May 2014 - Boost-users - lists.preview.boost.org

Re: [Boost-users] [serialization] deserialized instance empty even though proper serialize methods called [Honeywell Internal]
by Hickman, Steve (AdvTech) 30 May '14

30 May '14

Classification: Honeywell Internal I should have been more explicit in my original post. All serialization/deserialization is being done with base class pointers. I have a set of tests where I discovered the problems of serializing/deserializing with different pointer types that you identify below - so I've avoided that. What you suggest for the test program is essentially what I've done in my tests. One thing I did find in review is that somehow the serialize methods were marked protected rather than private. Fixing that partially corrected the problem. Now the deserialization "sticks" for all of the base class objects deserialized through the base class pointer (the data is in the fields after exiting the serialize process). For derived class objects deserialized through a base class pointer, I'm using xml_archive and stepping through the code. Here's what I see: First, one thing I notice: It appears that the system thinks tracking is on (line 476 of basic_iarchive.cpp: tracking is true) even though I've consistently said BOOST_CLASS_TRACKING(fully_qualified_classname,boost::serialization::track_never); In the .cpp files of all serialized classes. This shouldn't matter because I never read references to prior instances, but it may indicate a problem. The correct constructors are called in load_construct_data and the correct serialize methods are called. Further, at the end of the derived class serializer, all the fields contain the correct data - so it is loading correctly from the archive. The deserialize works up through the return from line 516 of iserializer.hpp (call to ar.load_pointer()) (at the topmost level - I have no embedded pointers in the objects I'm using to test with). T continues to have the values loaded. The call on line 527 of iserializer.hpp to pointer_tweak() appears to be causing the problem. It returns a null pointer. This means that the second portion of the nvp at the top level is now a null pointer, and I've lost what was loaded. I should also note at this point that all of the relevant classes have virtual destructors. This is the only virtual method they have. Note that all of the methods on these classes are declared with the appropriate DLL import/export (since this is built as a DLL). I should also note that I was wrong from my final reply on my previous post that the warnings on locally defined symbol 'symbol' imported in function 'function' had disappeared. They only disappeared because I was inadvertently doing incremental links. My initial attempts to resolve this issue have not apparently been successful. While the Microsoft documentation indicates that the code will still work (but just run slower) in the presence of these warnings, is it possible that the downcast in pointer_tweak() is failing because of this? I am endeavoring to correct this, but I'm a bit surprised at how the Microsoft compiler appears to be unable to chain macro definitions. --- Steve H. From: Robert Ramey [mailto:robertmacleranramey@gmail.com] Sent: Thursday, May 29, 2014 2:03 PM To: boostusers(a)googlegroups.com Cc: robertmacleranramey(a)gmail.com; boost-users(a)lists.boost.org; boost-users(a)lists.boost.org; Hickman, Steve (AdvTech) Subject: Re: [Boost-users] [serialization] deserialized instance empty even though proper serialize methods called [Honeywell Internal] OK - this should work. But in a few rare cases it won't. Usually this due to a very unusual corner case. That case is were something isn's de-serialized exactly as it was serialized. a) serializing through a derived pointer de-serialization through a base class pointer fix - even though one knows the derived class when serializing, serialize through a pointer to the base class - effectively using an implicit cast b) some other bizarre cases I don't remember. make a pair of test program which tests your serialization. a) use xml_archives b) program A should invoke both e main(){ ... X xp1 = new X; oar << xp1; ... X xp2; iar >> xp2; assert(*xp1 == *xp2); } c) split b above into two programs Robert Ramey ============================================================================================================================================================================================================ This message classified as Honeywell Internal by Hickman, Steve (AdvTech) on Friday, May 30, 2014 at 7:33:06 AM. The above classification labels are in accordance with the Honeywell Corporate Classification Policy. The information contained in this electronic message is confidential and intended only for the use of the individual/entity named above, and the information may be privileged. If you, the reader of this message, are not the intended recipient or an employee or agent responsible to deliver this message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender and delete the original message. ============================================================================================================================================================================================================

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Fix for annoying bug / library maintenance
by Filip Konvička 30 May '14

30 May '14

Hi, https://svn.boost.org/trac/boost/ticket/4964 This is out there for years. To me this seems to be clearly explained and a fix is provided, but apparently all bugs assigned to 'bgubenko' aren't monitored (for years there has been no reaction). So is there a way of getting the fix ever applied? Or are such unmaintained libraries just doomed to eventually die, despite the efforts of the people reporting bugs and posting patches? Thanks, Filip

