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boost::serialization, binary archive contents
by Dan 29 Dec '09

29 Dec '09

Hi All, Im not sure if this the correct mailing list or not.. in fact im not sure if i'm even going about this the right way.. forums are so much easier.. Im using the boost::serialization library, im attempting to serialize an image file from the freeimage library. It is working beautifully if i serialize to a text archive however, binary archives fail to load with a "stream error" exception. With the freeimage library i can save the image to memory and then retrieve the pointer to the start memory address and also retrieve the size. With this information I attempt the following (NOTE, "io" is the freeimage memory stream (fipMemoryIO) which is returning the memory pointer and the size): void save(Archive & ar, const unsigned int version) const { BYTE * pData; DWORD dwSize; io.acquire(&pData1, &dwSize); ar & dwSize; boost::serialization::array<BYTE> ao = boost::serialization::make_array<BYTE>(pData, dwSize); ar & ao; } void load(Archive & ar, const unsigned int version) { BYTE * pData; DWORD dwSize; ar & dwSize; pData = new BYTE[dwSize]; boost::serialization::array<BYTE> ao = boost::serialization::make_array<BYTE>(pData, dwSize); ar & ao; // <----------- This throws an exception } The above throws the exception.. even though it succeeds with a text archive. What is even more frustrating is that if (when saving) the contents pData1 points to are changed, when loading there is no exception. (Obviously the bitmap would be corrupt but thats beside the point). void save(Archive & ar, const unsigned int version) const { BYTE * pData; DWORD dwSize; io.acquire(&pData1, &dwSize); ar & dwSize; memset(pData1, 0xAB, dwSize); // <--- Add this line an no exception is thrown. boost::serialization::array<BYTE> ao = boost::serialization::make_array<BYTE>(pData, dwSize); ar & ao; } I am at a loss. If i want to write x number of bytes it should write x number of bytes no matter what those bytes are.. I must be doing something wrong because this just doesnt make sense. The exception is always thrown in basic_binary_iprimitve.hpp if(scount != s) boost::serialization::throw_exception( archive_exception(archive_exception::stream_error) ); Regards, Dan

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[typeof] Determining if a type has been registered or not at compile time
by Edward Diener 27 Dec '09

27 Dec '09

Is there any way one can determine whether a type has been registered or not with Boost.Typeof at compile time so that the information can be used in TMP ? I am thinking, of course, of the use of typeof in a template, where a template parameter may or may not be aregistered type when the template has been instantiated. I would like to provide my own TMP fallback code if the type has not been registered rather than see an immediate compiler error generated. Something like: boost::mpl::eval_if < boost::typeof::registered<T>, // this would be nice to have boost::mpl::identity<BOOST_TYPEOF_TPL(some_expression)>, boost::mpl::identity</* use another facility to get the type I want into a metafunction*/> >

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Interest check: Boost.Mock
by Peter Bindels 26 Dec '09

26 Dec '09

Hi all, Over the past three-quarters of a year I've been working (with three friends) on a mocking framework for C++. In our vision, it would be a good complement to Boost.Test for testing classes separate from interfaces required - it would improve the ability to unit-test the classes that tie others together and that implement higher-level algorithms. It does this by creating an object that is "derived" from a given class at runtime, and replacing the functions with functions that redirect to verifying logic. The verifying logic uses basic structures to record expectations and to verify they happened. These ways of creating an object at runtime and modifying it are highly compiler dependant but remarkably portable - as it runs on at least 3 different compiler series (GCC, MSVC, EDG-based) and 5 platforms (Windows XP, Windows CE, Linux, QNX, bare platform), with few modifications. The library has been released under the name "Hippo Mocks" already. I'm interested in submitting it to Boost for three reasons. First of all, I believe that there may be obvious or very interesting optimizations or expansions I do not notice. Second, as Christian has elaborated on already, having the Boost tag on the project makes it more noticed and more used. As it has taken quite a bit of time from me already I would like people to use it. Third, Boost.Test allows testing code but does not support mocking. In the environment of unit testing, anything that is not a base library benefits from mocking by abstracting away details that are irrelevant and that will break your test unnecessarily. For Boost the main changes would be superficial in the naming and in using more default libraries instead of a new implementation. For Hippo Mocks I've decided to make no assumptions in anything over C++98 so there's a full Tuple implementation and so on. If there's an interest I'll spend the evening porting the code to qualify for the Boost coding norms and upload it to the vault (if I can - but that should be OK). I would like you to take a look at the code and tell me what you think of it. Thanks for your time. Kind regards, Peter Bindels

