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[property_tree] Still no support for space
by Preston A. Elder 02 Sep '09

02 Sep '09

I noticed property_tree just got updated in the SVN repository. As per my previous email, RapidXML was upgraded from 1.0 -> 1.13. All well and good. This did fix problems with whitespace handling in previous versions - or more correctly, it split the functionality so it was controlled by 2 different flags. However, in addition to this, the flags passed to RapidXML have changed. Specifically, now the flags parse_normalize_whitespace and parse_trim_whitespace are both passed to RapidXML. And there is no way to disable this. In fact, there is no way to adjust space parsing at all in property_tree. The reason this is of concern to me is this. There is no way to get this to work: <field> <field> or <field>] <field> or <field> </field> None of which will output the space in the result. RapidXML doesn't parse an XSL file, nor does it understand xml:space. So even the following will not work: <field xml:space="preserve"> </field> or <field xml:space="preserve">] </field> In short, could you PLEASE adjust the RapidXML (which is still the default XML parser) options not to mangle the living heck out of all spaces, or provide the ability for the user to specify the behavior they want (like you do with comments). I should also mention that RapidXML defaults both parse_normalize_whitespace and parse_trim_whitespace to off. I did my own testing, adjusting the flags to RapidXML. If I leave parse_normalize_whitespace ON, but turning off parse_trim_whitespace, the <field> </field> and <field>] </field> examples above work. No adjustment either of these settings will make <field> </field> work. PreZ

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boost::regex Library crashes in MSVC8.0
by Naren Ramakrishnan 02 Sep '09

02 Sep '09

Hi, I am Boost novice and am trying to build a sample application from boost examples. The following is the environment details OS: Winxp sp2. Boost version : 1.40.0 Compiler / IDE : MSVC8.0/ Visual Studio 2005 I built the boost libraries using the above compiler using the bjam.exe tool and installed boost using the same tool(bjam.exe install). When I run the program(given below) by linking against libboost_regex-vc80-mt-1_39.lib with the following define flags(/D BOOST_REGEX_MATCH_EXTRA /D BOOST_REGEX_NO_LIB), I get a crash with the following message Unhandled exception at 0x00401e73 in BOOST TEST.exe: 0xC0000005: Access violation reading location 0x6c707849. Stack Trace is > BOOST TEST.exe!std::vector<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > >,std::allocator<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > > >::~vector<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > >,std::allocator<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > > >() Line 1088 C++ BOOST TEST.exe!std::vector<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > >,std::allocator<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > > >::_Destroy(boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > * _First=0x00383888, boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > * _Last=0x78138cd9) Line 1083 + 0x1d bytes C++ BOOST TEST.exe!std::vector<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > >,std::allocator<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > > >::~vector<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > >,std::allocator<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > > >() Line 1096 C++ BOOST TEST.exe!std::vector<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > >,std::allocator<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > > >::_Destroy(boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > * _First=0x00387c80, boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > * _Last=0x00387cbc) Line 1083 + 0x1d bytes C++ BOOST TEST.exe!boost::match_results<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> >,std::allocator<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > > >::~match_results<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> >,std::allocator<boost::sub_match<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > > > >() Line 81 + 0x83 bytes C++ BOOST TEST.exe!print_captures(const std::basic_string<char,std::char_traits<char>,std::allocator<char> > & regx={...}, const std::basic_string<char,std::char_traits<char>,std::allocator<char> > & text={...}) Line 44 + 0x22 bytes C++ BOOST TEST.exe!main(int __formal=, int __formal=) Line 48 + 0x3c bytes C++ BOOST TEST.exe!__tmainCRTStartup() Line 586 + 0x17 bytes C The program is #include "stdafx.h" #include <boost/regex.hpp> #include <iostream> using namespace boost; void print_captures(const std::string& regx, const std::string& text) { boost::regex e(regx); smatch what,w; std::cout << "Expression: \"" << regx.c_str() << "\"\n"; std::cout << "Text: \"" << text.c_str() << "\"\n"; if(boost::regex_search(text, what, e, boost::match_perl)) { unsigned i, j; std::cout << "** Match found **\n Sub-Expressions:\n"; for(i = 0; i < what.size(); ++i) std::cout << " $" << i << " = \"" << what[i].str().c_str() << "\"\n"; std::cout << " Captures:\n"; for(i = 0; i < what.size(); ++i) { std::cout << " $" << i << " = {"; j=0; for(j = 0; j < what.captures(i).size(); ++j) { if(j) std::cout << ", "; else std::cout << " "; std::cout << "\"" << what.captures(i)[j].str().c_str() << "\""; } std::cout << " }\n"; } } else { std::cout << "** No Match found **\n"; } } int main(int , char* []) { print_captures("Microsoft ", " Microsoft Internet Explorer"); print_captures("(.*)bar|(.*)bah", "abcbar"); print_captures("(.*)bar|(.*)bah", "abcbah"); print_captures("^(?:(\\w+)|(?>\\W+))*$", "now is the time for all good men to come to the aid of the party"); return 0; } However when I compile and run this program against boost libraries available in sourceforge under boost-binaries, it works fine. I am sure I am missing something. Could you please help me out Thanks Naren

