September 2012 - Boost-users - lists.preview.boost.org

boost replacement for std::ostringstream
by Chris Stankevitz 07 Sep '12

07 Sep '12

Hello, Does boost provide a replacement for std::ostringstream? If so, can you please tell me the name so I can read the docs on it? The first thing I am going to read is whether or not such a best would provide "reserve". I would like to do this: //----- std::ostringstream Stream; // Stream.reserve(99999); // error: std::ostringstream does not provide reserve Stream.write(pBuffer, 99999); //----- Thank you, Chris

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Boost.Hash and enums
by Filip Konvička 07 Sep '12

07 Sep '12

Hi, In Boost 1.51, it looks to me like boost::hash_value no longer knows how to handle enums anymore. Is the following the right way to tell it to treat enums like ints? #if (BOOST_VERSION >= 105100) // Boost 1.51.0+ namespace boost { /// Enable hashing of enums. template<typename E> size_t hash_value( E const e, typename std::enable_if<std::is_enum<E>::value, E>::type def = static_cast<E>(0)) { return hash_value((int)e); } } #endif Is enum hashing support going to be added to the library in the future? Thanks, Filip

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Re: [Boost-users] Why is there so much co-dependency in Boost? Is there anything to be done about it?
by steve＠parisgroup.net 07 Sep '12

07 Sep '12

Hi again, I'm the original poster that started this thread. WOW! Thanks for all of the great responses. I apologize for posting this message and then getting called away on a business trip. It is only just now that I'm getting back to see what kind of response I got, and I'm thrilled. I'm happy to see that a number of folks involved with Boost see this issue as a significant problem, if only to certain types of companies. APOLOGY: I must apologize for a small mistake in my numbers, that might be somewhat important to someone. I managed to reverse the counts for the "Smart Ptr" and "String Algo" libraries. I remember thinking it kinda strange that one referenced more modules but the other referenced more lines. So it's really true that "String Algo" causes 382 files to be read, while "Smart Ptr" causes only 180 to be read. Sorry about that. I've taken a first pass through all the responses, and rather than respond to each of them individually, I'll offer some more information here and attempt to address address some of the questions that have been pointed back to me. 1) How did I get these numbers. Give some examples. Here's one of the places I'd love to be shown to be wrong. If my numbers are inflated, my sales job to my boss will be that much easier. So by all means, someone correct me if my approach is unsound. What I did was very simple. All I did was compile a very simple program and have g++ give me a list of all of the headers it read during the compilation, excluding system headers. This is done using the following line from my test Makefiles: $(CXX) $(CPPFLAGS) $(CXXFLAGS) -c $< 2> /dev/null -MM > headers.lst Here's the test for SmartPtr: #include <iostream> #include <boost/smart_ptr.hpp> using namespace std; int main(int argc, char* argv[]) { return 0; } This simple test produces a file named headers.lst with 180 unique header paths in it, all starting with "boost/". Discovering the modules used by each module took a few hours of fairly tedious labor, where I sorted and then grouped each list of headers, where each group consisted of headers coming from the same module. 2) Here are the specific module dependencies: Any: "base", Config, Exception, MPL, Preprocessor, Static Assert, Type Traits, Utility Filesystem: "base", Config, Exception, Functional, Integer, Iterators, MPL, Preprocessor, Smart Ptr, Static Assert, Type Traits, Utility SmartPtr "base", Config, Exception, MPL, Preprocessor, Static Assert, Type Traits, Utility StringAlgo: "base", Bind, Compatibility, Concept Check, Config, Exception, Function, Integer, Iterators, MPL, Preprocessor, Range, Static Assert, String Algo, Type Traits, Utility 3) In response to the suggestion to not use the convenience headers, like say "smart_ptr.hpp" as apposed to a header for an individual header type. It's bad enough to tell my programmers they can only use certain Boost modules. To tell them that they can only use certain parts of certain Boost modules just gets to be too much. Plus, I can see eventually using most, if not all of the functionality of the SmartPtr module. The same can be said for the other modules I'm interested in. If I have to run to my boss every time I want to use one new particular feature from a Boost module, it's not worth the effort. Nor would it be worth the overhead of figuring out how to police such a level of code use. So for better or worse, my consideration of the use of Boost has to be on a Module by Module basis. 4) In response to "the license says that it's free to use, and the copyright holders have agreed to that license, so everything is fine". That's not true in the legal world. Neither the license nor any statements made by the person stating a copyright mean anything if that person somehow, if intentionally or unintentionally, included some bit of someone else's code in what they are calling their own. If the original writer of the code can prove original authorship of the code, nothing done without THAT PERSON'S GRANT OF LICENSE means anything. That original author owns all rights to the use of that code, and can dictate how it can and cannot be used. It is this issue that concerns companies like mine. 5) In response to "Who cares how much code there is. How does one "vet" a piece of code, regardless of how much of it there is". It is not hard to look at 100 or 1000 lines of code in a few files and say "there's nothing novel here". If the code is all written to do one basic thing or set of things in a direct way, it's pretty easy to believe that a single or a few individuals wrote the code. And, if the claimed authorship is invalid, real damages would easy to justify as being minimal, given the very limited scope of what the code is capable of doing. It's also much easier to feel comfortable in the fact that many other developers are using these 1000 lines of code in their commercial products and haven't yet been sued over the use of some portion of it. And if/when one wants to upgrade to the next version of a module consisting of 1000 lines of code, it's pretty easy to see what was added/removed. But in the case of boost, with hundreds and possibly thousands (with fuller adoption) of individual files involved, consisting of tens to hundreds of thousands of lines of code, you can't have any idea what you've got In fact, you can feel fairly confident that all of those lines of code are NOT NECESSARY in the basic sense to the benefit you wish to gain from the module in question. So you have to ask yourself "what more does all this code do?", and you certainly can't read and understand the purpose of every line of such a quantity of code to answer that question And the fact that there's so much of it, leads one to wonder "what novel things might be going on in that code to require so much of it"? I mean, 384 header files being read for a Smart Ptr library is pretty darn "novel" in and of itself. Finally, there's mere statistics involved. If 1000 lines of code opens a company to a certain amount of negative exposure, 100,000 lines of code, one might argue, opens the company to 100 times as much exposure. 6) And...I'm not sure this question was asked specifically, but I'll ask it myself..."what are you so worried about". Here's an example of what we're worried about.... Say we develop a tool for Disney to use on one of its feature length films. A month before the premier date of the film, someone takes Disney to court and claims that one of their production tools, the one we wrote, contains code that was stolen from them. Disney asks us to come to court to defend our use of that code. In the case of 1000 lines, we can say exactly what we did to vet the use of the code, and state exactly what that code does not just for us but for anyone who might use it, pointing out that each of those users has a very clear idea of what the code does, what it's worth to them, and why they considered the copyright given by the supposed author to be valid. For 100,000 lines of code we say, well the 1% of the code we use kinda/sort works by doing this, but it does that by going off and using bits and pieces of all these other files, and frankly, we couldn't take the time to understand what all that code is for, and therefore can not possibly have understood that the code contained something novel that might have been misrepresented as to its authorship for reason of personal gain on the part of the offending copyright grantor. In the first case, maybe the judge puts some value on the 1000 lines of code, and because it's Disney, that number gets multiplied by 10X. It's still a small amount of money for Disney, so they pay the money and just decide never to do business with us again. In the second case, the judge says "wow, there's a lot of code here. This is going to take a lot of time to work out the ramifications of, and to put a dollar amount on" and files an injunction against Disney releasing their film. This costs Disney many millions of dollars on everything they've set in motion in order to release the film, that will now all be wasted money. Disney sues us for all of that money. We, as a very small software company, talk to our lawyer, who tells us our best bet is to fold the company and go find jobs working for Google. 7) Use a more modern C++ Some of our customers are in the Operating System Stone Age. For example, I often develop on Fedora, but my code has to be able to compile and run on Red Hat 5. AND, we are often told exactly what compiler to use, and that compiler sometimes not open source, and in a few cases no longer supported. So solving these issues with newer compilers is not an option. 8) Conclusion So, it DOES MATTER, IN A BIG WAY how much code I have to bring into my project's codebase to get SmartPtr capabilities. And even if it turned out that it didn't, my boss doesn't consider it worth the risk to make that call. He'd rather hire another programmer just to write a SmartPtr library, so that our project can stay on schedule and he can sleep at night, knowing his company isn't going to some day go "poof" due to a relaxed approach to using Open Source. Some of our customers don't allow their engineering departments any access to code on the internet for this very reason. There are firewalls designed solely to look for and disallow anything that looks like significant code or other data from coming into the company walls. We have to justify our use of each specific piece of Open Source to EACH OF THESE COMPANIES before we can begin to supply them with anything. So another big issue for us is that as soon as we say "We use Boost", we are dismissed from consideration for a project. I bet this happens all the time. Thanks All for all the interesting and valuable discourse! Take care! Steve PS) My company DOES already use the Boost Smart Ptr library. However, it uses a much earlier version of the library, one that depends on just a dozen or so headers. So I guess at one point individual Boost modules were more separable. Or maybe it was just generally smaller back when that module was adopted. So we DO already have and use Boost Smart Ptrs...we just don't have all the nifty new features in the latest and greatest, the most important of which is the ability to not require that the pointed to class be defined wherever a Smart Ptr is instantiated. I'm dying for that feature.