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Information about BMock
by Sterkin, Asher 24 Dec '09

24 Dec '09

Gennady, Recently I've came across discussion about extending the Boost.Test framework with a mocking capabilities: http://old.nabble.com/Interest-check:-Boost.Mock-td23958875.html I've even found a new header file mock_object.hpp within the 1_41 distribution, but not any documentation yet. There was a question about BMock library I developed and presented about at BoostCon09. The main differentiator of BMock from the rest of C++ frameworks I'm familiar with (except maybe MockItNow) is that it does not require neither classes, nor virtual methods. It does use heavily BOOST.Preprocessor and, at certain degree, boost meta-programming capabilities. Even though it has some historical quirks BMock has two major advantages, in my view, unsurpassable yet: a) Ability to dynamically mock ANY function or method. The function definition header needs to be wrapped with a special BMOCK_FUNCTION macro. Opposite to MockItNow this proves a fully portable solution, which does not depend on profiler API or any other low-level compiler capabilities. a) Deep integration with Boost.Test library, most importantly with its diagnostics. So far it proved itself as an extremely useful tool for embedded software development in C/C++. Attached you will find BMock documentation (sorry, not Boost standard :(). Not everything is relevant and not everything should remain, but hopefully you will get an adequate impression about how does it work from the user perspective. As I explained it to Dave during the BoostCon 09 I do not think that BMock in its current state is suitable to be a separate contribution to the Boost library, nor do I think it should be. From the beginning the BMock was conceived as a lightweight (well, as much as possible) extension to Boost.Test. If you find it interesting I will be happy to send you all sources (not too much) and to discuss how to proceed further. Regards, Asher Sterkin Asher [cid:image001.png@01CA84E9.267C30C0] <http://twitter.com/asterkin> [cid:image002.png@01CA84E9.267C30C0] <http://www.twitpic.com/photos/asterkin> [cid:image003.png@01CA84E9.267C30C0] <http://disturbingthoughts-asher.blogspot.com/> [cid:image004.gif@01CA84E9.267C30C0] <http://www.linkedin.com/pub/asher-sterkin/3/106/10a> ________________________________ This message is confidential and intended only for the addressee. If you have received this message in error, please immediately notify the postmaster(a)nds.com and delete it from your system as well as any copies. The content of e-mails as well as traffic data may be monitored by NDS for employment and security purposes. To protect the environment please do not print this e-mail unless necessary. An NDS Group Limited company. www.nds.com Gennady, Recently I’ve came across discussion about extending the Boost.Test framework with a mocking capabilities: [1]http://old.nabble.com/Interest-check:-Boost.Mock-td23958875.html I’ve even found a new header file mock_object.hpp within the 1_41 distribution, but not any documentation yet. There was a question about BMock library I developed and presented about at BoostCon09. The main differentiator of BMock from the rest of C++ frameworks I’m familiar with (except maybe MockItNow) is that it does not require neither classes, nor virtual methods. It does use heavily BOOST.Preprocessor and, at certain degree, boost meta-programming capabilities. Even though it has some historical quirks BMock has two major advantages, in my view, unsurpassable yet: a) Ability to dynamically mock ANY function or method. The function definition header needs to be wrapped with a special BMOCK_FUNCTION macro. Opposite to MockItNow this proves a fully portable solution, which does not depend on profiler API or any other low-level compiler capabilities. a) Deep integration with Boost.Test library, most importantly with its diagnostics. So far it proved itself as an extremely useful tool for embedded software development in C/C++. Attached you will find BMock documentation (sorry, not Boost standard L). Not everything is relevant and not everything should remain, but hopefully you will get an adequate impression about how does it work from the user perspective. As I explained it to Dave during the BoostCon 09 I do not think that BMock in its current state is suitable to be a separate contribution to the Boost library, nor do I think it should be. From the beginning the BMock was conceived as a lightweight (well, as much as possible) extension to Boost.Test. If you find it interesting I will be happy to send you all sources (not too much) and to discuss how to proceed further. Regards, Asher Sterkin Asher [2]twitter [3]twitpic [4]favicon [5]Linkedin _________________________________________________________________ This message is confidential and intended only for the addressee. If you have received this message in error, please immediately notify the postmaster(a)nds.com and delete it from your system as well as any copies. The content of e-mails as well as traffic data may be monitored by NDS for employment and security purposes. To protect the environment please do not print this e-mail unless necessary. An NDS Group Limited company. www.nds.com References 1. http://old.nabble.com/Interest-check:-Boost.Mock-td23958875.html 2. http://twitter.com/asterkin 3. http://www.twitpic.com/photos/asterkin 4. http://disturbingthoughts-asher.blogspot.com/ 5. http://www.linkedin.com/pub/asher-sterkin/3/106/10a

