2, function transfer address transfer I won’t go into details about call by address. The code is given directly below.
Note: If you test(1); here, an error will occur. 3, function reference returns
Explanation: In this way, $a=test(); actually does not get a function reference return, which is no different from an ordinary function call. As for the reason: PHP regulations PHP stipulates that what is obtained through $a=&test(); is the reference return of the function. As for what is a reference return (the PHP manual says: Reference return is used when you want to use a function to find which variable the reference should be bound to.). $a=test() method of calling a function only assigns the value of the function to $a, and any changes to $a will not affect $b in the function. When calling a function through $a=&test(), its function is to point the memory address of the $b variable in return $b and the memory address of the $a variable to the same place. That is to say, the effect equivalent to this is produced ($a=&b;), so changing the value of $a also changes the value of $b, so after executing
The above code is the effect of running in PHP5 In PHP5, object copying is achieved through references. In the above column, $b=new a; $c=$b; is actually equivalent to $b=new a; $c=&$b; The default in PHP5 is to call objects by reference, but sometimes you may want to create a copy of the object and hope that changes to the original object will not affect the copy. For this purpose, PHP defines a special method called __clone . 5, the role of quotes If the program is relatively large, there are many variables referencing the same object, and you want to manually clear the object after using it, I personally recommend using the "&" method, and then using $var=null to clear it. Otherwise, use the default of php5 Method. In addition, for transferring large arrays in php5, it is recommended to use the "&" method, after all, it saves memory space. 6, unquote When you unset a reference, you just break the binding between the variable name and the variable's contents. This does not mean that the variable contents are destroyed. For example:
will not unset $b, Just $a. 7, global reference When you declare a variable with global $var you actually create a reference to the global variable. It's the same as this:
This means that, for example, unset $var will not unset a global variable. $this In an object method, $this is always a reference to the object that calls it. The pointing (similar to pointer) function of the address in php is not implemented by the user himself, but is implemented by the Zend core. The reference in php adopts the principle of "copy-on-write", that is, unless a write operation occurs, it points to the same Address variables or objects will not be copied. 1, if you have the following code $a="ABC"; $b=$a;In fact, at this time, $a and $b both point to the same memory address, rather than $a and $b occupying different memories 2. If you add the following code to the above code $a="EFG";Since the data in the memory pointed to by $a and $b needs to be rewritten, the Zend core will automatically determine at this time to automatically produce a data copy of $a for $b and re-apply for a piece of memory for storage. This is about the usage of the reference symbol & in php. I hope it can help everyone. Articles you may be interested in: Detailed explanation of examples of php reference passing by value Example code quoted by php Detailed explanation of examples quoted by php Explanation about PHP references Example analysis of PHP variable references, function addresses and object references Detailed introduction to php reference passing by value Understand the difference between passing by value and passing by reference in PHP through examples Look at the efficiency issues of php address reference through examples About the problem of changing the variable value of the php reference address Quotes in PHP, "&" explanation |

To protect the application from session-related XSS attacks, the following measures are required: 1. Set the HttpOnly and Secure flags to protect the session cookies. 2. Export codes for all user inputs. 3. Implement content security policy (CSP) to limit script sources. Through these policies, session-related XSS attacks can be effectively protected and user data can be ensured.

Methods to optimize PHP session performance include: 1. Delay session start, 2. Use database to store sessions, 3. Compress session data, 4. Manage session life cycle, and 5. Implement session sharing. These strategies can significantly improve the efficiency of applications in high concurrency environments.

Thesession.gc_maxlifetimesettinginPHPdeterminesthelifespanofsessiondata,setinseconds.1)It'sconfiguredinphp.iniorviaini_set().2)Abalanceisneededtoavoidperformanceissuesandunexpectedlogouts.3)PHP'sgarbagecollectionisprobabilistic,influencedbygc_probabi

In PHP, you can use the session_name() function to configure the session name. The specific steps are as follows: 1. Use the session_name() function to set the session name, such as session_name("my_session"). 2. After setting the session name, call session_start() to start the session. Configuring session names can avoid session data conflicts between multiple applications and enhance security, but pay attention to the uniqueness, security, length and setting timing of session names.

The session ID should be regenerated regularly at login, before sensitive operations, and every 30 minutes. 1. Regenerate the session ID when logging in to prevent session fixed attacks. 2. Regenerate before sensitive operations to improve safety. 3. Regular regeneration reduces long-term utilization risks, but the user experience needs to be weighed.

Setting session cookie parameters in PHP can be achieved through the session_set_cookie_params() function. 1) Use this function to set parameters, such as expiration time, path, domain name, security flag, etc.; 2) Call session_start() to make the parameters take effect; 3) Dynamically adjust parameters according to needs, such as user login status; 4) Pay attention to setting secure and httponly flags to improve security.

The main purpose of using sessions in PHP is to maintain the status of the user between different pages. 1) The session is started through the session_start() function, creating a unique session ID and storing it in the user cookie. 2) Session data is saved on the server, allowing data to be passed between different requests, such as login status and shopping cart content.

How to share a session between subdomains? Implemented by setting session cookies for common domain names. 1. Set the domain of the session cookie to .example.com on the server side. 2. Choose the appropriate session storage method, such as memory, database or distributed cache. 3. Pass the session ID through cookies, and the server retrieves and updates the session data based on the ID.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Zend Studio 13.0.1
Powerful PHP integrated development environment

SublimeText3 Chinese version
Chinese version, very easy to use

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

SublimeText3 Mac version
God-level code editing software (SublimeText3)