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[serialization] Notes from a new boost user
by Michael Behrns-Miller 01 Jul '05

01 Jul '05

> I've become very skeptical of my ability to predict how other programmers > are going to address things. I'm willing to wait and see. > > So I'm anxious to see where this goes. If in fact we do get a wave of > users with problems, I'll be forced to modify my point of view in the > face of the facts. If (almost) no one complains (perhaps unlikely) then > there will be no issue. If there are a fair number of complaints - but > it turns out that a significant portion are due to real mistakes - we > might be in for another debate. But given more data, I would expect it > to be of a different character. If it turns out (almost) none of the > cases are real problems, then I'll have to accept as a fact that its a > bad idea. As a new boost user I thought I would humbly submit some feedback. Forgive me if I missed nuances of the existing debates. 1) I love the serialization library, I'm sure many of us have done similar code before, and it's great to see work towards a standardized solution. Really useful, thanks Robert! 2) The new "const required to save" restriction bit me, took a day or two to work through the mailing list and #boost to figure out the problem. Is there a way to make the end-of-the-chain error message (`boost::STATIC_ASSERTION_FAILURE<false>' does not have member `value') more clear? I would rate the severity of the difficulty a 2 or 3 out of 10, from a new user's perspective. It seemed intuitive enough once I understood the requirement. Putting the serialization save calls within a const save(archive) function of the object being serialized made it a non-issue for me. I haven't used it enough to say I won't run into the const issue again, but at least I know about it now. 3) I realize I can split serialize() into separate load/save functions. However, I appreciate the recommendation to use one serialize() function, where the load/save order is easier to maintain. However again, I absolutely need (I think :>) to know, within that function, if I am loading or saving. It's the only way I can efficiently handle versioning or handle dynamic allocations, and still use one serialize() function, as far as I can tell. Bottom line: I now have isSaving(archive)/isLoading(archive) functions, can these be added to the library? Or am I approaching this wrong? As I've said, I'm brand new at this. I'm providing this feedback for two reasons: to give you an idea of what I ran into as a new user, and to get suggestions on anything I'm approaching in the wrong way. Thanks again boost.

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[serialization] Notes from a new boost user
by Michael Behrns-Miller 01 Jul '05

01 Jul '05

> I've become very skeptical of my ability to predict how other programmers > are going to address things. I'm willing to wait and see. > > So I'm anxious to see where this goes. If in fact we do get a wave of > users with problems, I'll be forced to modify my point of view in the > face of the facts. If (almost) no one complains (perhaps unlikely) then > there will be no issue. If there are a fair number of complaints - but > it turns out that a significant portion are due to real mistakes - we > might be in for another debate. But given more data, I would expect it > to be of a different character. If it turns out (almost) none of the > cases are real problems, then I'll have to accept as a fact that its a > bad idea. As a new boost user I thought I would humbly submit some feedback. Forgive me if I missed nuances of the existing debates. 1) I love the serialization library, I'm sure many of us have done similar code before, and it's great to see work towards a standardized solution. Really useful, thanks Robert! 2) The new "const required to save" restriction bit me, took a day or two to work through the mailing list and #boost to figure out the problem. Is there a way to make the end-of-the-chain error message (`boost::STATIC_ASSERTION_FAILURE<false>' does not have member `value') more clear? I would rate the severity of the difficulty a 2 or 3 out of 10, from a new user's perspective. It seemed intuitive enough once I understood the requirement. Putting the serialization save calls within a const save(archive) function of the object being serialized made it a non-issue for me. I haven't used it enough to say I won't run into the const issue again, but at least I know about it now. 3) I realize I can split serialize() into separate load/save functions. However, I appreciate the recommendation to use one serialize() function, where the load/save order is easier to maintain. However again, I absolutely need (I think :>) to know, within that function, if I am loading or saving. It's the only way I can efficiently handle versioning or handle dynamic allocations, and still use one serialize() function, as far as I can tell. Bottom line: I now have isSaving(archive)/isLoading(archive) functions, can these be added to the library? Or am I approaching this wrong? As I've said, I'm brand new at this. I'm providing this feedback for two reasons: to give you an idea of what I ran into as a new user, and to get suggestions on anything I'm approaching in the wrong way. Thanks again boost.