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Boost.FileSystem talk from BoostCon now available
by Marshall Clow 01 Sep '09

01 Sep '09

at <http://blip.tv/file/2541291> More to come as I dig myself out..... -- Marshall

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[serialization] working around the pointer_conflict exception?
by T. Farago 01 Sep '09

01 Sep '09

I have implemented the serialise library of BOOST to my own classes. Using a single entry point it recursively goes through every member and saves the values. Of course initial implementation yielded the pointer_conflict expression as for example while going through objects A,B,C object A may have a pointer to B, and only afterwards is B actually saved. I tried - and thought - to fix this by using a two-phased approach. First I save all the actual objects from the entry point, secondly only the pointers. eg save_objects = true; ar & my_object; save_objects = false; ar & my_objects; and inside every class: class A { public: int a; int *b; serialise() { if (save_objects) { ar & a; } else { ar & b; } } }; This seemed sound but only during debugging did I realise that the second run of the serialiser doesn't do anything since my_object is already saved. So this won't work. Does anyone have better ideas on solving this problem, or has encountered and already solved this issue? -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

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Boost Polygon library Review
by Kai Benndorf 01 Sep '09

01 Sep '09

Dear developers, we are currently evaluating the boost polygon library as a possible replacement for our currently used package for polygon boolean operations. Because the review process is soon at an end i want to inform you of our experiences so far. For short, i vote for inclusion of the polygon lib into boost. We are evaluating it in the scope of an analysis tool out of the EDA field. One task in this tool is to determine overlays of copper planes on a pcb. For this we need the plane intersection functionality. We have integrated the boost polygon lib currently to use it in parallel to our old library. Up to now we have found no errors in the calculated plane intersections, and there are some quite complicated planes, with complicate holes on the test pcb. This is very promising and the results seem to be reliable. We used the library on Windows XP, MSVC 2008, only. No compilation problems occured. Double vs. integer coordinates. Our planes are described with double coordinates in mm. We convert them for the boost polygon lib to integer by multiplying them with a constant factor. A first try with an factor of 1e5 leaded to an error (overflow?). With a factor of 1e4 this error vanished. Our first approach was to use the polygon and polygon with hole classes provided by the library and copy our coordinates into them. It works, but the creation of the objects with the set( itBegin, itEnd) functions was really slow, especially for copying the holes into the polygon. Our current approach is with some own intermediate polygon and polygon with holes classes, which allocates the necessary memory on creation. This is a lot faster and is really usable. A third and still better approach would be to use the same polygon classes as in the rest of our application, but i postponed this for now. The performance seems to be slower than our old library, but this is not really evaluated yet, there can e.g. still be conversion penalties. The documentation was sufficient enough to integrate the library in our application, but surely can be better. Because i'm not experienced in such an extensive template usage as it is done in the polygon lib, i omit comments about the design of the library. But at least it proved, that it can really be used to work reliable on external polygon objects. Best regards Kai Benndorf

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windows timeout implementation
by Gennadiy Rozental 01 Sep '09

01 Sep '09

Hi, I have windows timeout support implemented for boost::execution monitor. It requires multithreading and thus introduces additional dependencies. I am thinking of making it available with compile time flag. Any comments/suggestions are welcome. Gennadiy

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[GSoC] Boost.Python py3k support project final report
by Haoyu Bai 01 Sep '09

