Home What purpose does a $$(double dollar) serve in the context of mysql? Reply: 1 # What purpose does a$$ (double dollar) serve in the context of mysql?

Jordan
1#
Jordan Published in 2018-02-14 16:42:40Z
 This question already has an answer here: Reference — What does this symbol mean in PHP? 18 answers What does $$(dollar dollar or double dollar) mean in PHP? 6 answers I am using old code for a login process that accesses a local database. This is the first web project that I would like to put online. The code that I started with had deprecated functions so I've been trying to get everything up and running and gain an understanding of the language/process. The original developers used a variable link and two lines later they declare a global$$link. (EDIT: Since I first posted I learned about a variable variable, but I still fully understand this use case. What could it be used for) tep_db_connect() or die('Unable to connect to database server!'); function tep_db_connect($server = DB_SERVER,$username = DB_SERVER_USERNAME, $password = DB_SERVER_PASSWORD,$database = DB_DATABASE, $link = 'db_link') { global $$link;$$link = new mysqli($server, $username,$password); if (!$$link) { die("Connection Failed: " . mysqli_connect_error()); } mysqli_select_db($$link, $database); return $$link; }  This is my first web project. I'm used to using a debugger to figure things out. Carlos Rodrigues 2# Carlos Rodrigues Reply to 2018-02-14 16:51:27Z  I believe this can be considered "meta" programming, but as has been mentioned, this is a variable variable. An example to illustrate may be: a = '1'; b = 'a'; echo$$b; // result: 1, can effectively be read as${$b} ->${a} -> $a echo${\$b}; // same as above but a bit more obvious 
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