mirror of
https://github.com/adambard/learnxinyminutes-docs.git
synced 2024-12-23 09:41:36 +00:00
Minor fixes to C++ Smart Pointer section
* Fix minor spelling / grammar problems ("tp de-allocate", "refences", "dont"...) * Remove filler words ("Basically", "As a matter of fact"...) * Remove spaces before parens in smart pointer initialization code sample (consistent with the other sections, e.g. the `Tuples` section) * Clarify `std::weak_ptr` use case
This commit is contained in:
parent
4e8e92eb0e
commit
43fc3289dc
@ -818,51 +818,51 @@ void doSomethingWithAFile(const std::string& filename)
|
||||
// Smart Pointer
|
||||
/////////////////////
|
||||
|
||||
// Generally a smart pointer is a class, which wraps a "raw pointer" (usage of "new"
|
||||
// Generally a smart pointer is a class which wraps a "raw pointer" (usage of "new"
|
||||
// respectively malloc/calloc in C). The goal is to be able to
|
||||
// manage the lifetime of the object being point to without explicitly deleting
|
||||
// manage the lifetime of the object being pointed to without ever needing to explicitly delete
|
||||
// the object. The term itself simply describes a set of pointers with the
|
||||
// mentioned abstraction.
|
||||
// Basically smart pointers should preferred over raw pointers, to prevent
|
||||
// risky memory leaks, which happens if you forget to delete the object.
|
||||
// Smart pointers should preferred over raw pointers, to prevent
|
||||
// risky memory leaks, which happen if you forget to delete an object.
|
||||
|
||||
// Usage of a raw pointer:
|
||||
Dog* ptr = new Dog();
|
||||
ptr->bark();
|
||||
delete ptr;
|
||||
|
||||
// With the usage of smart pointers you dont have to worry about the deletion
|
||||
// of a object anymore.
|
||||
// A smart pointer describes a policy, to count the references on the
|
||||
// pointer. As matter of fact the objects gets destroyed when the last
|
||||
// reference on the object gets destroyed.
|
||||
// By using a smart pointer, you don't have to worry about the deletion
|
||||
// of the object anymore.
|
||||
// A smart pointer describes a policy, to count the references to the
|
||||
// pointer. The object gets destroyed when the last
|
||||
// reference to the object gets destroyed.
|
||||
|
||||
// Usage of "std::shared_ptr":
|
||||
void foo()
|
||||
{
|
||||
// Its not longer necessary to delete the Dog.
|
||||
// It's no longer necessary to delete the Dog.
|
||||
std::shared_ptr<Dog> doggo(new Dog());
|
||||
doggo->bark();
|
||||
}
|
||||
|
||||
// Beware of possible circular references!!!
|
||||
// There will be always a reference, so it will be never destroyed!
|
||||
std::shared_ptr<Dog> doggo_one (new Dog());
|
||||
std::shared_ptr<Dog> doggo_two (new Dog());
|
||||
std::shared_ptr<Dog> doggo_one(new Dog());
|
||||
std::shared_ptr<Dog> doggo_two(new Dog());
|
||||
doggo_one = doggo_two; // p1 references p2
|
||||
doggo_two = doggo_one; // p2 references p1
|
||||
|
||||
// As mentioned before there is a set of smart pointers. The way you have to
|
||||
// use it, is always the same.
|
||||
// This leads us to question, when to use which one?
|
||||
// std::unique_ptr - use it when you just want to hold one reference on
|
||||
// the same object.
|
||||
// std::shared_ptr - use it when you want to hold multiple references on the
|
||||
// same object and want to make sure that it´s de-allocated
|
||||
// when all refences are gone.
|
||||
// std::weak_ptr - use it when you want to hold multiple references from
|
||||
// different places for references for which it´s no problem
|
||||
// tp de-allocate.
|
||||
// There are several kinds of smart pointers.
|
||||
// The way you have to use them is always the same.
|
||||
// This leads us to the question: when should we use each kind of smart pointer?
|
||||
// std::unique_ptr - use it when you just want to hold one reference to
|
||||
// the object.
|
||||
// std::shared_ptr - use it when you want to hold multiple references to the
|
||||
// same object and want to make sure that it's deallocated
|
||||
// when all references are gone.
|
||||
// std::weak_ptr - use it when you want to access
|
||||
// the underlying object of a std::shared_ptr without causing that object to stay allocated.
|
||||
// Weak pointers are used to prevent circular referencing.
|
||||
|
||||
|
||||
/////////////////////
|
||||
|
Loading…
Reference in New Issue
Block a user