September 2010 - Boost-users - lists.preview.boost.org

Boost.Math pow and __int64
by gast128 28 Sep '10

28 Sep '10

Hello all, Not sure if this zero warning policy is in effect, but if so maybe Boost can have a look at use of __int64 and pow (e.g. boost::math::pow<2, __int64> gives a warning)?

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[serialization] Deserialize by pointer without calling new/constructor
by Adam Verigin 28 Sep '10

28 Sep '10

I'm working on integrating Boost serialization into an OMNeT++ simulation as a means of saving a partial simulation state (to speed up statistical testing). The problem I am running into is related to the process of deserializing a derived-class object by a base-class pointer without tracking. As far as I can tell, in this case the serialization library normally: 1. Determines the most-derived type 2. Allocates memory for that type of object 3. Updates the pointer to point the the above allocated memory block 4. Invokes placement new and the default constructor (overloadable by load_construct_data) 5. Calls the class' serialize() or load() method on the newly-constructed object However, I have a case where I start out with an existing derived-class object that is partially initialized, and I just want to call the serialize() or load() method for it using a base-class pointer (i.e., no memory allocation since that's already done, and no constructor call since that's also already done.) Is this possible or am I trying to do something the serialization library is not meant for? Thanks, Adam Verigin

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Re : boost serialize - stack overflow for large problems
by "Jörg F. Unger" 28 Sep '10

28 Sep '10

The problem occurs at runtime. I 've figured out that the problem is due to the nested data structure. I have kind of a graph, where every node stores a pointer to the neighboring node. This means, once I start to serialize the first node, all the neighboring nodes have to be serialized as well, which finally ends up with at many recursive function calls as I have nodes. This is probably similar to a linked list, where once the first entry is serialized, a pointer to the next element is serialized and so on, which finally ends up with as many recursive function calls as there are element in the list. Is there a clever way to restructure the serialization (e.g. first serializing all the nodes, and in a second step, when the nodes have been created, serialize there connectivity without introducing two separate serialize routines?) JFU "Jörg F. Unger" wrote: > I have implemented the serialization routine for a rather complex > structure with many nested classes. The serialization seems to work > for small examples, however, for bigger data sets, I get a stack > overflow error. If I increase the stack size from 8MB to 20MB, the > examples seems to work. However, I'd like to optimize the code the > way that I do not need to increase the stack size (especially, since > not all users can do that themselves) Are you referring to compile time or runtime? > So here are my questions: > 1. Why is the required stack size different for different data sets > different. The structure of the datasets is identical, only the number > of data sets differs - so why is the recursive level different? The > only thing I can imagine is, that I have a class (container) with a > vector of objects. Each object stores a pointer to the container > class. Is it possible that once serialization in the container class > starts, that there is a recursive serialization pattern? This seems > to be support by the fact that the objects in the container class are > not serialized in the same way as they are stored in the container. The stack depth should be proportional to the depth of your class data. It should be easy to check this. Setup your debugger to trap on stack overflow. When it does, show a back trace. You should be able to easily determine the source of the stack usage. I could be some deeply recursive structure, a coding error or who knows. Do this analysis is much more time efficient than me trying to guess what the problem might be. > 2. How can I try to decrease the required stack size for the > serialization routines and is there a way to estimate the required > stack size for a specific problem a priori, so that I can throw an > exception with an error message manually instead of having a > segmentation fault. If the source is some sort of error - then there is not problem once the error is fixed. If the source is that there is VERY deep nesting of data structures, you'll just have to refactor the data. This isn't a hardship since you would likely have other issues generated by this besides serialization. Robert Ramey

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Boost Graphs - Betweenness Centrality
by Rupert Ogilvie 28 Sep '10

28 Sep '10

Hi all, I’m trying to implement the Betweenness Centrality Calculation in the Boost Graph Library. I’ve created a graph with the following attributes: typedef adjacency_list <vecS, vecS, undirectedS> Graph; Graph G1; But I’m struggling to get the Done object created right to pass into the calculation. If anyone has some example code or suggestions I’d be really grateful. Apologies if this is a really basic question but I’m very new to C++ and Boost! Many thanks in advance, Rupert

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Compiling / Linking Boost::RegEx for x64 targets fails
by Andi Clemens 28 Sep '10

28 Sep '10

Hi, I used the boost library installer from boostpro to install the 32 bit version on my system. All projects compile and link fine for the 32 bit target in Visual Studio 2005. But when I switch to the x64 platform target, I get linker errors. So I decided to compile boost myself, with the following command: bjam.exe --build-dir=e:\boost-build --build-type=complete --toolset=msvc --address-model=64 and installed the result in a separate lib_x64 folder in the boost installation from boostpro. All projects with the x64 target add this path to the linker settings. The libs are found, but when I compile the project, I get the following linker errors: http://pastebin.com/saQMtFwX All problems seem to be related to the regex library. I then created a complete new project with a simple source code, just for testing purposes: http://pastebin.com/QyQRiQ5p It compiles fine with the w32 target, but not with the x64 target (libary path has been changed accordingly). Is there any known issue when using regex with x64? Do I have to set some variables first to make this link correctly? Andi -- Neu: GMX De-Mail - Einfach wie E-Mail, sicher wie ein Brief! Jetzt De-Mail-Adresse reservieren: http://portal.gmx.net/de/go/demail

