How do C++ smart pointers compare to smart pointers in other languages?

The implementation of smart pointers in different languages ​​varies. In C, smart pointers take exclusive ownership and use destructors to release resources. In Java, smart pointers do not have ownership and resources are released automatically by the garbage collector, but the release time is uncertain.

C smart pointers and smart pointers in other languages

A smart pointer is a pointer abstraction that is responsible for automatically managing memory. Although C provides a variety of smart pointer types, the implementation of smart pointers may vary in different languages.

Syntax comparison

In C, the syntax of smart pointers is as follows:

std::unique_ptr<T> ptr = std::make_unique<T>();

And in Java, the syntax of smart pointers is as follows:

Optional<T> ptr = Optional.of(new T());

Ownership

Smart pointers in C have exclusive ownership, which means other pointers to the object are invalid. In contrast, smart pointers in Java do not take ownership, which allows multiple references to an object to exist simultaneously.

Resource Management

C Smart pointers automatically release resources through the destructor. When a smart pointer goes out of scope or is explicitly released, the object pointed to will be destroyed.

Smart pointers in Java similarly release resources automatically through the garbage collector. However, garbage collection occurs at undetermined times, which can cause unexpected delays.

Practical case

Consider the following C code, which uses smart pointer managementstd::stringObject:

std::unique_ptr<std::string> name = std::make_unique<std::string>("John");

When When name goes out of scope, the smart pointer pointing to the std::string object is automatically destroyed, freeing the memory.

In Java, the following code similarly uses smart pointers to manage String objects:

Optional<String> name = Optional.of(new String("John"));

When name goes out of scope, the garbage collector The String object's memory will be released, but at an undetermined time.

The above is the detailed content of How do C++ smart pointers compare to smart pointers in other languages?. For more information, please follow other related articles on the PHP Chinese website!