July 2008 - Boost - lists.boost.org

boost-style mutable heap
by Tim Blechmann 03 Jul '08

03 Jul '08

hi all, i am curious, is there any attempt to implement mutable priority queues as a boost-style library ... i am familiar with dietmar kuehl's heap implementations, which have never been reviewed nor integrated in boost ... is anyone working on / interested in a mutable priority queue implementation, maybe as part of boost.intrusive? thanks, tim -- tim(a)klingt.org http://tim.klingt.org Question: Then what is the purpose of this "experimental" music? Answer: No purposes. Sounds. John Cage

3 2

A branching/tagging idea for releases
by Daryle Walker 03 Jul '08

03 Jul '08

Here's an idea on how we can manage our source-control for releases: 1. When we're ready to start a new release, make a branch from the trunk with a name like release_1_??_x (e.g. "release_1_37_x") 2. Finalize what needs to be done to make that branch ship-worthy 3. Make a tag from that branch with a name like release_1_??_0 (e.g. "release_1_37_0") 4. Export that tag to a fresh directory and create the appropriate archive file to upload to SourceForge, etc. (The directory shouldn't have any source-control debris in it. Maybe this needs to be done once on each platform to ensure the best archive format and the proper line-ending markers.) 5. If bug-fixes for that release need to be done, continue to use the release_1_??_x branch (and merge the fixes back to the trunk, or vice versa) 6. Make a new tag named like release_1_??_1 and ship it as in [4] for any bug-fix releases (increase the number for subsequent bug- fixes published) 7. New stuff and substantial changes go on the trunk; publish those by going back to [1] with a release_1_(??+1)_x branch -- Daryle Walker Mac, Internet, and Video Game Junkie darylew AT hotmail DOT com

6 14

Documentation for Boost libraries
by Edward Diener 03 Jul '08

03 Jul '08

In general Boost has many libraries with good to absolutely first class documentation. Among the many Boost libraries I have used, all with good documentation, are regex, iostreams, function, bind, optional, signals. tribool, tokenizer, and spirit, but of course there are many other libraries with great documentation in Boost. One of my prerequisites for a library with good documentation is that some sort of overview must be given for the functionality of the library so that the end user knows what is available, and what each available part of the library generally entails. For me this overview must be written out and not just given as a series of programming examples, whether in the form of tutorial code, example code, or whatever one wants to call explanations of functionality based almost purely on some hypothetical program or mini-program. In this I may be different from many programmers but I just find it very hard to understand library functionality from example code without basic generalized explanations of functionality. Today, looking for a socket library to use in my C++ code I decided to look at the documentation for ASIO. I was shocked to find out that there is no overview of the functionality of this library at all, but just a series of tutorials and examples and then a reference listing a multitude of classes. I do not believe this is adequate for explaining library functionality and puts a totally unnecessary burden of the end-user when learning the functionality of a library. I would like to encourage Boost developers to always give an overview of the functionality of their library and its general concepts and classes, as almost all libraries currently do. While I am appreciative of tutorials and exmaples as an extra learning device, I do not believe that library documentation should exist with some sort of overview, as mentioned above. I have written this because I am disturbed that ASIO was accepted with the sort of documentation which has been created for it. I do not think such a way of presenting a library is adequate for an organization like Boost whose overall excellence is acknowledged throughout the C++ community.

6 12

[shifted_ptr] STL required modifications
by Phil Bouchard 03 Jul '08

03 Jul '08

Ok, If we comment out line 68 of shifted_ptr_test2.cpp in the sandbox and uncomment line 69 we will get a simplified version of the error messages we used to have with std::vector. It is easier this way uncovering the required modifications necessary to make STL user-friendly with smart pointers. I have also made shifted_allocator the way it should be. Yes it is strange replacing pointers to nodes inside containers and I don't see an urgent need for it but this can help unobfusticating the standards regarding pointers to nodes. Thanks, -Phil

