I have corrected several errors ( thanks to the people who sent me comment, suggestions and bugs). The lock mechanism ( 1 Writer / N Readers) have been redesigned in order to correct previous errors and increment the speed. The actual version is built over spinlocks and yield functions. It provide an alternative to the upgrade mutex. You have a detailed description with diagrams and examples in https://dl.dropboxusercontent.com/u/8437476/works/countertree_2.0/doc/single... *LIBRARY DESCRIPTION* This library provide a concurrent and thread safe implementation of the *tree based data structures* (set, multiset, map and multimap, plus a unordered tree named vector_tree) with *random access iterators* and *access by position like a vector*. This permit to *distribute the elements* stored in the trees, between an *arbitrary number of threads*, identically as do with the vectors. Over it you can use many algorithms designed for vectors ( as quicksort over an unsorted tree) and *making easy the design of parallel algorithms* applied to the tree based data structures , and their use by the multicore development tools.. [image: Imágenes integradas 1] These data structures are based on a kind of augmented red-black trees, where each node have a counter with with the number of nodes under which permit the access by position, like in a vector, to the elements stored in the tree, and random access iterators. I named this tree of counters *countertree* Until now, in many practical problems, the binary trees was not used , by the difficult for to distribute the elements stored between an arbitrary number of cores, and the difficult for to develop parallel algorithms. This limitation force to use only 1 thread with these data structures. And with big problems, usually it is not a good solution. With the countertrees, perhaps it would be interested reevaluate some algorithms, and make an comparison between the present algorithms and the possible options, in order to see the performance, the memory used and the flexibility. If you are interested, you have a brief document ( 2 pages) about the manycore strategies<https://dl.dropboxusercontent.com/u/8437476/works/doc/Manycore_Strategies.pdf>with this library, and other brief project description<https://dl.dropboxusercontent.com/u/8437476/works/doc/Brief_project_description.pdf>(2 pages) where provide a global vision of the project and their parts. I think is a good starting point in order to examine the library. *You can find the code and the documentation in my web pages in dropbox* *https://dl.dropboxusercontent.com/u/8437476/works/countertree_2.0/index.html <https://dl.dropboxusercontent.com/u/8437476/works/countertree_2.0/index.html>* *or if you prefer in a git format* *https://github.com/fjtapia/countertree_2.0 <https://github.com/fjtapia/countertree_2.0>* Please, if you have any idea , any comment or see any fail, any lack, please say me in order to improve the library, and provide between all ,a fast, robust and reliable tool to the C++ programmers. If you want more information, need something, please, say me, and I will try to do. Thanks by your interest. Yours Francisco Jose Tapia e-mail : fjtapia@gmail.com