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[gsoc] PLEASE SUBMIT PROPOSALS NOW
by troy d. straszheim 01 Apr '09

01 Apr '09

Hi Students, This just in from the director of the GSOC, in an email with lots of asterisks and capital letters in the subject: > I realize that many organizations are working with students to refine > their proposal ideas on their mailing lists, wikis, etc. However, a > proposal on a wiki, mailing list, etc. does not constitute an actual > application for the program; the proposal must be submitted to the > GSoC 2009 site. While doing review and refinement outside of > http://socghop.appspot.com is a useful exercise, it doesn't allow us > to accurately gauge the number of student proposals we're receiving > for GSoC 2009. > > Please help us get an accurate sense of how many proposals will be > submitted for GSoC 2009 by asking your students to submit their > proposals to the GSoC 2009 site *now*. They are welcome to link to the > wiki page, mailing list thread, forum topic, etc. where their > proposals are under discussion and refinement as part of the proposal > submission process.[0] And the [0] refers to: http://socghop.appspot.com/document/show/program/google/gsoc2009/userguide#… Many of you have done a *great* job raising proposals, discussing and refining them. Please get some placeholder applications up asap, even if they aren't completely finished. I'm looking forward to seeing yet more good discussion and refinement of your proposals. Everybody keep up the good work. On behalf of the boost community, thanks for your enthusiasm. :) -t

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How to generate a Bernuolli number
by Barco You 01 Apr '09

01 Apr '09

Hi, I want to randomly generate a Bernuolli number [0, 1],with probability p ~[0 1]. How to do that with boost? Thanks! -- ------------------------------- Enjoy life! Barco You

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[GSoC] Opinions and suggestions for improving CGI library
by Eugene Wee 31 Mar '09

31 Mar '09

Hi everyone, I hope to participate in this year's Google Summer of Code by working on a project for Boost, and would like to get opinions and suggestions on what I intend to do. In GSoC 2007, Darren Garvey worked on a CGI library under the mentorship of Christopher Kohlhoff. This sounded interesting to me, as my first forays into programming were for the Web with PHP, but I never actually used CGI with C++, even though I have been aware of cgicc and Wt for some time. I contacted Darren, who informed me that while he was still working on the library, he lacked the time to implement many features, and would welcome help. There were a number of features that he highlighted, but three of them stood out for me: * Persistent sessions >From my experience with PHP, session handling tends to be a heavily used feature that this CGI library lacks. I intend to design an interface for session handling that would allow the use of memory mapped files (with the help of Boost.Interprocess) and relational databases as storage options. I will also implement session handling with one of the possible storage options. * Improved multipart/form-data parsing Currently, the parsing is done with regex, which is something of a hack in this case. The aim is to replace the use of regex with the use of Boost.Spirit. From what I see, this is also an area that needs more testing, hence developing the test suite would be an important part of this subproject. * Windows support for Fast CGI Portability is one of the goals of Boost, and this is of interest to me personally as I use Windows quite often. However, I am unable to conceive a solution (or even pinpoint the problem) to this right now, but I believe that with time I can figure it out, especially since Darren has some idea as to what might need to be done. For reference: Darren's proposal abstract: http://code.google.com/soc/2007/boost/appinfo.html?csaid=5869D5120647336D Current documentation: http://omnisplat.com/docs/ In Boost sandbox: https://svn.boost.org/svn/boost/sandbox/SOC/2007/cgi/ Thank you, Eugene Wee

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How to bind objects with reference handle
by Altaf Navalur 31 Mar '09

31 Mar '09

Hello All, I am using the latest version of boost. I am trying to bind a particular member function to a signal. I am trying to bind the signal to a pointer, which is a reference Handle(WeakRefHandle,RefHandle). I am getting an error for this. How do I fix it. I am trying to port a game, So switching to boost::shared_ptr is not an option, as it will force lot of changes in the game code. Cheers, Altaf -- An eye for an eye only ends up making the whole world blind.

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Google SoC idea - Relations
by Michael Lopez 31 Mar '09

31 Mar '09

Hello everyone. I am an undergraduate student of Kent State University and I am drafting a proposal for GSoC to try and extend the BGL. I don't exactly know to whom I should direct this post, but I wanted to informally pass this idea to the boost community. I would like to add a binary relation data type to the BGL. Binary relations are quite similar to graphs and can be visualized using directed graphs. I would even like to use the graph interface for relations, since one of its key features should be that a user can use relations just as she would use graphs. Sometimes, a single criterion is all that is needed to define a relation (an edge) between two objects (vertices). This relation can be a '<' operator or '>=' operator or something more complex, for instance an equivalence relation between some geometric shapes. It doesn't really matter. The beauty in this datatype is that the relation, in the form of a function, will be user defined. I would like to provide several common relations such as less than and modular equivalence, but the relation is completely up to the user and packed snugly into a familiar interface that is quite capable of handling relations. Speaking of snug packing, the other key feature that differentiates relations from graphs is data storage. The relation data type will store a set of objects rather than vertices and edges. Since the relation is defined as a function, checking to see whether there is a relation (an edge) between two objects (vertices) simply requires a function call with those two objects as parameters. This bypasses the look up of an edge in favor of a computation. The computation, however, does not have to be limited to a boolean value. In the case of weighted complete graphs, the relation can be utilized as a normal functions, such as distances between cities. Better yet, the Boost.optional can be used to return either a type or false if a relation does not exist. Time permitting, I would also like to examine the possibility of providing support for properties like transitivity and symmetry and also provide a data type that would enable closures, such as transitivity (connectivity). who am I: Like I mentioned above, I am a KSU student majoring in both mathematics and computer science. I've been programming in c++ since early highschool. good heavens, that would be about 8 years. I am fascinated by generic and template programming and enjoy applications of math in programming, particularly visulaization and applications of discrete math. thank you for reading, michael lopez