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[mpi] Linking with MPICH2 under Cygwin
by Murphy, John T. 07 Sep '12

07 Sep '12

Hello all, I recently posted two messages concerning linking boost.mpi with MPICH2 under Cygwin. For the list archives, the solution to this problem was to make sure that the boost libraries were created using the link=static and runtime-link=static boost build options, which creates libraries appropriate for static linking (and marked with a -s infix). When linked statically to the MPICH libraries and the appropriate boost libraries my code can execute correctly. Best, John -- John T. Murphy Computational Postdoctoral Fellow Decision and Information Sciences and Argonne Leadership Computing Facility Argonne National Laboratory jtmurphy(a)anl.gov

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boost::asio buffer questions, and boost::bind question
by Littlefield, Tyler 07 Sep '12

07 Sep '12

Hello: I had a couple of questions. I'm really confused about how the buffers in boost::asio work. I'm using async_read_until, and it wants a streambuf. so I looked at that, and it's a typedef for basic_streambuf. so I'm looking at how to set one of these up, and stackoverflow shows something like: boost::asio::streambuf streamBuffer; boost::asio::streambuf::mutable_buffers_type mutableBuffer = streamBuffer.prepare(max_length); so I'm curious what the mutable buffer is, and how it wraps around streambuf. I'm also curious how people generally handle buffers in their classes. I have a Session class, which will hold a buffer of data to be read, so that when I call HandleRead, it can just look at that buffer for the last line read in. Do I need to store a mutable_buffer and a streambuf? Or is the streambuf ok (and can I pull the data out of it somehow). Also, in that article it shows that it wraps the mutableBuffer in a boost::asio::buffer(what's the point in that?) Finally, my boost::bind question. I was curious how that worked out. When I use _1, _2 as placeholders, does the templating get substituted in somehow? Does it somehow construct an object that just has a () operator to take arguments? Also, if I wanted to write something to let me pull in the errors like placeholders, how do placeholders work/get translated out? Thanks, -- Take care, Ty http://tds-solutions.net The aspen project: a barebones light-weight mud engine: http://code.google.com/p/aspenmud He that will not reason is a bigot; he that cannot reason is a fool; he that dares not reason is a slave.