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Boost.Build v2 with VC8
by Johan Johansson 01 Jul '05

01 Jul '05

How do you do it? I've tried adding using msvc : 8.0 to user.config and I've tried using msvc : vc-8_0 since that didn't appear to work. At that point I got the message that the python lib wouldn't be build - but I've set both PYTHON_ROOT and PYTHON_VERSION to the satisfaction of Boost.Build v1. Can someone please tell me what to configure and the exact command line I should use to build it? I've already spent 2 hours running in circles in the docs and that doesn't seem to get me anywhere. Thanks, Johan

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[serialization] Regressions?
by Vladimir Prus 01 Jul '05

01 Jul '05

Hi Robert, I've just updated by Boost tree and run in a number of compile errors. One is pretty easy -- I've committed the attached trivial patch to split_member.hpp. Another is this: ....boost/boost/archive/detail/oserializer.hpp:551: error: incomplete type `boost::STATIC_ASSERTION_FAILURE<false>' does not have member `value' instantiated from this code of mine: ofstream ofs(av[2]); boost::archive::binary_oarchive oa(ofs); oa << *data_builder.finish(); Where 'finish' returns auto_ptr<Data>. It's looks like serialization checks if the serialized type is 'const' and if not, complains. Basically, it's some heuritic to prevent saving on-stack object (though I don't understand why it would work at al). I find this a bit too much . I have no reason whatsoever to make 'finish' return auto_ptr<const Data>. And writing oa << const_cast<const Data&>(*data_builder.finish()); looks very strange. And modifying all places where I get this error is not nice too. So, can this static assert be removed? Then, I get ambiguity in iserializer.hpp, in this code: #ifndef BOOST_NO_FUNCTION_TEMPLATE_ORDERING template<class Archive, class T> inline void load(Archive &ar, const serialization::nvp<T> &t){ load(ar, const_cast<serialization::nvp<T> &>(t)); } For some reason, both boost::archive::load and some other 'load' in 'boost' namespace (part of earlier serialization lib) that I still use are considered overload candidates. Adding explicit boost::archive:: fixes this. See attached patch. Then I get error at this code: ar << boost::lexical_cast<std::string>(*this); The error message is: error: no match for 'operator<<' in 'ar << boost::lexical_cast(Source) [with Target = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, Source = lvk::nm_model::BlockFormula]()' /space/NM/boost/boost/archive/detail/interface_oarchive.hpp:75: error: candidates are: Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, Archive = boost::archive::binary_oarchive] ...unrelated operator<< definitions snipped... Apparently, passing rvalue to "T&" does not work. Yes another attached patch fixes this issue. - Volodya

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Boost regression notification (2005-07-01)
by Douglas Gregor 01 Jul '05

01 Jul '05

Boost regression test failures ------------------------------ Report time: 2005-07-01T15:12:34Z This report lists all regression test failures on release platforms. WARNING: The following libraries have failing regression tests but do not have a maintainer on file. Once a maintainer is found, add an entry to libs/maintainers.txt to eliminate this message. random preprocessor io Detailed report: http://engineering.meta-comm.com/boost-regression/CVS-HEAD/developer/issues… 337 failures in 14 libraries: bind (1) io (2) iostreams (1) iterator (2) preprocessor (1) program_options (13) python (56) random (3) regex (2) serialization (239) spirit (5) test (6) thread (2) wave (4) |bind| mem_fn_eq_test: intel-win32-8_1 |io| ios_state_unit_test: intel-win32-8_1 intel-win32-8_1 |iostreams| counter_test: vc-8_0 |iterator| filter_iterator_test: intel-win32-8_1 lvalue_concept_fail: intel-win32-8_1 |preprocessor| seq: cw-8_3 |program_options| cmdline_test: vc-7_0 cmdline_test_dll: mingw-3_4_2 vc-7_0 parsers_test: vc-7_0 parsers_test_dll: vc-7_0 positional_options_test_dll: mingw-3_4_2 unicode_test: vc-7_0 unicode_test_dll: cw-9_5-darwin gcc-3_3-darwin vc-7_0 variable_map_test: vc-7_0 variable_map_test_dll: vc-7_0 vc-8_0 |python| andreas_beyer: intel-win32-8_1 args: intel-win32-8_1 auto_ptr: intel-win32-8_1 back_reference: intel-win32-8_1 ben_scott1: intel-win32-8_1 bienstman1: intel-win32-8_1 bienstman2: intel-win32-8_1 bienstman3: intel-win32-8_1 builtin_converters: intel-win32-8_1 callbacks: intel-win32-8_1 const_argument: intel-win32-8_1 crossmod_exception: intel-win32-8_1 data_members: intel-win32-8_1 defaults: intel-win32-8_1 dict: intel-win32-8_1 docstring: intel-win32-8_1 embedding: intel-win32-8_1 enum: intel-win32-8_1 exception_translator: intel-win32-8_1 extract: gcc-3.3.6-linux intel-win32-8_1 implicit: intel-win32-8_1 injected: intel-win32-8_1 iterator: intel-win32-8_1 keywords: intel-win32-8_1 list: gcc-3.3.6-linux intel-win32-8_1 long: intel-win32-8_1 map_indexing_suite: intel-win32-8_1 minimal: intel-win32-8_1 multi_arg_constructor: intel-win32-8_1 nested: intel-win32-8_1 object: intel-win32-8_1 opaque: intel-win32-8_1 operators: gcc-3.3.6-linux intel-win32-8_1 pearu1: intel-win32-8_1 pickle1: intel-win32-8_1 pickle2: intel-win32-8_1 pickle3: intel-win32-8_1 pickle4: intel-win32-8_1 polymorphism: intel-win32-8_1 polymorphism2: intel-win32-8_1 properties: intel-win32-8_1 raw_ctor: intel-win32-8_1 return_arg: intel-win32-8_1 shared_ptr: intel-win32-8_1 slice: gcc-3.3.6-linux intel-win32-8_1 staticmethod: intel-win32-8_1 str: intel-win32-8_1 test_pointer_adoption: intel-win32-8_1 try: intel-win32-8_1 tuple: intel-win32-8_1 vector_indexing_suite: intel-win32-8_1 virtual_functions: intel-win32-8_1 |random| random_test: intel-win32-8_1 intel-win32-8_1 intel-win32-8_1 |regex| regex_regress: intel-win32-8_1 regex_regress_dll: intel-win32-8_1 |serialization| test_array_text_archive_dll: cw-9_5-darwin test_array_text_warchive_dll: cw-9_5-darwin test_array_xml_archive_dll: cw-9_5-darwin test_array_xml_warchive_dll: cw-9_5-darwin test_binary_text_archive_dll: cw-9_5-darwin test_binary_text_warchive_dll: cw-9_5-darwin test_binary_xml_archive_dll: cw-9_5-darwin test_binary_xml_warchive_dll: cw-9_5-darwin 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Going temporarily offline.
by Hubert Holin 01 Jul '05

