In class_core.php, global $ _ G indicates the first time that a global variable is passed for the second time, instead of a global source: www. discuz. netforum. php? Modviewthread & amp; tid3007341 rating: global $ _ G meaning & nbsp; the first time to declare that this is a global variable, the second time to indicate that the variable is passed, without the definition of global $ _ G in class_core.php for the first time to declare that this is the second time that the global variable is passed, rather than the global variable
Source: http://www.discuz.net/forum.php? Mod = viewthread & tid = 3007341.
Rating: global $ _ G indicates the first time that a global variable is passed for the second time.
As you may find, the DZ plug-in has never been used. the meaning of this variable is explained as follows:
/Source/class/discuz/discuz_application.php (X2.5)
/Source/class/class_core.php (X2.0)
In the _ init_env () method of this file, global $ _ G is used to declare that this is a global variable, which stores the global information most frequently used by the system, this is mainly for the convenience of subsequent functions. For example, if I want to know the UID of the current user, I can simply read $ _ G ['uid'] without having to query the session or database twice, which improves the efficiency, write other program modules, and the amount of code will become very concise.
If you want to ask where the definition is, this is the section (omitted from a large section ):
Global $ _ G; // to declare that this is a global variable
$ _ G = array (
'Uid' => 0,
'Username' => '',
..................
);
In other files except this file, if global $ _ G is used, it indicates to pass this variable.
For example, in plug-in development, there is a method like this:
Function viewthread_postfooter_output (){
Global $ _ G; // indicates passing variables instead of declaring global variables.
Return $ _ G ['uid'];
}
For developers, the $ _ G variable has the meaning of "read-only". In other words, when no one writes a program, it can be initialized at will.
In addition, as a commercial institution rather than a public welfare scientific research institution, the staff are not obligated to tell you the meaning of the code. for the so-called readability, please learn more and understand it by yourself? This is like no hotel actively tells customers about the recipe of the dish.