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Boost.Thread win32 mutex implementations
by Collin Dauphinee 06 Sep '12

06 Sep '12

I was just looking at the win32 implementations of the various Boost.Thread mutex classes (specifically basic_recursive_mutex). I was surprised to see that they use WaitForSingleObject internally, rather than a CRITICAL_SECTION. I've found mentions that it originally used a CRITICAL_SECTION, but no explanation of why it was changed. It seems to me, personally, that the hybrid locking functionality of the CRITICAL_SECTION implementation would be more desirable than the WaitForSingleObject implementation in most use cases. Is there a reason for this choice? At first glance, it looks like it was just done to re-use code from the timed_mutex, which can't (easily) be implemented with CRITICAL_SECTION. Regards, Collin

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Re: [Boost-users] Accessing MSM attribute under specific conditions causes non-compile
by Chiem Whua Ma 06 Sep '12

06 Sep '12

Thank you for your help! I see now that it's not that that the sub-machine is a state of the main machine, but ANY time you have an entry action performed directly from the machine level the fsm is reported as a state and not as an fsm. This isn't a problem since I know this is happening, but perhaps it might be possible to change this so fsm entry actions put the fsm in the fsm parameter slot? What is fsm equal to when an entry action is performed? Here's some code that shows exactly what can be set where and when for anyone else who is trying to figure this out... #include <vector> #include <iostream> #include <boost/msm/back/state_machine.hpp> #include <boost/msm/front/euml/euml.hpp> using namespace std; using namespace boost::msm::front::euml; namespace msm = boost::msm; namespace MSM_A // Concrete FSM implementation { BOOST_MSM_EUML_DECLARE_ATTRIBUTE(int, borrowedBuffer_attribute); BOOST_MSM_EUML_DECLARE_ATTRIBUTE(int, someother_Attribute); BOOST_MSM_EUML_ACTION(someAction) { template <class Event,class FSM,class STATE> void operator()(Event const& event,FSM& , STATE& state) { std::cout<<"Doing someAction."<<std::endl; state.get_attribute(borrowedBuffer_attribute)=1; } }; BOOST_MSM_EUML_ACTION(someOtherAction) { template <class Event,class FSM ,class STATE> void operator()(Event const& event,FSM& fsm, STATE& state) { std::cout<<"Doing someOtherAction."<<std::endl; fsm.get_attribute(borrowedBuffer_attribute)=1; state.get_attribute(someother_Attribute)=1; } }; BOOST_MSM_EUML_EVENT(someevent) BOOST_MSM_EUML_STATE((someOtherAction, no_action, attributes_<<someother_Attribute), someStateA) BOOST_MSM_EUML_STATE((no_action), someStateB) BOOST_MSM_EUML_TRANSITION_TABLE(( someStateA + someevent == someStateB ),transition_table) BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, init_ << someStateA, someAction, // <-------------------- ACTION IS AN ENTRY ACTION no_action, attributes_ << borrowedBuffer_attribute, configure_ << no_configure_ ), MSM_A_frontEnd) //fsm name typedef msm::back::state_machine<MSM_A_frontEnd> MSM_A_player; } namespace MSM_B // Concrete FSM implementation { ::MSM_A::MSM_A_player subMachine; BOOST_MSM_EUML_DECLARE_ATTRIBUTE(int, rootFSM_attribute); BOOST_MSM_EUML_DECLARE_ATTRIBUTE(int, rootstate_attribute); BOOST_MSM_EUML_EVENT(someEvent) BOOST_MSM_EUML_ACTION(rootFSM_action) { template <class Event,class FSM,class STATE> void operator()(Event const& event,FSM& , STATE& state) { std::cout<<"Doing rootFSM_action."<<std::endl; state.get_attribute(rootFSM_attribute)=1; } }; BOOST_MSM_EUML_ACTION(another_rootFSM_action) { template <class Event,class FSM,class STATE> void operator()(Event const& event,FSM& fsm , STATE& state) { std::cout<<"Doing another_rootFSM_action."<<std::endl; fsm.get_attribute(rootFSM_attribute)=1; state.get_attribute(rootstate_attribute)=1; } }; BOOST_MSM_EUML_STATE((another_rootFSM_action, no_action, attributes_<<rootstate_attribute), someState) BOOST_MSM_EUML_TRANSITION_TABLE(( someState + someEvent == someEvent ), transition_table) BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, //STT init_ << subMachine << someState, rootFSM_action, // Entry no_action, // Exit attributes_ << rootFSM_attribute, // Attributes configure_ << no_configure_ ), MSM_B_frontEnd) //fsm name typedef msm::back::state_machine<MSM_B_frontEnd> MSM_B_player; } int main() { std::cout<<"Making player."<<std::endl; MSM_B::MSM_B_player player; std::cout<<"Starting player."<<std::endl; player.start(); std::cin.ignore(1); return 0; }

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Why is there so much co-dependency in Boost? Is there anything to be done about it?
by steve＠parisgroup.net 06 Sep '12

06 Sep '12

Greetings, As a veteran C++ programmer, I've been an admirer of the Boost library for many years. I've used it at a number of companies I've worked for, especially the SmartPtr library. Right now I'm working for a company that worries a lot about negative exposure to Open Source software issues such as questions that might arise about authorship, copyright or even patent issues. The company does allow the use of Open Source software, but it requires that each piece of code that is brought in first be justified and vetted. Unfortunately, I'm finding this to be a nearly impossible task when I look at the amount of code that must be compiled to use the Boost modules I'm interested in. I've done a study and written some tools, to determine just how many Boost header files must be included to use some of the Boost modules. The numbers are staggering: Any: 79 FileSystem: 276 Smart Ptr: 382 String Algo: 180 I went on and did a tally of which modules these header files came from. Here are the counts for how many other Boost modules each of these modules depends upon: Any: 8 FileSystem: 13 SmartPtr: 8 String Algo: 15 Given these numbers, I think I have to abandon any thoughts of using Boost within my current company. There's no way I'm going to get approval to bring so much code into our work just to get a SmartPtr or FIleSystem library. This is unfortunate, because due to Boost's existence there doesn't seem to be much work going on out there to offer lighter weight alternatives. I'm writing this request in the hopes that there's something I'm missing here, and that someone can point out my folly. Is there a way to utilize any of these Boost modules in such a way that they do not require the inclusion of so much code? If not, does anyone have any suggestions as to how to make this fly with my boss? Has this issue come up before and been considered by the Boost designers? I find the issue baffling. TIA for any help or insight anyone can provide. Steve

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[mpi] broadcast performance
by Brian Budge 06 Sep '12

06 Sep '12

Hi all - I need some advice for using the broadcast function of boost::mpi. We have a large buffer (sometimes gigabytes) that we need to get to all child nodes. We currently use boost::serialization with a binary archive to write the data into a std::vector<char>. Then we send that data across, and deserialize. The data is sent with MPI_Bcast. I've started testing with similar functionality using boost::mpi::broadcast to handle serialization and deserialization. Tracing through the code, it seems that the data is sent to all the child nodes via isend. Is there something I can do to ensure that Bcast will be used instead? If I only have a couple of nodes, the former is fine, but with more nodes, the MPI implementation of Bcast may do a better job (logarithmic or even constant time with the number of nodes). What are the suggestions for getting fast broadcast in this case? I don't think that using skeletons will help, since each instance of the broadcast will have unique data with potentially different layouts. Thanks, Brian