01 Jul '05

Somewhere in the E.U., le 01/07/2005 Bonjour As of tonight and for about a month (Hurray!!!) I will be on vacation, and for the most part totally offline. So as not to possibly delay the 1.33 release, I state here clearly that anybody is welcome to check-in any (useful) change to the libraries I maintain (Quaternions, Octonions & Special Functions). As far as these libraries stand today, for the platforms that are taken into account for the release, no outstanding problem seem to remain (either the platform passes or is marked as an expected failure). There remains a vexing point with respect to some platforms (notably 64 bits platforms) where the libraries fail because of "long double" issues. I believe these are due to a bug (or severe QOI problem) in libstdc++, but unfortunately so far no progress seems to have been made to solve the problem if indeed libstdc++ is the culprit, and I am loath to mark these platforms as expected failures (heck, one of them I my development system!). I propose we leave these as they stand now, and re-investigate after the release. Merci et bonnes vacances! Hubert Holin

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Re: [boost] [serialization] Argument (was: Regressions?)
by Marcin Tustin 01 Jul '05

01 Jul '05

While the discussion continues regarding policy decisions in the serialization library, I think I might contribute the following observation, having only recently become a user of this library: The library has the feel of a library for building serialisation, and serialisation-based libraries, rather than a fully-featured library suitable for a programmer to pick up and start throwing objects at. In this regard, the documentation might make explicit the choices and policy decisions that users have to make, and the limitations that obtain (for example, you can't just pick up a text oarchive, and hook it to a text iarchive with connected streams have things Just Work(TM), which is quite reasonable, but not totally obvious) because of the way it has (largely necessarily) been implemented. Please understand that I am not saying that the library cannot simply be used for simple use-cases - quite the reverse, when you only want to do simple things, then the library does just work out of the box. However, things are rarely that simple for very long. It may help to think of the library this way.