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[Fusion] Adapted struct with member optional<variant<A, B>> needs typedef
by PB 27 Sep '10

27 Sep '10

Hello, The following program (written in VS2008/VC9 with Boost 1.44) doesn't compile: #include <boost/fusion/include/adapt_struct.hpp> #include <boost/optional.hpp> #include <boost/variant/variant.hpp> #include <string> #include <vector> struct Word {std::string str;}; struct Text {std::string str;}; struct Transition { boost::optional<boost::variant<Word,Text>> token; }; BOOST_FUSION_ADAPT_STRUCT(Word,(std::string, str)) BOOST_FUSION_ADAPT_STRUCT(Text,(std::string, str)) BOOST_FUSION_ADAPT_STRUCT( Transition, (boost::optional<boost::variant<Word,Text>>, token) ) int main(int argc,char *argv[]) { return 0; } Compiler output: error warning C4002: too many actual parameters for macro 'BOOST_FUSION_ADAPT_STRUCT_FILLER_0'. <etc> If I introduce a typedef for the long type: typedef boost::optional<boost::variant<Word,Text>> TokenType; and change the adapt struct to use the shorter name, it works: BOOST_FUSION_ADAPT_STRUCT( Transition, (TokenType, token) ) Why is this, and what are the constraints on the types fed to BOOST_FUSION_ADAPT_STRUCT? Thanks, Pete

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[iostreams] Seeking with using stream<file_descriptor>::seekp() failes
by Timothy Madden 27 Sep '10

27 Sep '10

Hello Why do I get 'debug assertion failed: initialized_' when I try to seek on a boost::filesystem::stream<file_descriptor> ? I also tried with my own class seekable_fd: public device<seekable> { protected file_descriptor file_d; //.... }; to be use the device is seekable, and I get the same assert. I have boost 1.44.0, VS 2008, Win7 Thank you, Timothy Madden

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Could searching and indexing Boost docs might work better?
by Paul A. Bristow 27 Sep '10

27 Sep '10

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org [mailto:boost-users- > bounces(a)lists.boost.org] On Behalf Of Steven Watanabe > Sent: Thursday, September 16, 2010 3:47 AM > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] selective enabling/disabling of > BOOST_AUTO_TEST_CASE > > AMDG > > Suresh Kumar wrote: > > I have several tests in my unit test file each of them uniquely named > > using the function BOOST_AUTO_TEST_CASE. I may not need to run all of > > them always and as of now what I do is to comment out the tests which > > I dont want to run. > > > > Instead of commenting out code, is there any other way I can > > selectively enable or disable tests if i have created tests with > > BOOST_AUTO_TEST_CASE. > > > > You can control which tests are run on the command line See > http://www.boost.org/libs/test/doc/html/utf/user-guide/runtime-config/run- > by-name.html Well thanks Steven - Now that's something I have wanted to know but didn't dare ask ;-) But I have now squandered a few minutes trying again to find this information using Google (putting myself in the shoes of the OP). A search for "Running specific test units selected by their name" didn't get me to this page (on the first page at least). Adding site::boost.org helped reduce clutter from other unit test systems. Even "Running specific test units selected by their name" site:boost.org (note quotes mean search for exact text) didn't get to the current (or nearly) releases by name, and I didn't spot this page quickly. Using boost.org and entering "Running specific test units selected by their name" into the search box also didn't produce the latest docs page above, only out of date stuff. Limiting search to www.boost.org didn't get 1.44 docs (only misleading ref to 1.38). This may be why there are so many questions from puzzled users on this list? Is there anything we can do to make Google work better for us? Paul --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow(a)hetp.u-net.com

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[regex] Boost.Regex + ICU vs. standalone ICU
by AJG 27 Sep '10

27 Sep '10

Hi there, Is there a document out there describing any substantial differences (in particular, w.r.t. semantics and correctness) between using Boost.Regex with ICU support baked in as opposed to ICU's built-in RegexMatcher/RegexPattern classes? I do realize, for example, that the former's API has a 'modern C++' style, whereas the latter is modeled on Java's -- but these differences seem to be mostly cosmetic. Is there anything else I should be aware of before deciding to use one or the other -- performance, functionality, ease-of-use, etc.? Thanks! PS: It doesn't look like xpressive has Unicode support yet, which is why I'm not considering it, but I'd love to know if this impression is false or soon-to-be false.

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How to get the temporary directory ?
by Timothy Madden 27 Sep '10

27 Sep '10

Hello The new boost::filesystem::unique_path in V3 filesystem is great, but is there any way to also get the temporary directory ? A function that would return ::GetTempPath() on Windows systems and something like /tmp or /var/tmp on POSIX systems ? Or is there some portable way to do this already ? Thank you, Timothy Madden

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