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serialisation use of asserts versus throw ?
by Avi Bahra 06 Sep '12

06 Sep '12

This is question about use of asserts in boost serialisation. As a program migrates from one release to another the api changes. This is expected. In my case I have client/server that uses boost serialisation. I was expecting an throw due to the incompatibility not a an assert. The assert crashes my client, giving no chance for recovery, and informing the user that they are using previous out of date release/server. In may case: boost_iarchive.cpp inline const basic_pointer_iserializer * 399 basic_iarchive_impl::load_pointer( 400 basic_iarchive &ar, 401 void * & t, 402 const basic_pointer_iserializer * bpis_ptr, 403 const basic_pointer_iserializer * (*finder)( 404 const boost::serialization::extended_type_info & type_ 405 ) 406 407 ){ ..... 436 BOOST_ASSERT(NULL != bpis_ptr); 437 class_id_type new_cid = register_type(bpis_ptr->get_basic_serializer()); 438 int i = cid; 439 cobject_id_vector[i].bpis_ptr = bpis_ptr; 440 BOOST_ASSERT(new_cid == cid); // yikes How do people get round this issue, where old and new release of software need to co-exist ? Would it be possible to use a #define to configure use of asserts or throw ? Any help apperciated . Best regards, Ta, Avi

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Boost.Variant: Infinite recursion in constructor
by Markus Lenger 06 Sep '12

06 Sep '12

Hi! I face a problem using Boost.Variant 1.48 under Windows with Cygwin and g++ (GCC) 4.5.3. The following code crashes due to infinite recursion in the constructor of a_t: #include <boost/variant.hpp> #include <iostream> struct a_t { boost::variant< boost::recursive_wrapper<a_t>,int > child; }; int main() { a_t a; std::cout << "OK" << std::endl; return 0; } If I change the type of "child" to "boost::variant< int, boost::recursive_wrapper<a_t> >" (I just swapped the template parameters) the program prints "OK". Any ideas?

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boost dijkstra : retrieve the whole path
by Viviane Parent 06 Sep '12

06 Sep '12

Hello people I'm stubbling on a very stupid problem I think, but I can't find any hint about it. I'm using the boost algorithm dijkstra_shortest_path and I simply want to know how to retrieve all the steps the algo goes through for the shortest path found. To illustrate : I'm glad to know that to go from A to Z, the minimal cost is 26, but I would like also to know that this path goes from A to B then from B to C etc. I used the example http://www.boost.org/doc/libs/1_51 [...] ample.cpp<http://www.boost.org/doc/libs/1_51_0/libs/graph/example/dijkstra-example.cp…> So I ended up with dijkstra_shortest_paths(g, s, &p[0], &d[0], weightmap, indexmap, std::less<int>(), closed_plus<int>(), (std::numeric_limits<int>::max)(), 0,default_dijkstra_visitor()); (I use Visual) Is the info I need somewhere in the visitor, or something ? Thanks for any help you can provide, Sorry for my crappy english V

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Strange linker error
by John M. Dlugosz 06 Sep '12

06 Sep '12

On a Mac, I'm getting a strange linker error, Duplicate symbol typeinfo name for boost::tag_original_exception_type* (in two .o files). Now I only see that name used once in the boost source code, in exception/detail/exception_ptr.hpp, and don't see how it could mean different things in different translation units. Any clue what that's about? —John

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Using a binomial_heap with indirect_cmp
by David Doria 05 Sep '12

05 Sep '12

I am trying to keep a heap sorted by values in a property map. I tried the code below, but the compiler does not like my arguments to the heap constructor (PriorityQueueType pq(indirectComparison);). According to the documentation (http://www.boost.org/doc/libs/1_51_0/doc/html/boost/heap/binomial_heap.html) there is a constructor: explicit binomial_heap(value_compare const & = value_compare()); that takes a value_compare, which I was thinking would of type IndirectComparisonType that I provided (I don't really understand the optional template arguments and the base_maker::compare_argument type of things)? Here is the indirect_cmp doc for reference: http://www.boost.org/doc/libs/1_51_0/boost/pending/indirect_cmp.hpp #include <boost/heap/binomial_heap.hpp> #include <boost/pending/indirect_cmp.hpp> #include <boost/array.hpp> #include <boost/graph/grid_graph.hpp> #include <iostream> int main(int, char*[]) { // Construct a graph boost::array<std::size_t, 2> lengths = { { 2,2 } }; typedef boost::grid_graph<2> GraphType; GraphType graph(lengths); typedef boost::graph_traits<GraphType>::vertex_descriptor Vertex; typedef boost::property_map<GraphType, boost::vertex_index_t>::const_type GridIndexMapType; GridIndexMapType gridIndexMap(get(boost::vertex_index, graph)); // Construct a property map typedef boost::vector_property_map<float, GridIndexMapType> PriorityMapType; PriorityMapType priorityMap(gridIndexMap); // Construct the indirect comparison functor typedef boost::indirect_cmp<PriorityMapType, std::less<float> > IndirectComparisonType; IndirectComparisonType indirectComparison(priorityMap); // Construct the queue typedef int ValueType; typedef boost::heap::binomial_heap<ValueType, boost::heap::stable<false>, IndirectComparisonType> PriorityQueueType; PriorityQueueType pq(indirectComparison); return 0; } Does anyone know how to provide this indirect comparison functor to the queue properly? Thanks, David

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Problems in boost/mpl/aux_/template_arity.hpp when BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS is defined on g++ 4.6.3 and boost 1.50
by Alach 05 Sep '12

