Archive for November, 2007

LDBL_MAX -1.#QNAN0e+000 with MinGW?

Author: Gui Guan

22 Nov

I have tried to run this with both eclipse(CDT)+MinGW and Cygwin+GCC

#include <stdio.h>
#include <stdlib.h>
#include <float.h>
 
int main()
  {
    puts("The range of ");
    printf("\tlong double is [%Le, %Le]∪[%Le, %Le]\n", -LDBL_MAX, -LDBL_MIN, LDBL_MIN, LDBL_MAX);
    return EXIT_SUCCESS;
  }

but got different results:

In eclipse(CDT)+MinGW
The range of
long double is [-1.#QNAN0e+000, 3.237810e-319]∪[6.953674e-310, 0.000000e+000]
In Cygwin+GCC
The range of
long double is [-1.189731e+4932, -3.362103e-4932]∪[3.362103e-4932, 1.189731e+4932]

This is weird, and I googled it, then just found this http://www.thescripts.com/forum/thread498535.html

The LDBL_MAX of long double is machine-dependent, but why it like this in same machine? I guess it’s the problem with MinGW. Anyone hv any idea?

2 Comments

Filed under: C

Append Session ID(SID) to Url Automatically When Cookies Are Forbidden

Author: Gui Guan

14 Nov

Today, when I was reviewing the session part of PHP, I suddenly came out a question: how to make PHP to append session ID(SID) to your page links automatically when cookies are forbidden in that browser? I managed to do this in JSP, but not sure whether the PHP can also handle this problem.

I checked the configuration files (php.ini) for my apache server, and there is a session section, under which there is a setting session.use_trans_sid = 0. After I changed this to session.use_trans_sid = 1, and restarted apache, the links of the page which invoked session_start() have now appended the SID. There is also an url_rewriter.tags, with which you can define what elements of a page will be appended.

Here are some demo codes:

sessions.php

<?php ob_start(); ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
	<title>Untitled</title>
</head>
 
<body>
<?php
	ini_set('session.use_trans_sid','1'); //you can also do this instead of modify php.ini
	session_start();
	$_SESSION['test']='right!';
	//header('Location: sessions2.php'); //SID won't be appended in this situation
	//exit();
?>
<a href="sessions2.php">click here</a>
</body>
</html>
<?php ob_end_flush(); ?>

sessions2.php

<?php ob_start(); ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
	<title>Untitled</title>
</head>
 
<body>
<?php
	session_start();
	echo $_SESSION['test'];
?>
 
</body>
</html>
<?php ob_end_flush(); ?>

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Archive for November, 2007

LDBL_MAX -1.#QNAN0e+000 with MinGW?

Append Session ID(SID) to Url Automatically When Cookies Are Forbidden

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