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[mirror] -- RFC
by Matus Chochlik 31 Mar '09

31 Mar '09

Dear Boosters, The Mirror library has been around for nearly a year. I would like to start doing the preparations for getting the library ready for a formal review and before that I would like to hear your opinions on whether this library actually belongs to Boost and any suggestions on how to improve it or what to change. For those of you who are not familiar with it, Mirror is a compile-time reflection facility with some run-time features. The sources can be downloaded from the Vault or checked out from the Sandbox (http://svn.boost.org/svn/boost/sandbox/mirror/) Since the docs (http://tinyurl.com/atba2k) do not cover everything yet, you can see the usage of several of the implemented but undocumented features in the test suite and in the examples (http://tinyurl.com/c4xygh) Some people have found the Concept browser (http://tinyurl.com/czz3t2) to be a good starting point and a useful quick reference. It, however, requires a XSLT capable web browser. It is known to work with MSIE 7+ and Firefox 3.x.y without the need to install any other software. Best regards, ________________ ::matus_chochlik

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[thread] Error: cannot open file 'libboost_thread-vc90-mt-gd-1_38.lib'
by Santosh Naidu 31 Mar '09

31 Mar '09

Hi All, I am new to Boost. I am getting the following error when I try to include <boost/thread/condition_variable.hpp> Error 1 fatal error LNK1104: cannot open file 'libboost_thread-vc90-mt-gd-1_38.lib' I have followed all the steps to setup the boost library given in the startup document. Regards, Santosh

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[thread] Assertion failed get_system_time_sentinel()
by Filip Klasson 31 Mar '09

31 Mar '09

Hi, I get Assertion failed timed_lock(::boost::detail::get_system_time_sentinel()), file c:\boost\thread\win32\basic_timed_mutex.hpp, line 64. Code in basic_timed_mutex.hpp: void lock() { BOOST_VERIFY(timed_lock(::boost::detail::get_system_time_sentinel())); //Line 64 } Code in thread_time.hpp: namespace boost { ... namespace detail { inline system_time get_system_time_sentinel() { return system_time(boost::posix_time::pos_infin); } ... } } I read in a previous thread that this was a known bug that is fixed in Boost 1.38 but i am using Boost 1.38. Is this another bug or is it not fixed? This only happends sometimes and it happends when i call wait on a condition variable. Here is my code, i have marked where Assertion failed happends. boost::mutex::scoped_lock lock(_mutex); while(_queue.empty()) { _condition.wait(lock); } //Assertion failed happends here. //Another thread is signaling the condition variable when an element is added to the _queue. I am happy with all sorts of helpful comments. Best regards

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[iostreams] binary memory stream
by Kenny Riddile 31 Mar '09

31 Mar '09

I'm still pretty inexperienced with the iostreams library, so this may be a simple question. I'm trying to use GIL to write a PNG to a memory stream instead of a file stream. The write_view() function in the new version of GIL's io extension expects an ostream opened in binary mode as it's first parameter, such as: using namespace std; using namespace boost::gil; ofstream outputStream( "foo.png", ios::out | ios::binary ); write_view( outputStream, const_view(image), png_tag() ); I'm attempting to write to memory instead of a file, by doing this: using namespace boost::gil; using namespace boost::iostreams; typedef stream< back_insert_device< std::vector<char> > > BufferStream; std::vector<char> buffer; BufferStream bufferStream( buffer ); write_view( bufferStream, const_view(image), png_tag() ); The data that ends up in buffer is identical to the data that ends up in foo.png from the first example if I don't open outputStream in binary mode. So how can I make a binary memory stream with the iostreams library? Do I need to write my own filter?

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Re: [boost] unicode tools and an unicode string type
by Graham 30 Mar '09

30 Mar '09

8. Re: [gsoc] unicode tools and an unicode string type (Mathias Gaunard) >It's really aimed at being simple and non-intrusive. Components are >fairly separate and code is thus incremental, and the unicode string >just composes the work. > >I personally believe basic_string, char_traits, and codecvt facets and >the standard locale system are not really suitable to deal with unicode, >which may have been the reason why previous proposals ended up they way >they did. >I think some people said the same in the various unicode discussions, too. >Efficient algorithms are provided by the Unicode consortium, so it's >mostly just the design or glue code that needs work. >The glue depending on what integration with other components is being >done. Here, it's mostly just range concepts. Mathias, Unfortunately the simple algorithms supplied by the Unicode consortium all end up requiring a character traits tables ! There are large tables that need to be transformed into compact sets of traits and this was done by myself and Rogier. These traits are then used to drive simple [ish] rules. So whatever you do - you need to start with the character traits tables [which are large]. Yours, Graham Barnett

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