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[optional] Strict Aliasing Warnings on Trunk
by Dean Michael Berris 24 Dec '09

24 Dec '09

I've recently been seeing this error more and more especially on GCC with -Wall: /home/dean/boost/boost/optional/optional.hpp:407: warning: dereferencing pointer ‘<anonymous>’ does break strict-aliasing rules /home/dean/boost/boost/optional/optional.hpp:427: note: initialized from here and: /home/dean/boost/boost/function/function_base.hpp:321: warning: dereferencing type-punned pointer will break strict-aliasing rules /home/dean/boost/boost/function/function_base.hpp:325: warning: dereferencing type-punned pointer will break strict-aliasing rules This is on Linux and GCC 4.4.1. I'm not an expert in this regard but is there a way to either silence or avoid these warnings? Anything you want me to try from my end? Thanks in advance and I hope this helps. -- Dean Michael Berris blog.cplusplus-soup.com | twitter.com/mikhailberis linkedin.com/in/mikhailberis | facebook.com/dean.berris | deanberris.com

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Using Boost.Atomic for shared_ptr
by Phil Endecott 24 Dec '09

24 Dec '09

Dear All, I have just had a quick look at how easily shared_ptr could be adapted to use Helge's proposed Boost.Atomic. To me it looks very simple, but maybe someone who knows more about all this could have a look? I took the non-threaded implementation in sp_counted_base_nt.hpp as a starting point, and simply changed the two counts from long to boost::atomic<long> : boost::atomic<long> use_count_; // #shared boost::atomic<long> weak_count_; // #weak + (#shared != 0) Then, the majority of the methods don't need to change since the atomic template provides atomic versions of e.g. operator++. The one that does need more work is add_ref_lock, which I've implemented as follows: bool add_ref_lock() // true on success { while (1) { long c = use_count_; if (c == 0) return false; if (use_count_.compare_exchange_weak(c,c+1)) return true; } } There is also the question of memory barriers. I understand that things like operator++ provide the most pessimistic memory barriers, so ideally these should be replaced with calls that use the right barriers. Does anyone have any thoughts about how this would compare with the current custom assembler implementations? Cheers, Phil.

