Skip to main content

Boost - shared pointer

Shared pointer is another kind of Boost library's pointer. It is similar to scoped pointer but shared pointer allows share ownership of object. We are able to assign two or more pointers pointing to the same object (it was impossible for scoped pointer).

Take a look to the example below: Output of this example is:
In point I we are initializing two shared pointers pointing to two separate instances of TestClass class, then we are printing its values in point II.

Point III shows use difference between shared pointer and scoped pointer. We are assigning two pointers to the same object of class TestClass. In this point object having testValue==5 is being destroyed (because we remove the only one pointer to that object). Also, we have two pointers pointing to objects having testValue==6 now. Note that that object will be destroyed when last shared pointer pointing to them will be destroyed (int our case it is destroyed when we are reaching end of main() function). This is key difference between scoped pointer and shared pointer.

In point IV we are printing testValues of objects which are being pointed by our both scoped pointers. Actually, it is the same object so we are getting value 6 in both cases.

Code of this example you can find in our GitHub account:
https://github.com/xmementoit/CppAdventureExamples/tree/master/boost/sharedPointer


Labels:

Comments

  1. blogReader19 January 2014 at 18:42

    Are you going to present some article describing comparison (similarities and differences) of all Boost smart pointers?

    ReplyDelete
  2. Unknown19 January 2014 at 18:43

    I scheduled your request in my articles lists so it will be released here, soon.

    ReplyDelete

Post a Comment

Popular posts from this blog

GDB Automatic Deadlock Detector

Have you ever had a problem with detection deadlock between threads in your C/C++ application? Would you like to do that automatically? Try this GDB Automatic Deadlock Detector from my github: GDB Automatic Deadlock Detector Picture source: http://csunplugged.org/wp-content/uploads/2015/03/deadlock.jpg1286488735
Post a Comment
Read more

C++ Multithreading - Race conditions

In the previous C++ Multithreading article I presented you how to pass parameters between threads. Take a detail look on the output of that example once again: In the first line of that output you can notice that output text from two threads is mixed. You are probably wondering why it happens? It is because we are not protecting resources which are shared by two threads (in this example cout stream is shared in both threads) which causes multithreading's phenomenon called race condition . Because threads switching and accessing to shared resources are managed by operating system we do not know when std::cout stream will be accessed by main thread and when it will be accessed by second thread. Therefore in the previous article I mentioned that output of the example can be little different on your computer than my output example. What's more it is possible that this output will be different for few consecutive invoking of the example on the same machine. It is beca...
Post a Comment
Read more

Blog's new layout

As you noticed this blog has new layout from today. I hope you like it. I think new layout looks better and more modern than previous one. Please, write you opinion about new layout in comments. If you have some ideas how to make this blog better, all ideas are welcomed. Enjoy new layout and blog articles.
3 comments
Read more