13 managing resources by objects

Clause - 13 Manage resources with objects

Remember:

1- In order to prevent resource leakage , Please use RAII（ Resource acquisition initialization ） object , They take resources in constructors and release resources in destructors .

2- Two are often used RAII class Namely tr1::shared_ptr and auto_ptr. The former is usually the better choice , Because of its copy The behavior is more intuitive . If choose auto_ptr, The copy action makes it （ The copy ） Point to null.

​ So-called resources Namely , Once you use it , It must be returned to the system in the future .C++ The longest use is dynamic memory allocation , If not released , Will cause memory leaks .

​ This clause is for the assigned class object .

​ routine ： After using the object delete Its object . When the number of code is large, it is usually encapsulated with functions .

But there's a problem ： Sometimes before you can delete it , I met one of them return. This leads to a memory leak .

​ resolvent ：C++ Of “ Destructor automatic calling mechanism ”.

​ Two commonly used pointers ： auto_ptr、tr1::shared_ptr.

​ When used normally When the destructor is automatically deleted, the form of the two smart pointers is similar . But when using replication behavior to assign null When ,tr1::shared_ptr Obviously, it looks more comfortable .

​ 【 notes 】auto_ptr and tr1::shared_ptr All are done in the destructor delete instead of deletep[]. That means in dynamic allocation array Use on your body auto_ptr or shared_ptr It's a bad idea . In fact, the definition of vector、string It can replace array 了 .