05 Sep '12

Hi, Please help. I have encountered a problem on gcc 4.6.3 and boost 1.50 when trying to compile my library with extensive usage of boost::mpl and boost::fusion on gcc. It was required to enable customization of the number of template arguments handled by boost::fusion and boost::mpl containers and mpl meta functions. Not surprisingly the code compiles fine in visual studio 2010. whole code can be found here: svn checkout svn://svn.code.sf.net/p/d-injection/code-0/trunk This is how I have altered template arguments count: #define FUSION_MAX_VECTOR_SIZE DI_MAX_NUM_INJECTIONS #define FUSION_MAX_VECTOR_SIZE DI_MAX_NUM_INJECTIONS #define BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS #define BOOST_MPL_LIMIT_VECTOR_SIZE DI_MAX_NUM_INJECTIONS #define BOOST_MPL_LIMIT_SET_SIZE DI_MAX_NUM_INJECTIONS #define BOOST_MPL_LIMIT_METAFUNCTION_ARITY DI_MAX_NUM_INJECTIONS #include <boost/fusion/include/as_vector.hpp> #include <boost/fusion/include/as_set.hpp> #include <boost/fusion/adapted/mpl.hpp> #include <boost/fusion/include/mpl.hpp> #include <boost/fusion/include/for_each.hpp> #include <boost/fusion/include/at_key.hpp> #include <boost/mpl/vector.hpp> #include <boost/mpl/remove.hpp> #include <boost/mpl/inserter.hpp> #include <boost/mpl/transform.hpp> #include <boost/mpl/insert.hpp> #include <boost/mpl/count.hpp> #include <boost/mpl/copy.hpp> #include <boost/mpl/set.hpp> #include <boost/mpl/inherit.hpp> #include <boost/mpl/joint_view.hpp> #include <boost/mpl/contains.hpp> #include <boost/mpl/size.hpp> #undef FUSION_MAX_VECTOR_SIZE #undef FUSION_MAX_SET_SIZE #undef BOOST_MPL_LIMIT_VECTOR_SIZE #undef BOOST_MPL_LIMIT_SET_SIZE #undef BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS #undef BOOST_MPL_LIMIT_METAFUNCTION_ARITY And I get this error: In file included from ../../libraries/boost_1_50_0/boost/mpl/aux_/full_lambda.hpp:29:0, from ../../libraries/boost_1_50_0/boost/mpl/lambda.hpp:22, from ../../libraries/boost_1_50_0/boost/mpl/apply.hpp:25, from ../../libraries/boost_1_50_0/boost/mpl/aux_/fold_impl.hpp:19, from ../../libraries/boost_1_50_0/boost/mpl/fold.hpp:20, from ../../libraries/boost_1_50_0/boost/fusion/sequence/intrinsic/detail/segmented_size.hpp:12, from ../../libraries/boost_1_50_0/boost/fusion/sequence/intrinsic/size.hpp:16, from ../../libraries/boost_1_50_0/boost/fusion/view/joint_view/joint_view.hpp:15, from ../../libraries/boost_1_50_0/boost/fusion/algorithm/transformation/push_back.hpp:11, from ../../libraries/boost_1_50_0/boost/fusion/view/iterator_range/detail/segmented_iterator_range.hpp:19, from ../../libraries/boost_1_50_0/boost/fusion/view/iterator_range/detail/segments_impl.hpp:13, from ../../libraries/boost_1_50_0/boost/fusion/view/iterator_range/iterator_range.hpp:21, from ../../libraries/boost_1_50_0/boost/fusion/view/iterator_range.hpp:10, from ../../libraries/boost_1_50_0/boost/fusion/sequence/intrinsic/detail/segmented_begin.hpp:12, from ../../libraries/boost_1_50_0/boost/fusion/sequence/intrinsic/begin.hpp:17, from ../../libraries/boost_1_50_0/boost/fusion/container/vector/vector10.hpp:15, from ../../libraries/boost_1_50_0/boost/fusion/container/vector/vector_fwd.hpp:14, from ../../libraries/boost_1_50_0/boost/fusion/container/vector/vector.hpp:10, from ../../libraries/boost_1_50_0/boost/fusion/container/vector/detail/as_vector.hpp:18, from ../../libraries/boost_1_50_0/boost/fusion/container/vector/convert.hpp:10, from ../../libraries/boost_1_50_0/boost/fusion/include/as_vector.hpp:10, from ./di/detail/variadics.hpp:42, from ./di/subject.hpp:10, from test/abstract_builder_should.hpp:11, from test/main.cpp:6: ../../libraries/boost_1_50_0/boost/mpl/aux_/template_arity.hpp:86:1: error: macro "BOOST_PP_TUPLE_ELEM_E_2" requires 2 arguments, but only 1 given ../../libraries/boost_1_50_0/boost/mpl/aux_/template_arity.hpp:86:1: error: macro "BOOST_PP_SEQ_ELEM_III" requires 2 arguments, but only 1 given ../../libraries/boost_1_50_0/boost/mpl/aux_/template_arity.hpp:86:1: error: macro "BOOST_PP_SEQ_ELEM_III" requires 2 arguments, but only 1 given There are more of course, but the consensus is that all errors are somewhat connected to BOOST_PP_ macros. I've tried to find the reason, but with no luck. Thank you in advance, Adam. -- View this message in context: http://boost.2283326.n4.nabble.com/Problems-in-boost-mpl-aux-template-arity… Sent from the Boost - Users mailing list archive at Nabble.com.

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[mpi] linking MPI with MPICH2 under Cygwin
by Murphy, John T. 05 Sep '12

05 Sep '12

Hello, I'm getting a very consistent problem trying to link with the Boost.MPI library and MPICH2 under Cygwin. What seems to be happening is that the libboost_mpi library that is created contains redundant copies of elements from the MPI libraries. For example: It is possible to add debugging code to MPICH2 source code, build MPICH2, build Boost's mpi library against this, then compile, link, and run an executable, with the result that the debugging code is output from the MPICH functions. Then it is possible to modify the MPICH debugging code and rebuild MPICH2, but leave Boost's mpi library so that it is _not_ rebuilt. When the executable is rebuilt and linked to the boost and MPICH libraries, the output indicates that some of the old versions of the debugging code are still being used while other functions have the new code. The error I am getting is 'Attempting to use an MPI routine before initializing MPICH'. My debugging suggests that during execution there are two distinct copies of the MPICH flag that indicates that MPICH has been initialized; one of these shows that the MPI_Init initialization has been run but the other does not. Additionally, an MPI program that contains no reference to boost and that compiles and runs cleanly when linked only with the MPICH libraries will crash with the same error if the linker is instructed to link against the boost mpi library, even though nothing in the boost namespace appears in the code. Has anyone seen this, or have a solution? The issue seems to be something that is happening with linking while the Boost.mpi library is being built, part of which is being done by bjam (aka b2). Is it possible to specify how boost's mpi library will be built and linked against the MPICH libraries, and if so is there a strategy I can use to avoid the problems I am having? I'm using Boost 1.48 for compatibility with other code we're using. I have the same code built and running on other systems; the error seems to be specific to the Cygwin environment. Thanks, John -- John T. Murphy Computational Postdoctoral Fellow Decision and Information Sciences and Argonne Leadership Computing Facility Argonne National Laboratory jtmurphy(a)anl.gov

