tutorial on summarizing instance usage of write-time replication

The problem introduces the assignment and the reference problem in PHP <?php$a = 10;//assigns a constant value to a variable, allocates a memory space for a $b = $a;//variable is assigned to the variable, is not copy a copy, B also allocated memory space? $c = & $a;//references do not allocate space for C, and C and a share a portion of space.?> What is your answer to the question in the middle? Before today, my answer is to allocate memory space for B. Because I understand this: & assigns a value, as a variable defines an alias, and adds a reference to the memory space. Changing one of these will affect the other references. 　　When using unset (), only a reference to the variable memory space is broken, and the memory space is not freed. and = Assignment is different, it will re-open a memory space to store a copy of the original variable.　　The changes between the two do not affect each other. And the following procedure confirms this.

1. Code instance sharing for write-time copy (copy on write) in PHP

Introduction: Problem Introduction First Look at the assignment and reference problem in PHP What's your answer to that question in the middle? Before today, my answer is to allocate memory space for B. Because I understand that: & Assignment

2. PHP garbage collection mechanism----copy and reference count at write time

Introduction:: This article mainly introduces the PHP garbage collection mechanism----write copy and reference count, for the PHP tutorial interested students can refer to.

3. Reference counters and copy-on-write for PHP variables

Introduction:: This article mainly introduces the PHP variable reference counter and write-time replication, for the PHP tutorial interested students can refer to.

4. PHP Bottom-up analysis: On-write replication Cow Cow of the plural win color forum ww7349cow Japan Cow Milk Stone

Introduction: cow,php:php Underlying analysis: About cow:data-id= "1190000004926603" on write-up > Want to go to the ceiling of technology, then the learning process lies in knowing it and knowing why. Today, let's talk about PHP's underlying write-time replication (also called split at write time). First, let's take a look at a piece of code: the output of two pieces of code I'm sure you all know, but let's talk about what's going on here today. Is the structure of the PHP storage variable (for ease of interpretation has written comments), zend.h in the Zend directory. As you can see, the struct stores the value of the variable, with several variables pointing to the

5. Strange phenomena during the foreach Traversal (PHP5)

Description:: A strange phenomenon during the foreach Traversal (PHP5): data-id= "1190000005044925" data-license= "sa" >php the three pits in the foundation, the foreach traversal, the reference mechanism &, and the array. Today we are talking about some strange phenomena in the foreach. Before the explanation, you can look at my other related articles, belong to the same big knowledge point, all look helpful to understand. What happens internally when we use foreach? (PHP5) PHP Bottom-up analysis: About write-time replication (cow) PHP bottom-up analysis: about forcing

6. PHP Principles of memory management difficult to understand a few points _php tutorial

Introduction: PHP Principles of memory management is difficult to understand a few points. PHP memory management, divided into two parts, the first part is the memory management of PHP itself, this part of the main content is the reference count, write-time replication, and so on application-oriented aspects of management. and the first

7. PHP Source code Analysis-variable reference count, copy-on-write (Reference counting &amp; copy-on-wr_php Tutorials

Introduction: PHP Source code Analysis-variable reference count, copy-on-write (Reference counting &amp; Copy-on-wr. There are two ways to assign values in PHP syntax: reference assignment, non-reference assignment. php $a = 1; $b = $a; Non-reference assignment $c = $b; Reference assignment? php $a = 1; $b = $a; Non-reference assignment $c

8. Understanding PHP Reference count and copy-on-write _php tutorials

Summary: Understand PHP reference counts and write-time replication. PHP uses reference counts and write-time replication (Copy-on-write) to manage memory. Reference calculations ensure that memory is returned to the operating system when the reference is no longer needed, and copy-on-write ensures that the variables are re-

9. PHP write-on-copy introduction (copy on write) _php tutorial

Introduction: PHP's write-On-copy introduction (copy on Write). Before we begin, we can look at a simple code: Copy the Code as follows: PHP//Example One $foo = 1; $bar = $foo; echo $foo + $bar;? Execute this code, print out the number

Introduction to copy on write in PHP _php tutorial

Introduction: The Copy-on-write mechanism is introduced in PHP. What is write-time replication (copy on write)? A: When copying an object, the original object is not actually copied to another location in memory, but within the new object

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