国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂

Home Backend Development C++ C++ smart pointers: a comprehensive analysis of their life cycle

C++ smart pointers: a comprehensive analysis of their life cycle

May 09, 2024 am 11:06 AM
c++ Scope smart pointer standard library

C Life cycle of smart pointers: Creation: Smart pointers are created when memory is allocated. Ownership transfer: Transfer ownership through a move operation. Release: Memory is released when a smart pointer goes out of scope or is explicitly released. Object destruction: When the pointed object is destroyed, the smart pointer becomes an invalid pointer.

C++ 智能指針:全面剖析其生命周期

C Smart pointer: comprehensive analysis of its life cycle

Introduction

Smart pointer A pointer is a special pointer used in C to manage dynamically allocated memory. Unlike raw pointers, smart pointers are responsible for tracking the memory state of the object they point to and automatically releasing that memory when the object is no longer needed. This helps prevent common programming errors such as memory leaks and dangling pointers.

Types

The C standard library provides four main types of smart pointers:

  • ##unique_ptr:Unique ownership pointer. Only one unique_ptr can point to an object at a time.
  • shared_ptr: Pointer to shared ownership. There can be multiple shared_ptr pointing to the same object.
  • weak_ptr: Weak reference pointer. weak_ptr does not prevent the object from being destroyed and needs to be used with shared_ptr.
  • auto_ptr: Deprecated. Removed in C 11.

Lifecycle

1. Creation

Smart pointers can be created when the object allocates memory, like Same as using raw pointers:

auto ptr = std::make_unique<int>(42);

2. Ownership transfer

Smart pointers can transfer ownership through move operations:

auto ptr2 = std::move(ptr);  // ptr2 現(xiàn)在擁有對整數(shù)對象的唯一所有權(quán)

3. Release

When a smart pointer leaves its scope or is explicitly released, it will release the memory it owns:

{
    auto ptr = std::make_unique<int>(42);
    // ...
}  // ptr 在此處釋放

4. Object destruction

When the object pointed to is destroyed, the smart pointer will become an invalid pointer:

int* ptr = new int(42);
auto sptr = std::make_shared<int>(ptr);
delete ptr;  // ptr 被銷毀
sptr->get();  // sptr 現(xiàn)在指向一個無效指針,因此 get() 會拋出異常

Practical case

The following is how to use smart pointers to manage Dynamically allocated array:

// 原始指針版本
int* arr = new int[10];  // 分配數(shù)組

// ...

delete[] arr;  // 釋放數(shù)組

// 智能指針版本
std::unique_ptr<int[]> arr = std::make_unique<int[]>(10);  // 分配數(shù)組

// ...

// arr 在離開范圍時自動釋放

The smart pointer version is safer as it prevents memory leaks and dangling pointers.

The above is the detailed content of C++ smart pointers: a comprehensive analysis of their life cycle. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undress AI Tool

Undress AI Tool

Undress images for free

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

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

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

How to correctly handle this pointing in a closure? How to correctly handle this pointing in a closure? May 21, 2025 pm 09:15 PM

The methods to correctly handle this pointing in JavaScript closures include: 1. Use arrow functions, 2. Use bind methods, 3. Use variables to save this. These methods ensure that this intrinsic function correctly points to the context of the external function.

The difference between programming in Java and other languages ??Analysis of the advantages of cross-platform features of Java The difference between programming in Java and other languages ??Analysis of the advantages of cross-platform features of Java May 20, 2025 pm 08:21 PM

The main difference between Java and other programming languages ??is its cross-platform feature of "writing at once, running everywhere". 1. The syntax of Java is close to C, but it removes pointer operations that are prone to errors, making it suitable for large enterprise applications. 2. Compared with Python, Java has more advantages in performance and large-scale data processing. The cross-platform advantage of Java stems from the Java virtual machine (JVM), which can run the same bytecode on different platforms, simplifying development and deployment, but be careful to avoid using platform-specific APIs to maintain cross-platformity.

How to create a SQLite database in Python? How to create a SQLite database in Python? May 23, 2025 pm 10:36 PM

Create a SQLite database in Python using the sqlite3 module. The steps are as follows: 1. Connect to the database, 2. Create a cursor object, 3. Create a table, 4. Submit a transaction, 5. Close the connection. This is not only simple and easy to do, but also includes optimizations and considerations such as using indexes and batch operations to improve performance.

Analyze the performance problems that maps may cause when expanding capacity in Go language Analyze the performance problems that maps may cause when expanding capacity in Go language May 23, 2025 pm 10:00 PM

In Go, the performance problem will be triggered when the map is expanded. The following measures can be avoided: 1. Estimate the map size and set the appropriate initial capacity; 2. Process data in batches to reduce the pressure of single-scaling expansion; 3. Use sync.Map to deal with high concurrency scenarios.

How to reduce the use of global variables in C? How to reduce the use of global variables in C? May 23, 2025 pm 09:03 PM

Reducing the use of global variables in C can be achieved by: 1. Using encapsulation and singleton patterns to hide data and limit instances; 2. Using dependency injection to pass dependencies; 3. Using local static variables to replace global shared data; 4. Reduce the dependence of global variables through namespace and modular organization of code.

c: What does it mean? Data bit c Median domain definition colon usage c: What does it mean? Data bit c Median domain definition colon usage May 23, 2025 pm 08:48 PM

In C, the bit field is a structure member that specifies the number of bits, used to save memory and directly manipulate hardware. Example: structMyStruct{inta:2;intb:5;intc:1;}. The advantage of bit domains is memory savings, but there are cross-platform issues, access restrictions and assignments that require caution. Example of usage: structStateMachine{unsignedintpower:1;unsignedintmode:2;unsignedinterror:1;}. Performance recommendations include arranging bit fields by size, avoiding overuse and adequate testing.

Usage of ? in c Analysis of three-item operator instance in c Usage of ? in c Analysis of three-item operator instance in c May 23, 2025 pm 09:09 PM

The syntax of the trigonometric operator in C is condition?expression1:expression2, which is used to select and execute different expressions according to the condition. 1) Basic usage example: intmax=(x>y)?x:y, used to select the larger value in x and y. 2) Example of nested usage: intresult=(a>0&&b>0)?a b:(a==0||b==0)?a*b:a-b, used to perform different operations according to different conditions. 3) Error handling example: std::stringerrorMessage=(errorCode==0)?"Successful&quo

Usage of c Typical application scenarios of logical non-operators Usage of c Typical application scenarios of logical non-operators May 23, 2025 pm 08:42 PM

The usage of logical non-operator! in C includes: 1) Basic usage: inverse the Boolean value; 2) Conditional judgment: simplify the code, such as checking whether the container is empty; 3) Loop control: processing elements that do not meet the conditions; 4) Function return value processing: determine whether the operation has failed. Pay attention to potential pitfalls such as pointer processing and operator priority when using!, but it can help write more concise and efficient code.

See all articles