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BGL: d_ary_heap_indirect duplicated values
by David Doria 05 Sep '12

05 Sep '12

I am using a d_ary_heap_indirect as a priority queue using a property map to store the priorities. However, I when I change the values in the priority property map and push vertices that are already in the queue into the queue again, it results in kind of an invalid state where the vertex appears in the queue twice at different positions. Here is a demo: http://programmingexamples.net/wiki/CPP/Boost/BGL/IndirectPriorityQueue It simply sets random priority values for every vertex, and pushes them all into the queue. It then does exactly the same thing again. You can see that some vertices appear twice in the queue at different positions. For example, vertex (3,0) occurs at position 0 in the queue, and again at position 6. Of course the priority values that are output are the same because the demo simply outputs the values that are currently in the priority property map, but I guess I would expect the two instances of a vertex to appear at back-to-back positions in the queue (as it should have used their current value to sort the queue)? Is there a way to replace a vertex in the queue when it is pushed instead of adding a second one? (like an std::set instead of the current behavior which is like std::multiset)? Thanks, David

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asio: question regarding design
by Goran 05 Sep '12

05 Sep '12

Hi all, I wanna change the design of some async client (code at end of this message) towards something like "run as a server and pull a message from another server". The so called "another server" will be my master server in future. At the moment I'm taking some example from asio's documentation: http://www.boost.org/doc/libs/1_46_1/doc/html/boost_asio/tutorial/tutdaytim… The async client is derived from another example of asio's documentation: http://www.boost.org/doc/libs/1_46_1/doc/html/boost_asio/example/http/clien… My simple question is: How would you change the code below to run in a loop and pulls 'let's say' every second a message from master server? Thanks a lot! #include <iostream> #include <istream> #include <ostream> #include <string> #include <boost/asio.hpp> #include <boost/bind.hpp> using boost::asio::ip::tcp; class client { public: client(boost::asio::io_service& io_service, const std::string& server, const std::string& port) : resolver_(io_service), socket_(io_service) { // Start an asynchronous resolve to translate the server and service names // into a list of endpoints. tcp::resolver::query query(server, port); resolver_.async_resolve(query, boost::bind(&client::handle_resolve, this, boost::asio::placeholders::error, boost::asio::placeholders::iterator)); } private: void handle_resolve(const boost::system::error_code& err, tcp::resolver::iterator endpoint_iterator) { if (!err) { // Attempt a connection to each endpoint in the list until we // successfully establish a connection. tcp::endpoint endpoint = *endpoint_iterator; socket_.async_connect(endpoint, boost::bind(&client::handle_connect, this, boost::asio::placeholders::error)); } else { std::cout << "Error: " << err.message() << "\n"; } } void handle_connect(const boost::system::error_code& err) { if (!err) { // The connection was successful. Read the response. boost::asio::async_read(socket_, response_, boost::bind(&client::handle_response, this)); } else if (err != boost::asio::error::eof) { std::cout << "Error: " << err.message() << "\n"; } } void handle_response() { if (response_.size() > 0) std::cout << "Response: " << &response_; else std::cout << "Response is empty." << std::endl; } tcp::resolver resolver_; tcp::socket socket_; boost::asio::streambuf request_; boost::asio::streambuf response_; }; int main(int argc, char* argv[]) { try { if (argc != 3) { std::cout << "Usage: async_client <server> <port>\n"; std::cout << "Example:\n"; std::cout << " async_client localhost 2020\n"; return 1; } boost::asio::io_service io_service; client c(io_service, argv[1], argv[2]); io_service.run(); } catch (std::exception& e) { std::cout << "Exception: " << e.what() << "\n"; } return 0; }

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Re: [Boost-users] compilation problems with thread/chrono & boost 1.51 & HPUX
by Avi Bahra 05 Sep '12

