This function is EXPERIMENTAL. The behaviour of this function, the name of this function, and anything else documented about this function may change in a future release of PHP without notice. Be warned and use this function at your own risk.
The function parses the XML document in str and returns a tree PHP objects as the parsed document. This function is isolated from the other functions, which means you cannot access the tree with any of the other functions. Modifying it, for example by adding nodes, makes no sense since there is currently no way to dump it as an XML file. However this function may be valuable if you want to read a file and investigate the content.