June 2008 - Boost-users - lists.preview.boost.org

Re: [Boost-users] serialization, 1.34/1.35 difference: serializing a vector
by Filip Peters 03 Jun '08

03 Jun '08

----- Original Message ---- From: "Pfligersdorffer, Christian" <Christian.Pfligersdorffer(a)eos.info> To: boost-users(a)lists.boost.org Sent: Friday, April 4, 2008 6:30:00 AM Subject: Re: [Boost-users] serialization, 1.34/1.35 difference: serializing a vector Hello everybody, we at EOS too rely heavily on backwards compatibility of boost::serialization so I read this topic with great interest. And found Filip's discovery quite shocking I must say! I tried the testing program on my machine using boost-1.33.1 and boost-1.35 and all of the boost::archives. And guess what: It worked!! Soooo, this is quite confusing! Either version 1.34 breaks the compatibility or Filip's observation is wrong. Or mine, as everything might depend on the machine architecture or some other nasty detail... Is think this has to be investigated closer. Very interesting. I dug up the zip file for 1.33.1 and ran a couple of tests. (mostly to prove myself that I'm not seeing ghosts.) result: from 1.33.1 to 1.34: no problem from 1.33.1 to 1.35: no problem from 1.34.1 to 1.35: problem. problem seems to be a new "optimization" in the vector serializing. I normally use the binary files, but for debugging purposes the xml output is fantastic. It shows exactly why it works/doesn't work. xml from 1.33.1: <?xml version="1.0" encoding="UTF-8" standalone="yes" ?> <!DOCTYPE boost_serialization> <boost_serialization signature="serialization::archive" version="3"> <vectorToSave> <count>2</count> <item>0</item> <item>1</item> </vectorToSave> </boost_serialization> xml from 1.34.1: <?xml version="1.0" encoding="UTF-8" standalone="yes" ?> <!DOCTYPE boost_serialization> <boost_serialization signature="serialization::archive" version="4"> <vectorToSave> <count>2</count> <item_version>0</item_version> <item>0</item> <item>1</item> </vectorToSave> </boost_serialization> xml from 1.35: <?xml version="1.0" encoding="UTF-8" standalone="yes" ?> <!DOCTYPE boost_serialization> <boost_serialization signature="serialization::archive" version="4"> <vectorToSave> <count>2</count> <item>0</item> <item>1</item> </vectorToSave> </boost_serialization> As you can clearly see, from 1.34.1 to 1.35, the archive version stayed at 4, while item_version went missing in 1.35. Btw: my portable binary archive which really does nothing more than endian handling on top of the binary archive was broken by version 1.34 too (wrt reading files generated by 1.33.1). It has to do with the serialization of std collections as well, that much I found out. I did not do extensive investigation then but simply did not migrate. I may have time to take a closer look in the near future though. Regards, -- Christian Pfligersdorffer Software Engineering http://www.eos.info PS: Jens wrote: > Have you reported these issues? Please remember that once you > start testing development versions, especially release > snapshots, you could ensure that such issues are fixed before the > release! Never forget that there users who are not so involved in the boost community, be it for the lack of interest or simply because they are engaged in projects that leave no room for testing of upcoming library versions. Between the announcement and the official release there was less than a laughable day... Exactly. I didn't check the boost list in the previous two weeks (busy with an internal release myself), so wasn't really aware that there was rc2 and rc3.(heck, was rc1 even announced on the users list?) Monday I checked and saw that the boost website was updated, and a nice new version. When I got everything to compile, I noticed that I couldn't read in some older files. So I made a sample program, and reported the output. I also opened a trac ticket for this. Filip Peters. ____________________________________________________________________________________ You rock. That's why Blockbuster's offering you one month of Blockbuster Total Access, No Cost. http://tc.deals.yahoo.com/tc/blockbuster/text5.com

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Re: [Boost-users] boost & c-style calback issue
by Anders Dalvander 02 Jun '08

02 Jun '08

> > Your approach is exactly what we don't want, since it makes it an object-based > based solution rather than instance-based. > We are using a functor (therefor the oprerator()) so that the solution remains > instance-based. > Is your application threaded? If so couldn't you use thread_specific_ptr for emulating a instance-based functor? class A; class B; class C { public: C() { instance().push_back(this); } ~C() { instance().pop_back(); } int operator()(A* a, B* b) { // Do your stuff. } static int wrapper(A* a, B* b) { return instance().back()->operator()(a, b); } private: C(const C& rhs); C& operator=(const C& rhs); static this_vector& instance() { this_vector* t = ptr.get(); if (!t) { t = new this_vector(); ptr.reset(t); } return *t; } typedef std::vector<C*> this_vector; static boost::thread_specific_ptr<this_vector> ptr; }; typedef int (*foobar)(A*,B*); void do_something(foobar cb); C obj; do_something(C::wrapper); Regards, Anders

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Parsing URI's using boost regex
by Reena Dass 02 Jun '08

02 Jun '08

I'm trying to write a parser for URIs. I tried the grammar straight from RFC 2396 boost::regex parser("^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))?", boost::regex::perl|boost::regex::icase); This does not work since it I get an exception due to invalid regular expression. I found another regular expression, which does not throw an exception but does not give me the parts of the URI using boost::match_result boost::regex parser("(([a-zA-Z][0-9a-zA-Z+\\-\\.]*:)?/{0,2}[0-9a-zA-Z;/?:@&=+$\\.\\-_ !~*'()%]+)?/{0,1}([0-9a-zA-Z;/?:@&=+$\\.\\-_!~*'()%]+)?(#[0-9a-zA-Z;/?:@ &=+$\\.\\-_!~*'()%]+)?", boost::regex::perl|boost::regex::icase); What am I doing wrong here? Reena

