A problem with PHP references
See this word on the Internet
If a reference is assigned to an undefined variable, a reference parameter is passed, or a reference is returned, the variable is created automatically. and point to NULL
Often use isset to determine whether a value exists, if the direct output of a non-existent value will be an error.
But if I use the quoted way, whether it can replace isset, whether it will impress the performance
$id =&$_get[' id ']
This $_get[' ID '] does not exist and will not be an error, there is a reference to the variable $id
------to solve the idea----------------------
$id =& $_get[' id '];
And
$id = @$_get[' id '];
is equivalent to the $id
But $id =& $_get[' id ']; After
Any modification to the $id will affect the $_get[' id '), which may cause problems with other parts of the program that use $_get[' ID ']
If you just want to avoid Notice level errors, you don't have to do this.
It is necessary to determine whether the incoming parameters are correct, especially the single entry system, which affects the entire workflow.