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[fusion] change on trunk breaking proto
by Eric Niebler 23 Dec '09

23 Dec '09

Hi Fusion gurus. I'm chasing an elusive bug that the following Proto test has exposed: http://beta.boost.org/development/tests/trunk/developer/output/RW_WinXP_VC-… All is well on the release branch, but on trunk, Proto's examples.cpp test is failing -- but only on MSVC! I suspect Fusion because if I replace the version of Fusion on trunk with the one on release all is well. (Caveat: when I do this, I also need to make a corresponding change to the as_callable function object in proto/transform/fold.hpp to accommodate the changed argument order of fusion::fold's functor.) It seems something is causing MSVC to prematurely instantiate a template used in a Proto transform, but I can't see what. I first suspected the recent changes to fusion::fold, but that seems not to be the case. If I just take the release version of fusion::fold, the problem still manifests. The problem must be elsewhere. Does anyone from Fusion team want to give this a crack? I'll be happy to help. -- Eric Niebler BoostPro Computing http://www.boostpro.com

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Interprocess message queue implementation
by Alex Miller 22 Dec '09

22 Dec '09

Hello, I have been looking over the implementation of Boost.Interprocess's message queues, and have become slightly confused as to the reasoning for how it was designed. Assuming my understanding is correct, it allocates a piece of shared memory, and then constructs a message queue within that piece of memory. Is there a reason that this was done in favor over implementing it by using SystemV's message queues ( the one located in <sys/msg.h> )? Thanks, Alex Miller

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Re: [boost] [date_time] quarters as new durations?
by pete＠pcbartlett.com 22 Dec '09

22 Dec '09

On Tue 22/12/09 13:27 , "Stewart, Robert" <Robert.Stewart(a)sig.com> wrote: > Jeff Garland wrote: > > Stewart, Robert wrote: > > > Thomas Lemm wrote: > > >> I am happily using the boost date_time library and I plan to > > >> extend it towards including quarters as new (gregorian) date > > >> durations, just the way months are included already > > >> (excluding parsing of quarters) > > > > > > Why excluding parsing? That would imply only partial > > > support relative to other durations, right? > > > > > Well, so quarters turns out to be like months as far as > > durations go -- that is, it's mathematical like days and > > weeks. So the big drawback you face is dealing with the > > associated "fuzzy math". For example, what's the result > > of > > > > date("2008-Feb-28") + quarters(1) = ? > > date("2008-Feb-27") + quarters(1) = ? > > > > Month durations play some games to handle this problem (see > > docs for details) which quarters could adopt. But if you > > adopt the month rules then I don't thing you buy much more > > than simply writing > > > > const months quarters = months(3); > That's an excellent point. I don't think the fuzzy math approach is > appropriate for quarters because they have a precise definition: 1/4 > of a year. Months are less precise, though 365 / 4 is not a whole > number, of course. Possibly opening a can of worms here, but a quarter in my line of work is invariably three months. If your mileage varies, then there could be a problem in providing a fully meaningful quarter duration type if people think it means different things. > There is probably still a need to use some fuzzy math in order to > determine the calendar date for quarter boundaries. Quarters are > usually associated with a fiscal year and there are different > definitions of those, so you probably need to add fiscal year support > and make quarters a derived concept. > > There's also an argument against adding quarters as a > > duration. I have an app somewhere in which I have quarter > > defined as a date_period so I could write: > > > > date_period q = quarter(2009, 1); > > > > To me at least this seems like the more likely application. > I agree. I didn't consider the ramifications of duration versus > period. The issue routinely occurs with months already though. Month durations and date_periods spanning a specific month already have to work closely with each other: date_period month_containing(date d) { return date_period(date(d.year(),d.month(),1) , months(1) ); } so it may not be a big issue.

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[date_time] quarters as new durations?
by Thomas Lemm 22 Dec '09

22 Dec '09

Hi, I am happily using the boost date_time library and I plan to extend it towards including quarters as new (gregorian) date durations, just the way months are included already (excluding parsing of quarters) Now my question: What are the chances that his change might make it into the boost date_time library? Is there some interest in this feature, if so I would provide a patch to update source and documentation to include the quarters as a new duration. Please let me know, Kind regards Thomas Lemm

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