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[unordered] Merging unordered maps
by Pete bartlett 29 May '14

29 May '14

I have a performance hotspot when merging a few unordered_maps of the same type into a master unordered_map (also of the same type) Currently I am doing Foreach( auto const& submap ,submaps ) Master.insert( submap.begin() , submap.end() ); This seems to be somewhat wasteful because the insert is (I think) computing hashes that the submaps already "know". Can I improve on this - without changing Boost? - without changing the boost interface, but changing the implementation (eg specialising the insert for certain iterator types)? - some more intrusive change? If the second or third option, would the maintainer be willing to consider merging the change into Boost proper? Thanks, Pete

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[boost][metaprogramming] Looking for a good reference
by Kyle Ketterer 29 May '14

29 May '14

Hey all, I want to learn more about template (meta) programming. Including, type generators, adapters, etc. Looking for a good C++11 style reference. Any recommendations on books/material? Thanks

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naming a test
by Eric Prud'hommeaux 29 May '14

29 May '14

boost/libs/test/example/external_main_example_1.cpp provides an example of a dynamical test suite tree. The invocation of add( BOOST_TEST_CASE(boost::bind(&free_test_function, 1, 1))); results in unpleasant names like "boost::bind( &free_test_function, 1, 2 )" . I used the preprocessor output to override the 2nd arg to make_test_case with a name of my choosing: ts->add(boost::unit_test::make_test_case (boost::unit_test::callback0<> (boost::bind( &free_test_function, 1, 2)), boost::unit_test::const_string( minor, 1))); This works (pretty names and invocable with the logical run_test) but I have no particular confidence that this will survive version changes as well as would BOOST_TEST_CASE. Is there a better way to do this? (stand-alone example attached) -- -ericP office: +1.617.599.3509 mobile: +33.6.80.80.35.59 (eric(a)w3.org) Feel free to forward this message to any list for any purpose other than email address distribution. There are subtle nuances encoded in font variation and clever layout which can only be seen by printing this message on high-clay paper.

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[Graph] Newbie on A*
by Ken Kazinski 29 May '14

29 May '14

Sensei, I think a simple solution is to use a counter. int Count = 0; for(std::size_t v = source_node; ; v = p[v]) { Count++; if (Count > Distance) { break; } }

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Re: [Boost-users] [serialization] deserialized instance empty even though proper serialize methods called [Honeywell Internal]
by Hickman, Steve (AdvTech) 29 May '14

29 May '14

Classification: Honeywell Internal All serialized classes have BOOST_CLASS_EXPORT_IMPLEMENT(fully_qualified_class_name) in the .cpp file (at the end of file) BOOST_CLASS_EXPORT_KEY(fully_qualified_class_name) in the .hpp file outside of all namespaces (at the end of file) In addition, I have a static template (templated on Archive type) method that calls ar.register_type for all serialized library classes. This method is called for both the output and the input archive before any serialization is done. This insures that all the library classes are registered with the archive in the same order. I do not attempt to register classes that I have not defined (e.g. std::string, ...). I do include the serialization headers for these types. (e.g. <boost/serialization/string.hpp>,...) I found that just using the macros was insufficient. In that case, the proper serialize methods were not called by the deserializing application (serialization worked fine). Adding the call that registers the library classes on both the input and output archives results in the proper serialize methods being called on both serialization and deserialization. However, even with this, the fields in the instance after deserialization have only default values. I did not detect any serialization exceptions during either serialization or deserialization. Note that I get the same behavior if I use manually created default constructors (AFAICT all my default constructors initialize all members to something). I do not get any uninitialized data exceptions. --- Steve H. From: Robert Ramey [mailto:robertmacleranramey@gmail.com] Sent: Thursday, May 29, 2014 9:28 AM To: boostusers(a)googlegroups.com Cc: boost-users(a)lists.boost.org; boost-users(a)lists.boost.org; Hickman, Steve (AdvTech) Subject: Re: [Boost-users] [serialization] deserialized instance empty even though proper serialize methods called When running tests where the same EXE serializes then deserializes everything works (I'm serializing to/from XML, text and binary). When running tests where I serialize in one EXE then deserialize in another EXE, (using text archives on both sides) the serialization works fine and the deserialization appears to work fine (all the appropriate deserialize methods are called), but the resulting object contains none of the data. The data is arriving at the receiving/deserializing application as a string which is then placed in a stringstream and that is used to initialize a text_iarchive. The serialize methods use BOOST_SERIALIZATION_NVP since this is set up to handle XML as well. After each line such as this: ar & BOOST_SERIALIZATION_NVP(valid); I would expect the referent member variable to be set, but it does not change. Nor has anything changed when examining the created instance after deserialization has completed. Look into the documentation for the topic - "registration". When serializing only through pointers, one needs to give the compiler some more info on what the base types are. Look for topics "register" and EXPORT Robert Ramey ============================================================================================================================================================================================================ This message classified as Honeywell Internal by Hickman, Steve (AdvTech) on Thursday, May 29, 2014 at 11:28:00 AM. The above classification labels are in accordance with the Honeywell Corporate Classification Policy. The information contained in this electronic message is confidential and intended only for the use of the individual/entity named above, and the information may be privileged. If you, the reader of this message, are not the intended recipient or an employee or agent responsible to deliver this message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender and delete the original message. ============================================================================================================================================================================================================

