(C++) std::shared_ptr

 

 

std::shared_ptr is a type of smart pointer that can be copied safely and cheap, without copying the object pointed to. When the last std::shared_ptr using an object goes out of scope, it will delete the object pointedto.

 

 

 

 

 

 

Creating a std::shared_ptr

 

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#include <memory> int main() {   //Only works when using C++11   std::shared_ptr<int> p; }

 

 

 

 

 

Advice

 

• Prefer pass-by-reference-to-const to pass-by-value for std::shared_ptrs [1]
• Use to refer to sharedobjects [2]
• Prefer std::unique_ptr over std::shared_ptr [3]

 

 

 

 

 

References

 

1. Scott Meyers. C++ And Beyond 2012 session: 'Initial thoughts on Effective C++11'. 2012. 'Prefer Pass-by-Reference-to-const to Pass-by-Value for std::shared_ptrs'
2. Bjarne Stroustrup. A tour of C++. 2014. ISBN: 978-0-321-958310. Chapter 11.7.6, page 131: 'Use shared_ptr to refer to shared objects'
3. Bjarne Stroustrup. A tour of C++. 2014. ISBN: 978-0-321-958310. Chapter 11.7.8, page 131: 'Prefer unique_ptr over shared_ptr'

 

 

 

 

 

External links

 

• GCC's page about std::shared_ptr
• Boost's page about boost::shared_ptr