thread object, function pointer and parameters as arguments, here NULL specifies default attributes for the thread, we can change this by passing pthread_attr_t structure instead of NULL.
we wait for the threads to finish using the pthread_join function
One major problem that is faced by most of the people is of using a library which is not a thread safe library, so you need to be careful about the libraries you use in your program, if not sure about a particular library being thread safe, just assume it not to be thread safe
PS – No updates from a long time as i dont have a proper net connection ….
Creating your own service like tinyurl
May 24th
Few weeks ago i came across this article on Techcrunch which says tinyurl is worth $46Million (of course before twitter started using bit.ly as default) which made me think how hard is it to make a simple service like tinyurl and i figured out its not hard. so i used apache’s mod_rewrite to rewrite the url and forward the code to a php script ( url.php ) which will then search for the url in database and take the use to the original url and for shorting, url it is inserted into a table with a auto increment primary key and the key is converted to base36 which contains [a-z] and [0-9], making the short code…
First create a database say ‘shorturl’
CREATE TABLE IF NOT EXISTS `shorturl` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`url` varchar(300) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;
then create file .htaccess where you want your url to be and write
RewriteEngine On
RewriteCond %{REQUEST_URI} \/([0-9a-z]*)$ [NC]
RewriteRule ^(.*) url.php?url=%1 [L]
and to create the url we will use a simple file say create.php
<html>
<head>
<title>Url Shortner</title>
</head>
<body>
<?php
ob_start();
$host=""; //host
$dbuser=""; // database username
$dbpass=""; // database password
$db=""; //database name
$con = mysql_connect($host,$dbuser,$dbpass);
mysql_select_db("url",$con);
if (!isset($_POST['shorten']))
{
echo "<center><h3>Enter the url to shorten</h3><form method='POST'><input type='text' name='url' />
<input type='submit' name='shorten' value='Shorten' /></form></center>";
}
else
{
if (isset($_POST['url']))
{
$url=" ".mysql_real_escape_string($_POST['url']);
if (strpos($url,"http://") or strpos($url,"https://") or strpos($url,"ftp://"))
{
$url=mysql_real_escape_string($_POST['url']);
}
else
{
$url="http://".mysql_real_escape_string($_POST['url']);
}
$q="select * from url where url='{$url}'";
$res = mysql_query($q,$con);
$row=mysql_fetch_row($res);
if (!$row)
{
$query="insert into url set url='{$url}'";
$res = mysql_query($query,$con);
}
$query1="select id from url where url='{$url}' limit 1";
$res=mysql_query($query1,$con);
$row=mysql_fetch_row($res);
echo "shortened url is http://yoursite.com/".base_convert($row[0],10,36);
}
}
ob_end_flush();
?>
</body>
</html>
then our url.php file
<?php
ob_start();
$host=""; //host
$dbuser=""; // database username
$dbpass=""; // database password
$db=""; //database name
$con = mysql_connect($host,$dbuser,$dbpass);
mysql_select_db($db,$con);
if (isset($_GET['url']))
{
$query="select * from url where id ='".base_convert(mysql_real_escape_string($_GET['url']),36,10)."'";
$res = mysql_query($query,$con);
$row=mysql_fetch_row($res);
header("Location: ".$row[1]);
}
ob_end_flush();
?>
Download here
Synaptics Touchpad in Fedora 9
May 30th
I have been using Fedora 9 from a long time and it really kick’s ass but i was facing the problem that my Touchpad was not working with it but the i found the solution here
Here is how to do it
The easiest was will be to install the package http://atrpms.net/dist/f9/synaptics/
or you can do it manually here
edited the /etc/X11/xorg.conf
gedit /etc/X11/xorg.conf
Added the following to the ServerLayout Section
InputDevice “TouchPad” “CorePointer”
add a new section:
Section “InputDevice”
Driver “synaptics”
Identifier “TouchPad”
Option “SendCoreEvents”
Option “Protocol” “auto-dev”
Option “SHMConfig” “on”
Option “TapButton1″ “1″
Option “TapButton2″ “2″
EndSection
all done logout and login again and everything should be working fine
Update: found the rpm package here
