Php-manual Learning----"Language Reference"----"type"-----"Resource Resource Type"

August 24, 2017 11:29:36
1. Resource resource is a special variable that holds a reference to an external resource. Resources are created and used through specialized functions.
2. Because the resource type variable holds special handles for open files, database connections, graphics canvas areas, and so on, it makes no sense to convert other types of values to resources.
3. Since the PHP 4 Zend engine introduced a reference counting system, it is possible to automatically detect that a resource is no longer referenced (as in Java). In this case, all external resources used by this resource will be released by the garbage collection system. Therefore, it is seldom necessary to manually free up memory.
4. Persistent database connections are special, they are not destroyed by the garbage collection system

Summary: Indicates that this resource type is not yet well understood.

Php-manual Learning----"Language Reference"----"type"-----"Resource Resource Type"