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[regex] Boost.Regex and TR1 fundamentally broken?
by Eric Niebler 01 Jul '05

01 Jul '05

I've had a nagging feeling about character ranges and the TR1 regex proposal, so today I did some digging. I've found what I think is a showstopping issue for TR1 regex. I hope I'm wrong. The situation of interest is described in the ECMAScript specification (ECMA-262), section 15.10.2.15: "Even if the pattern ignores case, the case of the two ends of a range is significant in determining which characters belong to the range. Thus, for example, the pattern /[E-F]/i matches only the letters E, F, e, and f, while the pattern /[E-f]/i matches all upper and lower-case ASCII letters as well as the symbols [, \, ], ^, _, and `." A more interesting case is what should happen when doing a case-insentitive match on a range such as [Z-a]. It should match z, Z, a, A and the symbols [, \, ], ^, _, and `. This is not what happens with Boost.Regex (it throws an exception from the regex constructor). The tough pill to swallow is that, given the specification in TR1, I don't think there is any effective way to handle this situation. According to the spec, case-insensitivity is handled with regex_traits<>::translate_nocase(CharT) -- two characters are equivalent if they compare equal after both are sent through the translate_nocase function. But I don't see any way of using this translation function to make character ranges case-insensitive. Consider the difficulty of detecting whether "z" is in the range [Z-a]. Applying the transformation to "z" has no effect (it is essentially std::tolower). And we're not allowed to apply the transformation to the ends of the range, because as ECMA-262 says, "the case of the two ends of a range is significant." So AFAICT, TR1 regex is just broken, as is Boost.Regex. One possible fix is to redefine translate_nocase to return a string_type containing all the characters that should compare equal to the specified character. But this function is hard to implement for Unicode, and it doesn't play nice with the existing ctype facet. What a mess! -- Eric Niebler Boost Consulting www.boost-consulting.com

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Re: [boost] [home page] Marketing?
by Martin Bonner 01 Jul '05

01 Jul '05

----Original Message---- From: Beman Dawes [mailto:bdawes@acm.org] Sent: 01 July 2005 13:50 To: Boost mailing list Subject: [boost] [home page] Marketing? > If we go forward with this, I'll try to get quotes from one or two > other C++ luminaries to go in the "What do others say about Boost" > sub-section. >From http://www.research.att.com/~bs/abstraction.pdf: "The obvious solution for most programmers is to use a library that provides an elegant and efficient platform independent to needed services. Examples are BOOST ..." I'm sure the man would be prepared to give you a slightly punchier quote. On the other hand, quotes that people have made unprompted somehow feel more honest. The best I can find for Sutter is "Use the Boost, Luke", which is perhaps a bit nerdish for selling to managers. I can't find a thing for Andrew Koenig - google finds LOTS of things for "boost koenig", but they nearly all refer to Koenig lookup, and the rest seem to refer to "Accelerated C++". (I'm sure he /has/ said something complimentary, I just can't find it). -- Martin Bonner Martin.Bonner(a)Pitechnology.com Pi Technology, Milton Hall, Ely Road, Milton, Cambridge, CB4 6WZ, ENGLAND Tel: +44 (0)1223 441434

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Re: [boost] [function types] New tag type logic
by Greer, Joe 01 Jul '05

01 Jul '05

> From: David Abrahams <dave(a)boost-consulting.com> > > Rob Stewart <stewart(a)sig.com> writes: > > > > > > When classifying types, it is often necessary to test for any > > > one of several variations of an aspect. A common case is > > > ignoring an aspect which means to allow a match for any > > > variation of that aspect > > Please excuse me for jumping into the middle of this discussion. I am only a budding metaprogrammer, so that influences how I read things like this, so bear with me. With this phrasing, it is unclear to me whether the common case is "ignoring an aspect" or if it is really "allowing a match for any variation of an aspect" which I can do by "ignoring an aspect." > > Neither quoted sentence seems long or complex. Perhaps there > was something you snipped to which you were referring? > > Here's the full text of my suggestion: > > When classifying types, it is often necessary to test for any > one of several variations of an aspect. A common case is > ignoring an aspect which means to allow a match for any > variation of that aspect and is only useful when also testing > for other aspects. Ignoring an aspect means using an > "unspecified_*" tag. For example, allowing a match for any > decoration requires using the <tt>unspecified_decoration</tt> > tag. > In this paragraph, you are telling me that "ignoring an aspect" is "allow a match for any variation of that aspect" (sentence 2) and that "ignoring an aspect" is "using an "unspecified_*" tag" (sentence 3). The use of "means" in both sentences is awkward. It is also unclear that "allow a match for any variation of that aspect" is actually the same as "using an unspecified_* tag." I tend to be more conversational in my writing, but I would be tempted to write something like: When classifying types, it is often necessary to test for any one of several variations of an aspect. A common case is allowing a match for any variation of an aspect. This is done by ignoring that aspect and is implemented by using an "unspecified_*" tag. For example, to allow a match For any decoration would require using the <tt>unspecified_decoration</tt> tag. I just wanted to throw in my $.02. I'll go back into lurker mode now. :) Joe

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