1 0

Interest in HeapAware mixin?
by Corey Goldfeder 03 Jul '08

03 Jul '08

Hi everyone, Would there be any interest in a mixin class that signs an object as being on the stack or the heap? Any class that needs to know if it can delete 'this' can (possibly multiply) inherit from class HeapAware, and will gain a member function on_heap() that returns whether the object was dynamically allocated. A similar idea is discussed in More Effective C++, item 27, but unlike that approach, my implementation works correctly for arrays. It also does all the work during construction, so that checking on_heap() just returns a preset bool. The extra cost at construction is a small constant. It is not yet thread safe, but could be made so reasonably easily. Unlike some similar classes, it uses nothing compiler specific, even for arrays, which is where people usually need to "cheat". In particular, for arrays it makes no assumptions about where in the allocated memory the objects are constructed, and so alignment issues or extra compiler bookkeeping don't cause any problems. I currently use this class within a 3d mesh library I maintain. I have triangles that belong to multiple meshes, and I want updates to a triangle to be noticed by all meshes that contain it, so that they can mark their cached mesh statistics as being out of date. This means I need an event listener mechanism. I also want triangles ownership to be shared among the meshes, so that deleting a mesh deletes any triangles that no other mesh currently contains. I built a two way smart pointer / event listener class that maintains a single list that serves as both listeners and owners. The HeapAware class that I am proposing for Boost was invaluable to me, because it allowed me to disable self deletion for triangles on the stack. The snippet below demonstrates how HeapAware can be used. (Obviously this a trivial example). My implementation produces the correct output for all these cases, as well as for globals, statics, and objects created with placement new and placement new[]. It also works correctly with copy construction, which some other implementations fail at. class Widget : public HeapAware {}; int main() { Widget stack_w; Widget* heap_w = new Widget; Widget stack_copy(*heap_w); Widget* heap_copy = new Widget(stack_w); Widget stack_array_w[2]; Widget* heap_array_w = new Widget[2]; printf("Stack Widget: %d\n", stack_w.on_heap()); printf("Heap Widget: %d\n", heap_w->on_heap()); printf("Stack copy of Heap widget: %d\n", stack_copy.on_heap()); printf("Heap copy of Stack widget: %d\n", heap_copy->on_heap()); printf("Stack array widget 0: %d\n", stack_array_w[0].on_heap()); printf("Stack array widget 1: %d\n", stack_array_w[1].on_heap()); printf("Heap array widget 0: %d\n", heap_array_w[0].on_heap()); printf("Heap array widget 1: %d\n", heap_array_w[1].on_heap()); return 0; } Thanks! -Corey Goldfeder

1 0

Exception lib documentation
by Emil Dotchevski 03 Jul '08

03 Jul '08

I have a question about the release procedure, do I need to do anything special to hook the Exception library documentation into the main Boost documentation? (The main Boost Exception documentation file is libs/exception/doc/boost-exception.html) Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

3 5

[release][website] Adding 1.36 to the beta site and checklist additions
by Daniel James 02 Jul '08

02 Jul '08

Hi, I've just created a placeholder for the new release information in the beta site. I hope I'm not jumping the gun there. Also, I've added a few items to the release manager checklist which need to be done for the website. These tasks probably should be delegated but I thought they were worth including in the main checklist. Also, would it be possible to upload (or download for that matter) the release snapshots to the beta site? So we can see how well the new documentation works in the site before it is released. thanks, Daniel

1 0

Is "+" safe for file names?
by Rene Rivera 02 Jul '08

02 Jul '08

Just noticed this directory name: libs/filesystem/test/vc++.boost.filesystem Is "+" safe to use across file systems? Hm, actually I'm fairly sure more than one "." is not safe. For example in the MVS systems? -- -- Grafik - Don't Assume Anything -- Redshift Software, Inc. - http://redshift-software.com -- rrivera/acm.org (msn) - grafik/redshift-software.com -- 102708583/icq - grafikrobot/aim,yahoo,skype,efnet,gmail

7 11

Where can I find Phoenix 2.0?
by Mathias Gaunard 02 Jul '08

02 Jul '08

I discovered Phoenix 2.0 which looks fairly great according to the documention, however I can't find it anywhere. Is it what's in trunk/final/boost/spirit/phoenix/ on the spirit svn?

2 1

[circular_buffer] will release branch be updated with fixes from trunk?
by Thorsten Ottosen 02 Jul '08

02 Jul '08

Hi Jan, The old behavior of the default constructor is causing my release regressions to break. I'm sure the new behavior (not doing any allocation) will be most welcome in the release branch for other reasons as well. Do you plan on changing this in the release branch? best regards -Thorsten

1 0