01 Sep '09

Hi, As GSoC is officially finished, this is the final report of the Boost.Python py3k(Python 3) support project. The goal of this project is to provide seamless support for Python 2 and 3 in Boost.Python. So extension modules using Boost.Python can be easily migrated to Python 3. The SVN branch is located at: https://svn.boost.org/svn/boost/sandbox-branches/bhy/py3k/ Status ===== Currently, all the BPL test cases passed when running under Python 3, and there are almost no change for most of the test cases. To support the Python 3 unicode string, some of the default converts between PyString and C/C++ strings are changed to convert between PyUnicode and C/C++ strings. Support for py3k in Boost.Build is done. Also, a piece of document is written in the "News" part of BPL document. API Changes ========== There are some minor API changes: 1) Introduced object.contains where x.contains(y) is equivalent to Python code y in x. Now dict.has_key is just a wrapper of object.contains. 2) When building against Python 3, str.decode will be removed. 3) When building against Python 3, the original signature of list.sort, which is: void sort(object_cref cmpfunc); will change to: void sort(args_proxy const &args, kwds_proxy const &kwds); This is because in Python 3 list.sort requires all its arguments be keyword argument. So you should call it like this: x.sort(*tuple(), **dict(make_tuple(make_tuple("reverse", true)))); // This is equivalent to the Python call x.sort(reverse=true) 4) When building Boost.Python against Python older than 2.6, the following macros will be defined in Boost.Python header: # define Py_TYPE(o) (((PyObject*)(o))->ob_type) # define Py_REFCNT(o) (((PyObject*)(o))->ob_refcnt) # define Py_SIZE(o) (((PyVarObject*)(o))->ob_size) These are macros defined in Python >=2.6 header. We defined for Python < 2.6 so when you are using Boost.Python, these macros will be always available. Please refer to PEP 3123 (http://www.python.org/dev/peps/pep-3123/) for details about these macro. Building and Testing =============== To build Boost.Python with Python 3, first write your user-config.jam contains these line: using python : 2.6 ; using python : 3.2 ; where the "2.6" and "3.2" should be replaced by the actual version of Python 2 and Python 3 on your system, respectively. Then call "bjam", it will build out a "libboost_python.so" and a "libboost_python3.so". The latter one is the Boost.Python library built against Python 3. To run test cases against Python 3, what you need to do is to switch into the libs/python/test, then run: bjam python=3.2 It will automatically call the "2to3" tool to convert the Python source code in test case to Python 3 syntax. So we only need to maintain the test cases in Python 2. Further Works =========== I'm going to merge the py3k branch back to trunk. After the merge, more tests can be done to check is there any regression, also some people may want to start to use it to make your projects run on Python 3. Then I can get some bug report and feedback, thus more improvement is expected. Thanks! -- Haoyu BAI School of Computing, National University of Singapore.

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[polygon] examplefile compilation failed
by Joachim Faulhaber 31 Aug '09

31 Aug '09

Hi Luke and polygonists! I had problems compiling the example files from the doc's main page with msvc-9. None of custom_p*.cpp examples compiled. Also the connectivity_extraction_usage.cpp example failed. (1) connectivity_extraction_usage.cpp: #include <boost/gtl/gtl.hpp> must be replaced by #include <boost/polygon/polygon.hpp> namespace gtl = boost::polygon; has to be added. (2) custom_point.cpp: compilation yields: 1>.\custom_point.cpp(75) : error C2757: 'gtl' : a symbol with this name already exists and therefore this name cannot be used as a namespace name 1>.\custom_point.cpp(77) : error C2143: syntax error : missing ';' before '<' 1>.\custom_point.cpp(77) : error C2913: explicit specialization; '::geometry_concept' is not a specialization of a class template and many errors more after replacing gtl:: by boost::polygon:: and namespace gtl { ... } by namespace boost { namespce polygon { ... } } and adding typedef int coordinate_type; to struct CPoint the code finally compiled. Are these examples intended to be excercises ;) HTH Joachim

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C++ MapReduce performance - compared to C Phoenix
by Jose 31 Aug '09

31 Aug '09

I wanted to share some performance numbers to encourage others to write examples or applications using the C++ multi-core mapreduce library being developed by Craig H. I ran some tests comparing the C++ version to the C version, for the word_count example. The tests are run on a X86_64 linux Fedora 10 with 2 cores. The results below show that the C++ MapReduce (mr) has very similar performance to the C version (mr-c). The tests start running phoenix first. Run 3 and 4 show that c++ mr is slightly faster. When using 1MB MR_L1CACHESIZE (which should be the best comparison) shows that mr-c is a little bit faster but not much. 1-mr-c 0m18.077s 2-mr 0m13.818s 3-mr-c 0m14.828s 4-mr 0m14.148s 5-mr-c-1MB 0m14.006s 6-mr-c-2MB 0m14.084s Note: The C++ version uses a chunk size of 1MB while the C version uses by default a chunk size of 64KB (which can be changed with the variable MR_L1CACHESIZE) regards jose

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Boost.MapReduce: what next?
by Craig Henderson 31 Aug '09

31 Aug '09

I am thinking now about how to progress my MapReduce library that is in the Boost SandBox. I have completed the single-machine implementation; it's performance is comparable to other libraries such as Phoenix (http://mapreduce.stanford.edu) and has been tested by a few people on this list. There has, however, been little interest in the library so far from Boost users/developers which surprises me. I don't know if that is because of the single-machine limitation and people don't see any value that MR can bring to multi-threaded programming? So where do I go next with the library? Options that I see are: 1. Complete the documentation and submit the current library to Boost for a formal review. I'm not clear there is sufficient interest, though. 2. Continue to develop the library in the sandbox to multi-machine implementation and work towards submitting that for formal review. Is there interest for this? 3. Accept that Boost is not an appropriate forum for a MapReduce library and find an alternative community to develop the library. Looking at the download figures from the Vault, there has been a reasonable number of downloads; Of course there is no way to tell the number of people looking at the sandbox implementation. Perhaps the library has some silent interest? Please let me know your thoughts. Thanks -- Craig Craig Henderson <http://craighenderson.co.uk/> http://www.craighenderson.co.uk http://www.siteupdatenotification.com

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