Objects
In response to yasuo_ohgaki, the reason for the inability of the $_SESSION[] variable to hold references is because a session is just a serialize()'d version of it's member variables saved under a unique filename, with this filename following the user around.
$_SESSION[] is therefore limited by the constraints of the serialize() function
Although this is not <i>strictly</i> true, ($_SESSION does some handling to convert messy variables (e.g. "s and ;s)) it cannot store resources due to the serialise() function's dependancy
Resources
A resource is a special variable, holding a reference to an external resource. Resources are created and used by special functions. See the appendix for a listing of all these functions and the corresponding resource types.
Note: The resource type was introduced in PHP 4
See also the get_resource_type() function.
Converting to resource
As resource variables hold special handlers to opened files, database connections, image canvas areas and the like, converting to a resource makes no sense.
Freeing resources
Thanks to the reference-counting system introduced with PHP 4's Zend Engine, a resource with no more references to it is detected automatically, and it is freed by the garbage collector. For this reason, it is rarely necessary to free the memory manually.
Note: Persistent database links are an exception to this rule. They are not destroyed by the garbage collector. See the persistent connections section for more information.
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User Contributed NotesResources
evildictaitor at hotmail dot com
17-Aug-2004 01:25
17-Aug-2004 01:25
isaac at chexbox dot com
23-Jun-2002 04:37
23-Jun-2002 04:37
For the the oblivious: An example of a resource would be a mysql database connection.
$result = mysql_connect("localhost", "username", "pass");
//$result variable is a resource.
print $result;
//will print: Resource ID#1, or something similar