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[serialization] deserialized instance empty even though proper serialize methods called
by Hickman, Steve (AdvTech) 29 May '14

29 May '14

I'm using Boost.Serialization (v 1.55) on a 64 bit Win7 machine using VS 2012. I'm building the library containing all the classes to be serialized as a DLL. None of the classes have manually defined constructors (so I'm getting the compiler created constructors). All serialization is done through pointers. Most of the classes for a single class hierarchy of up to 5 inheritance levels, although there is a second class hierarchy with only 2 levels and a number of classes that do not use inheritance. When running tests where the same EXE serializes then deserializes everything works (I'm serializing to/from XML, text and binary). When running tests where I serialize in one EXE then deserialize in another EXE, (using text archives on both sides) the serialization works fine and the deserialization appears to work fine (all the appropriate deserialize methods are called), but the resulting object contains none of the data. The data is arriving at the receiving/deserializing application as a string which is then placed in a stringstream and that is used to initialize a text_iarchive. The serialize methods use BOOST_SERIALIZATION_NVP since this is set up to handle XML as well. After each line such as this: ar & BOOST_SERIALIZATION_NVP(valid); I would expect the referent member variable to be set, but it does not change. Nor has anything changed when examining the created instance after deserialization has completed. What is could be causing this/ how do I fix it? Steve Hickman System Architect, Flight Deck of the Future 480-236-8367

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[test]Legacy support - Boost 1.34.1 with MSVC 6
by Kerry, Richard 29 May '14

29 May '14

I've just started trying to use Boost's Test module. Trouble is I'm still stuck with Visual Studio 6(SP6), so I believe I need to stick with Boost 1.34.1 as the last properly supported for VC6. I'm having trouble getting the examples even to compile (ie exec_mon_example.cpp). Does anyone have any pointers to known incompatibilities between Boost 1.34.1 and VC6SP6 ? Or whether there is a more recent version where the Test module will work with VC6 ? I am well aware of how old VC6 is and would like to move forward. The major aim of getting Boost.Test working with VC6 is to give some confidence that any port to VC12 is working satisfactorily. Regards, Richard. Richard Kerry BNCS Engineer, SI SOL Telco & Media Vertical Practice T: +44 (0)20 3618 2669 M: +44 (0)7812 325518 Lync: +44 (0) 20 3618 0778 Room G300, Stadium House, Wood Lane, London, W12 7TA richard.kerry(a)atos.net<mailto:richard.kerry@atos.net>

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[preprocessor] BOOST_PP_REPEAT with multiple "data"
by Igor R 29 May '14

29 May '14

Hello, I'm trying to make a macro for the following case (essentially, I have to translate a run-time decision to a compile-time one): switch(i) { case 1: my_func(arg, offsetof(my_struct, arr[1].my_field))); break; case 2: my_func(arg, offsetof(my_struct, arr[2].my_field))); break; // etc. up to 10 } If I could hard-code the whole function call into the macro, I could do something like this: #define EXPR(unused, x, text) my_func(arg, offsetof(my_struct, arr[x].my_field))); break; #define MY_MACRO(x) \ switch(x)\ {\ BOOST_PP_REPEAT(x, EXPR, _)\ } However, I'd like to pass "arg" and "my_field" as parameters to this macro. What would be the right way to do this? Thanks.

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