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Is there any class that can promote a type to the complex type?
by Peng Yu 02 Jun '08

02 Jun '08

Hi, To promote a type, no matter complex or not, to the complex type can be done by the following code. RET would give me a complex type. The code is simple. I'm wonder if boost has already supplied such facility so that I don't have to include the following snippet in my own code. Thanks, Peng #include <complex> #include <iostream> template <typename T> struct convert { typedef std::complex<T> RET; }; template <typename T> struct convert<std::complex<T> > { typedef std::complex<T> RET; }; int main() { std::cout << convert<double>::RET() << std::endl; std::cout << convert<std::complex<double> >::RET() << std::endl; }

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[boost.function] evaluating needed arguments only
by Olaf Krzikalla 02 Jun '08

02 Jun '08

Hi, is it possible to check a function bound to boost::function, if a particular argument is actually needed? Example: ---- struct bar {}; typedef boost::function<void(int, bar&)> tSlot; void foo(tSlot& s); void barNeeded(int, bar&); void barNeeded(int); void callfoo() { foo(boost::bind(&barNeeded, _1, _2)); foo(boost::bind(&barNotNeeded, _1)); } void foo(tSlot& s) { bar b; expensive_calculation(b); s(1, b); } ---- How can I prevent expensive_calculation if the function barNotNeeded was bound to tSlot? Best regards Olaf Krzikalla

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Help with deduced template parameters
by Chris Ross 02 Jun '08

02 Jun '08

Forgive me if the answer ends up being strictly C++, rather than Boost. But, I have a template class that I would rather be able to deduce it's single [current] template parameter rather than having to specify it. I'm wondering if boost::function or boost::functional might make this easier for me to accomplish. My functor class is passed to a method similar to std::for_each, and that template functor class is: /*! Detach all members of the EntityList via stop_messaging. * \todo I suspect there's a way to make this not require template * arguments at instantiation, but at the moment it's being used * as: * mutexed_for_each(detach_all<typeof(arg)>(arg)); */ template <typename List> class detach_all { public: detach_all(const List &e) : list(e) {} template <class T> void operator ()(T*ent) const { if (dynamic_cast<Messageable*>(ent)) { std::for_each(list.begin(), list.end(), stop_messaging(dynamic_cast<Messageable*>(ent))); } } private: const List &list; }; If I make the class not be a template, but instead make the constructor a template member, it would be able to determine the template parameter List from the argument to the constructor. However, I'm then unable to keep a reference to the List argument to the constructor, which I need during the operator() invocation. Am I missing something about templates that I don't know? Or, is this just not possible with C++ templates, and in which case, can I use one of the boost libraries to help? Thanks much. - Chris

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Re: [Boost-users] Problems using pre-compiled boost libraries with Visual Studio 2005
by Fanara, Mark A (GE Infra, Transportation) 02 Jun '08

02 Jun '08

Trigve - Installing SP1 corrected the problem. Thanks! Mark

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Re: [Boost-users] Boost interprocess map in shared memory
by Jan Suchý 02 Jun '08

02 Jun '08

Hallo Ion, it's perfect. It's working now very well. I have used the v 1.35 solution. I am planning to port the application to the HP-UX from Linux. Do you see any problems to use interprocess module 1.35 on that platform? Thank you, have a nice day, Jan Suchy Date: Fri, 30 May 2008 21:22:45 +0200 From: Ion Gazta?aga <igaztanaga(a)gmail.com> Subject: Re: [Boost-users] Boost interprocess map in shared memory To: Boost User List <boost-users(a)lists.boost.org> Message-ID: <48405405.7010801(a)gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Jan Such? wrote: > Now, I want to have library, where i want to find previously created shared segment and read it more-times. > But I do not want to open it on every runQ function call. > I need to open this segment only once and use it more-times when runQ in lib is called. > > I tried this: The problem is that managed_shared_memory is not copyable. With current trunk code you could move it from localsegment to segment: managed_shared_memory localsegment(open_only, "MySharedMemory"); segment = move(localsegment); //localsegment is now in default-constructed state For 1.35 code allocate it through new (not compiled, this might contain errors): std::auto_ptr<managed_shared_memory> segment_ptr; int init() { segment_ptr.reset (new managed_shared_memory (open_only, "MySharedMemory") ); } Regards, Ion

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[Test] Documentation confusion
by Maik Beckmann 02 Jun '08

02 Jun '08

Hello, I am confused about the boost.test documentation. There are docs in trunk and after some hours of digging via gmane if found this one http://www.patmedia.net/~rogeeff/html/index.html index.html in trunk : ... Revised: 28 February, 2006 index.html external link: Copyright © 2001-2007 Gennadiy Rozental ... My impression is that the 2007 version is much more comprehensive. Why isn't the most recent one in trunk? Do the trunk docs got a link the the external docs? -- Maik

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[test] Using the Unit Test Framework in Xcode 3 howto
by Richard Dingwall 02 Jun '08

02 Jun '08

Hi guys, I've written a short tutorial on getting up and running with the Boost Unit Test Framework in Xcode 3, including getting the IDE to parse test results. You can read it here: http://richarddingwall.name/2008/06/01/using-the-boost-unit-test-framework-… Richard

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