C++ Smart Pointers: From Basics to Advanced
May 09, 2024 pm 09:27 PMSmart pointers are C-specific pointers that can automatically release heap memory objects and avoid memory errors. Types include: unique_ptr: exclusive ownership, pointing to a single object. shared_ptr: shared ownership, allowing multiple pointers to manage objects at the same time. weak_ptr: Weak reference, does not increase the reference count and avoid circular references. Usage: Create smart pointers using make_unique, make_shared and make_weak of the std namespace. Smart pointers automatically release object memory when the scope ends. Advanced usage: You can use custom deleters to control how objects are released. Smart pointers can effectively manage dynamic arrays and prevent memory leaks.
From basic to advanced: C smart pointers
Introduction
Smart pointers It is a special pointer in C designed to solve memory management. They effectively avoid common memory errors caused by manual memory management, such as memory leaks and dangling pointers, by automatically releasing the space pointed by the pointer to the object on the heap memory.
Types
There are multiple smart pointer types in C, each with its own unique capabilities and uses:
- unique_ptr: A smart pointer with exclusive ownership, pointing to an object that can only be managed by one pointer.
- shared_ptr: A smart pointer that shares ownership, allowing multiple pointers to manage the same object at the same time.
- weak_ptr: Weak reference smart pointer does not increase the reference count of the object and is used to avoid circular references.
Basic usage
To create a smart pointer just use the corresponding type template in the std
namespace:
// 獨(dú)占所有權(quán) unique_ptr<int> p1 = make_unique<int>(42); // 共享所有權(quán) shared_ptr<int> p2 = make_shared<int>(10); // 弱引用 weak_ptr<int> p3 = p2;
Release memory
A smart pointer will automatically release the object it points to when its scope ends. Therefore, there is no need to manually call delete
or free
.
Practical case: dynamic array management
Using smart pointers to manage dynamic arrays can avoid memory leaks caused by forgetting to manually release space:
// 普通的動(dòng)態(tài)數(shù)組管理 int* arr = new int[100]; // 智能指針管理動(dòng)態(tài)數(shù)組 unique_ptr<int[]> arr = make_unique<int[]>(100);
Smart pointers automatically delete the array when arr
exceeds its scope. This ensures that resources are released in all cases.
Advanced usage: Custom deleter
In some cases, you may need to use a custom deleter to control how the object pointed to by the pointer is released. This can be achieved by overloading the delete
operator:
class MyObject { public: ~MyObject() { // 自定義刪除邏輯 } }; int main() { unique_ptr<MyObject, decltype(&MyObject::delete)> p = make_unique<MyObject>(&MyObject::delete); }
Conclusion
By incorporating smart pointers into the C code base, developers can significantly Improve memory management efficiency while avoiding common mistakes. This helps build more robust and reliable applications.
The above is the detailed content of C++ Smart Pointers: From Basics to Advanced. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

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

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

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

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

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

Hot Topics

People who study Python transfer to C The most direct confusion is: Why can't you write like Python? Because C, although the syntax is more complex, provides underlying control capabilities and performance advantages. 1. In terms of syntax structure, C uses curly braces {} instead of indentation to organize code blocks, and variable types must be explicitly declared; 2. In terms of type system and memory management, C does not have an automatic garbage collection mechanism, and needs to manually manage memory and pay attention to releasing resources. RAII technology can assist resource management; 3. In functions and class definitions, C needs to explicitly access modifiers, constructors and destructors, and supports advanced functions such as operator overloading; 4. In terms of standard libraries, STL provides powerful containers and algorithms, but needs to adapt to generic programming ideas; 5

C STL is a set of general template classes and functions, including core components such as containers, algorithms, and iterators. Containers such as vector, list, map, and set are used to store data. Vector supports random access, which is suitable for frequent reading; list insertion and deletion are efficient but accessed slowly; map and set are based on red and black trees, and automatic sorting is suitable for fast searches. Algorithms such as sort, find, copy, transform, and accumulate are commonly used to encapsulate them, and they act on the iterator range of the container. The iterator acts as a bridge connecting containers to algorithms, supporting traversal and accessing elements. Other components include function objects, adapters, allocators, which are used to customize logic, change behavior, and memory management. STL simplifies C

In C, cin and cout are used for console input and output. 1. Use cout to read the input, pay attention to type matching problems, and stop encountering spaces; 3. Use getline(cin, str) when reading strings containing spaces; 4. When using cin and getline, you need to clean the remaining characters in the buffer; 5. When entering incorrectly, you need to call cin.clear() and cin.ignore() to deal with exception status. Master these key points and write stable console programs.

InheritanceinC allowsaderivedclasstoinheritpropertiesandbehaviorsfromabaseclasstopromotecodereuseandreduceduplication.Forexample,classeslikeEnemyandPlayercaninheritsharedfunctionalitysuchashealthandmovementfromabaseCharacterclass.C supportssingle,m

FunctionhidinginC occurswhenaderivedclassdefinesafunctionwiththesamenameasabaseclassfunction,makingthebaseversioninaccessiblethroughthederivedclass.Thishappenswhenthebasefunctionisn’tvirtualorsignaturesdon’tmatchforoverriding,andnousingdeclarationis

volatile tells the compiler that the value of the variable may change at any time, preventing the compiler from optimizing access. 1. Used for hardware registers, signal handlers, or shared variables between threads (but modern C recommends std::atomic). 2. Each access is directly read and write memory instead of cached to registers. 3. It does not provide atomicity or thread safety, and only ensures that the compiler does not optimize read and write. 4. Constantly, the two are sometimes used in combination to represent read-only but externally modifyable variables. 5. It cannot replace mutexes or atomic operations, and excessive use will affect performance.

There are mainly the following methods to obtain stack traces in C: 1. Use backtrace and backtrace_symbols functions on Linux platform. By including obtaining the call stack and printing symbol information, the -rdynamic parameter needs to be added when compiling; 2. Use CaptureStackBackTrace function on Windows platform, and you need to link DbgHelp.lib and rely on PDB file to parse the function name; 3. Use third-party libraries such as GoogleBreakpad or Boost.Stacktrace to cross-platform and simplify stack capture operations; 4. In exception handling, combine the above methods to automatically output stack information in catch blocks

To call Python code in C, you must first initialize the interpreter, and then you can achieve interaction by executing strings, files, or calling specific functions. 1. Initialize the interpreter with Py_Initialize() and close it with Py_Finalize(); 2. Execute string code or PyRun_SimpleFile with PyRun_SimpleFile; 3. Import modules through PyImport_ImportModule, get the function through PyObject_GetAttrString, construct parameters of Py_BuildValue, call the function and process return