05 Sep '12

>Le 04/09/12 11:44, Avi Bahra a ?crit : >>>> On 3.9.2012. 10:26, Avi Bahra wrote: >>>>> Can any one suggest *any* hacks/workarounds that gets me pass these errors. >>>>> Is it possible to use gcc on HPUX with boost 1.51 ? >>>> The docs for boost thread 1.51 say this: >>>> >>>> Boost.Thread uses by default Boost.Chrono for the time related >>>> functions. For backward compatibility and also for compilers that don't >>>> work well with Boost.Chrono the user can define >>>> BOOST_THREAD_DONT_USE_CHRONO. If BOOST_THREAD_DONT_USE_SYSTEM is defined >>>> then BOOST_THREAD_DONT_USE_CHRONO is defined implicitly. >>>> >>>> BOOST_THREAD_USES_CHRONO is defined when Boost.Thread uses Boost.Chrono. >> I have already tried BOOST_THREAD_DONT_USE_CHRONO and it has no effect. >> It appears that some of headers files are not guarded with this. >> >> In my case >> $BOOST_ROOT/boost/chrono/system_clocks.hpp >This evidently should not be included. Could you point from where it is >included? libs/chrono/src/chrono.cpp fails to compile with errors in system_clocks.hpp and overflow_helpers.hpp >> $BOOST_ROOT/boost/ratio/detail/overflow_helpers.hpp >This evidently should not be included. Could you point from where it is >included? libs/chrono/src/chrono.cpp fails to compile with errors in system_clocks.hpp and overflow_helpers.hpp libs/chrono/src/process_cpu_clocks.cpp fails to compile with error in overflow_helpers.hpp >> $BOOST_ROOT/boost/thread/future.hpp >Could you point where in this file the compiler fails? >> do not compile, >> "libs/thread/src/future.cpp" >> >> Also Is it possible to make a request to change: >> >> $BOOST_ROOT/boost/thread/future.hpp >> >> line:603 >> for(count_type i=0;i<count;++i) >> { >> #if defined __DECCXX || defined __SUNPRO_CC >> locks[i]=boost::unique_lock<boost::mutex>(futures[i].future_->mutex).move(); >> #else >> locks[i]=boost::unique_lock<boost::mutex>(futures[i].future_->mutex); >> #endif >> } >> >> T0: >> >> for(count_type i=0;i<count;++i) >> { >> #if defined __DECCXX || defined __SUNPRO_CC || defined __hpux >> locks[i]=boost::unique_lock<boost::mutex>(futures[i].future_->mutex).move(); >> #else >> locks[i]=boost::unique_lock<boost::mutex>(futures[i].future_->mutex); >> #endif >> } >> >Please could you create a ticket for that? created ticket 7329. It should be noted that there also numerous warnings in compiling file libs/chrono/src/process_cpu_clocks.cpp i.e "./boost/chrono/detail/inlined/posix/process_cpu_clocks.hpp", line 118: warning #2940-D: missing return statement at end of non-void function "boost::chrono::process_real_cpu_clock::now(boost::system::error_code &)" } "./boost/chrono/detail/inlined/posix/process_cpu_clocks.hpp", line 194: warning #2940-D: missing return statement at end of non-void function "boost::chrono::process_user_cpu_clock::now(boost::system::error_code &)" } "./boost/chrono/detail/inlined/posix/process_cpu_clocks.hpp", line 271: warning #2940-D: missing return statement at end of non-void function "boost::chrono::process_system_cpu_clock::now(boost::system::error_code &)" } "./boost/chrono/detail/inlined/posix/process_cpu_clocks.hpp", line 350: warning #2940-D: missing return statement at end of non-void function "boost::chrono::process_cpu_clock::now(boost::system::error_code &)" } These could easily be removed by simple restructure of the code. Best regards, Ta, Avi

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Re: [Boost-users] [boost] [Review.Coroutine] Some comments
by Oliver Kowalke 05 Sep '12

05 Sep '12

> * I don't know if showing the signature in the documentation will be > more informative. OK > * Could you add the following noexcept specifier? OK > * As the template class Allocator is not used to allocate internal > memory of the coroutine class. Could the Allocator parameter be renamed > StackAllocator? OK > * Could you add an standard Allocator parameter as e.g. the one of > packaged_task? > > C++ International Standard > > * I understand that the Boost.Context Allocator parameter is part od the > class, as context is a low-level class, but coroutine is more high > level. Is there a possibility to type erase the StackAllocator (and > preceding Allocator) template parameter, as packaged_task do? This will > allow to store coroutines (and generators) with the same signature in a > container even if they don't share the Allocator. You mean coroutine would have two allocators - one for allocating internal memory and one for allocating the stack? Removing the StackAllocator from the template arguments of coroutine should not that problem (would require an internal pointer to an internal interface - maybe detail::context_exec is a candidate). I've some concerns about having two allocator objects in coroutine's ctor . > * Parameters and move semantics. Could the signature parameters be > rvalue references? > > R operator()(A0 a0, ..., A9 a9); Hmmm - this would require a second version of opertor() and all arguments are moveable?! R operator()(BOOST_RV_REF( A0) a0, ..., BOOST_RV_REF( A)) a9); > I'm asking this because I think that Boost.Tuple has not implemented yet > move semantics. don't know - would that be an issue > * What about moving some of the coroutine/generator optional parameters > to a coro::attributes class > > std::size_t size = ctx::default_stacksize(), > flag_unwind_t do_unwind = stack_unwind, > bool preserve_fpu = true, instead of passing those threee params as args to coroutine ctor? good point > * Usually (at least in the C++ standard) a function doesn't throws > because of its preconditions are not satisfied. then assert? pre-conditions should be checked but how should I react if I get garbage from the user? > This should be coherent with > > > |Result operator()()| > > Preconditions: > > |*this| is not a /not-a-generator/, |! is_complete()|. > > which doesn't throws any specific exception if the preconditions are not > satisfied. does an assert - OK the I'll replace throwing excpetions be assertions > Documentation > ========= > > coroutine.html > > s/it can migrated between threads/it can migrate between threads/ OK > s/yield_return/yield_break/ > > * documentation for the following constructor is missing in the reference > > template< typename Fn > > coroutine( Fn && fn, > std::size_t size = ctx::default_stacksize(), > flag_unwind_t do_unwind = stack_unwind, > bool preserve_fpu = true, > Allocator alloc = Allocator() ); OK I think it will be easy to incorporate your suggestions - but during the boost.context review I was told not to modify the reviewd library (if the review is still on-going). regards, Oliver

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can different versions of boost coexist in an executable?
by Nathan Ridge 05 Sep '12

05 Sep '12

Hello, I am developing a C++ library, which I distribute in binary form as a static library. The implementation of my library uses Boost, but the interface does not, so I completely shield my users from the Boost dependency by linking the Boost object files that my implementation requires into the static library. Suppose a client of my library uses Boost in their own code. When they link their executable, the linker now sees two copies of some Boost libraries: the copy in my static library, and their own copy that they are linking. It seems that the linker only keeps one of the two and discards the other. If the Boost version that I linked into my static library is different from the Boost version my client uses, then one of my code and their code will be linked to a different version of Boost that the one it was compiled against, leading to a crash. I suppose one way to rectify this problem would be for me to document what version of Boost libraries I compiled and linked against, and require that if my clients use Boost themselves, they use the same version. However, I dislike this solution for two reasons: 1) It exposes my library's dependence on Boost, which was meant to be an implementation detail. 2) It limits my clients to using a particular version of Boost. They may have good reasons for using an older (or newer!) version instead. I would much prefer if the linker kept both copies of the Boost libraries in the executable, and each piece of code (mine and my client's) used whichever version of the libraries it was compiled against. Can this be accomplished? Thanks, Nate

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[fusion] Wrapping a Fusion sequence
by Agustín K-ballo Bergé 04 Sep '12

