在php中动态创建文件的问题

I want to create File that have Full permission dynamically, that means every change for ID of session create new file . Unfortunately I faced some problem .

Warning: fopen(test.txt) [function.fopen]: failed to open stream: Permission denied in /home/teamroom/public_html/1/3.php on line 2

Warning: fwrite(): supplied argument is not a valid stream resource in /home/teamroom/public_html/1/3.php on line 3

Warning: fclose(): supplied argument is not a valid stream resource in /home/teamroom/public_html/1/3.php on line 4

code :

<?php
session();
$member_Id=$_SESSION['user_id'];
if (isset($member_Id)){
$file = fopen("test.txt","x+");
fwrite($file,"test");
fclose($file);
}
?>

can you help me ? or can you tell another way to do this idea ?

It would appear that the process PHP is running as (often the web server, e.g. www-data) does not have write permissions for the folder you're trying to create the file in (e.g. /home/teamroom/public_html/1/).

You also should be doing error checking on the fopen() call. Then there's the security assect to think of.

you have no permissions to access directory. Use php-function chmod ("/somedir/somefile", 755); or change directory permissions by ftp-client. And why are you trying to open file with x+ if you need only writing:
Modes:
r - Reading only, beginning of file
r+ - Reading and writing, beginning of file
w - Writing only, beginning of file
w+ - Writing and reading, beginning of file
a - Writing only, end of file
a+ - Writing and reading, end of file
x - Create and open for writing only, beginning of file
x+ - Create and open for reading and writing, beginning of file
If the file does not exist and you use w, w+, a or a+ it will attempt to create the file.
I think you can use w+ or a+

And for your another problem:

<?php
$fp = fopen ('/path/to/file', "r");
while (!feof ($fp))
{
    $value = fgets($fp);
    if(!empty($value))
    { 
       //Here do what you want with your value
    }
}
?>

This was string-by-string reading code. Also you can use file_get_contents(); php-function and work with it lika string.
P.S> Sorry for my english