04 Sep '12

I'm looking for a way to create a Fusion sequence wrapper that is itself a Fusion sequence and forwards all 'calls' to its wrapped sequence. Something in the lines of template< typename Sequence > struct sequence_wrapper { explicit sequence_wrapper( Sequence const& s ) : seq( s ){} Sequence seq; }; where sequence_wrapper< Sequence > is a Fusion sequence as well, and works just as Sequence would. The reason I need this is that I have several functions that operate on Fusion sequences (where all elements satisfy some special requirements), and I would like to add some syntax sugar for which I need a custom type to add overloaded operators to. I do not need the result of operations on a sequence_wrapper to return a sequence_wrapper as well, only the syntax sugar related calls would return a (manually) wrapped sequence. For instance, appending elements to a sequence using the comma operator (somewhat of a Boost.Assign for Fusion sequences): template< typename Sequence, typename T > sequence_wrapper< typename boost::fusion::result_of::push_back< Sequence const& , T >::type > operator,( Sequence const& seq, T const& v ) { return sequence_wrapper< typename boost::fusion::result_of::push_back< Sequence const& , T >::type >( boost::fusion::push_back( seq, v ) ) ; } What would be the best way to achieve this (if it is indeed supported by the library)? I'm particularly trying to avoid creating a Fusion sequence from scratch, as I would like to use whatever sequence is returned by Fusion operations. Would inheritance + specialization of `tag_of` to return the tag of the wrapped sequence just work? Or will I need to define a tag of my own and implement all required functions to just forward the call? Thank you in advance. Agustín K-ballo Bergé.- http://fusionfenix.com

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Trying to compile and use boost on proprietary complier similar to MPICH2 CXX
by Chris 04 Sep '12

04 Sep '12

Hi all, hope this is the right list for my question. So here it goes: When it try to use boost using a proprietary MPIC++ compiler I have no control over, I get the following errors: In file included from ../boost_1_43_0/boost/thread/detail/platform.hpp:17, from ../boost_1_43_0/boost/thread/thread.hpp:12, from ../boost_1_43_0/boost/thread.hpp:13, from test.cpp:37: ../boost_1_43_0/boost/config/requires_threads.hpp:47:5: error: #error "Compiler threading support is not turned on. Please set the correct command line options for threading: -pthread (Linux), -pthreads (Solaris) or -mthreads (Mingw32)" In file included from ../boost_1_43_0/boost/thread/thread.hpp:12, from ../boost_1_43_0/boost/thread.hpp:13, from test.cpp:37: ../boost_1_43_0/boost/thread/detail/platform.hpp:67:9: error: #error "Sorry, no boost threads are available for this platform." In file included from ../boost_1_43_0/boost/thread.hpp:13, from test.cpp:37: ../boost_1_43_0/boost/thread/thread.hpp:19:2: error: #error "Boost threads unavailable on this platform" The thing is, when I use the standard mpicxx from MPICH2, things work out fine. I'm now trying to find out if the problem lies in the complier, or if I simply did not compile and bootstrap boost properly. What I did when building boost is the following: ./bootstrap.sh --with-libraries=date_time,filesystem,serialization,iostreams,system,thread,mpi ./bjam cxxflags="-O2" release threading=multi link=static After bootstrap, I tried to manually edit the user-config.jam to add "using mpi ;" and explicitly added the path to the compiler, but this all did not change the above mentioned error when I try to compile my code that uses boost. Is this enough information for you to judge if I might have overlooked something when building boost? Many thanks, Chris

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filesystem directory_iterator run-time error during construction after upgrading to OSX Lion
by Martin Searancke 04 Sep '12

04 Sep '12

I have just upgraded my Mac to Lion and code that worked fine under snow leopard is giving me a run-time exception when constructing a directory_iterator. The error I am getting is "malloc: pointer being freed was not allocated" The line in question that raises this error is: for ( directory_iterator itr( my_path ); itr != end_itr; ++itr ) taken directly from the example and working fine under windows. This is version 1.49 installed with MacPorts. Is this a known problem? I found some vague references to a similar problem in an earlier version of boost but no solution. I have confirmed that I only have 1 copy of the headers and libs on the system and in the correct path. The date stamp on the files matches the last time I did a macports update so this should be the matching library for the header. Please note that I am a real novice to Mac development and have only just started porting code from windows for less than a month. Thanks in advance, Martin

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Re: [Boost-users] compilation problems with thread/chrono & boost 1.51 & HPUX
by Avi Bahra 04 Sep '12

04 Sep '12

>>On 3.9.2012. 10:26, Avi Bahra wrote: >>> Can any one suggest *any* hacks/workarounds that gets me pass these errors. >>> Is it possible to use gcc on HPUX with boost 1.51 ? >> >>The docs for boost thread 1.51 say this: >> >>Boost.Thread uses by default Boost.Chrono for the time related >>functions. For backward compatibility and also for compilers that don't >>work well with Boost.Chrono the user can define >>BOOST_THREAD_DONT_USE_CHRONO. If BOOST_THREAD_DONT_USE_SYSTEM is defined >>then BOOST_THREAD_DONT_USE_CHRONO is defined implicitly. >> >>BOOST_THREAD_USES_CHRONO is defined when Boost.Thread uses Boost.Chrono. I have already tried BOOST_THREAD_DONT_USE_CHRONO and it has no effect. It appears that some of headers files are not guarded with this. In my case $BOOST_ROOT/boost/chrono/system_clocks.hpp $BOOST_ROOT/boost/ratio/detail/overflow_helpers.hpp $BOOST_ROOT/boost/thread/future.hpp do not compile, Also Is it possible to make a request to change: $BOOST_ROOT/boost/thread/future.hpp line:603 for(count_type i=0;i<count;++i) { #if defined __DECCXX || defined __SUNPRO_CC locks[i]=boost::unique_lock<boost::mutex>(futures[i].future_->mutex).move(); #else locks[i]=boost::unique_lock<boost::mutex>(futures[i].future_->mutex); #endif } T0: for(count_type i=0;i<count;++i) { #if defined __DECCXX || defined __SUNPRO_CC || defined __hpux locks[i]=boost::unique_lock<boost::mutex>(futures[i].future_->mutex).move(); #else locks[i]=boost::unique_lock<boost::mutex>(futures[i].future_->mutex); #endif } Best regards, Ta, Avi

2 1