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Pattern issue with boost::regex
by Tal Shnaiderman 24 Oct '14

24 Oct '14

Hi All, I have a question regarding boost::regex pattern recognition and groups I created the following code, in it i created a pattern and a string to match: 1 2 3 4 5 6 p = "((a b (f+\\.))d d(\\3))"; str="a b ffff.d dfff."; boost::regex pattern(p, boost::regex::icase&boost::regex::extended &~boost::regex::no_bk_refs); bool match = boost::regex_match(str, pattern); cout << str << ((match)?"-Pattern is legal":"-Pattern is illegal" )<< endl; Pattern is illegal I'm saw that my result is 'Pattern is illegal' because the group \\3 that refers to (f+\\.) isn't equal to it. if I change the input to str="a b ffff.d dffff."; The pattern is legal. In other words my original plan was to use the \\3 instead of writing the pattern; p = "((a b (f+\\.))d d(f+\\.))"; But I can see that in the original pattern it simply expect the same output to reappear Is there a way I can use the group naming not to copy the (f+\\.) group? Thanks, I hope my Q is clear since I'm new to the regex topic.

3 2

cross compile boost for arm TRY2 (Possibly solved)
by John Davis 24 Oct '14

24 Oct '14

Hello Here is a more succient attempt at building boost with a cross compiler. It appears to work. I'm not certain if it works at this point though. Please take a look and comment. Here is the script: --------------------------------------------------------------- #!/bin/bash # edit /opt/xxx/yyy/boost/boost_1_51_0/tools/build/v2/user-config.jam to add the following line # using gcc : 4.3arm : arm-linux-gnueabi-g++ : <architecture>arm <target-os>linux ; # Later we modify path, make sure our path does not use the cross compiler at beginning export PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/opt/java6/bin:/opt/java6/db/bin:/opt/java6/jre/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl # In this stage, we are using the host compiler. # setup env variable for $BOOST_DIR # I'm not sure if this is being used, but set it just in case. export BOOST_ROOT=/opt/xxx/yyy/boost/boost_1_51_0 # this is run from $BOOST_DIR/tools/build/v2 aka /opt/xxx/yyy/boost/boost_1_51_0/tools/build/v2 # in this case, I do not think you invoke the cross compiler. I think at this point, you are building # code for the host development machine. ./bootstrap.sh --with-toolset=gcc # setup path so that gcc from cross compiler is first in the path # also specify cross_compiler env variable in case its used. # # this will find the cross compiler for those who dont use the prefix, ie. gcc export PATH=/opt/arm/usr/local/arm-linux-gnueabi/bin:$PATH # this will find the cross compiler for those who use the prefix, ie. arm-linux-gnueabi-gcc export PATH=/opt/arm/usr/local/bin:$PATH # this will set the cross compiler prefix for those who use it export CROSS_COMPILE=arm-linux-gnueabi- # build boost.build so that we can build boost or are we building boost at this point? # # WARNING!!! # Specify an install directory so that it doesn't put the results in /usr/local/bin. # Even if you dont specify install as an option to ./b2 it will attempt to copy files to /usr/bin # in the following step! # # /opt/xxx/boost is where we want results. Our code will this dir in order to use boost. # /opt/xxx/yyy/boost/boost_1_51_0 is the top of the boost src. We are building beneath there. ./b2 --toolset=gcc-4.3arm --prefix=/opt/xxx/boost # at this point, we have the cross compiler in our path first. We are good to go for building our code using boost # with the cross compiler. -------------------------- -- John F. Davis 6 Kandes Court Durham, NC 27713 919-888-8358 独树一帜

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[Log] record_ostream too restrictive due to non-copyability, non-assignability?
by Latimerius 23 Oct '14

23 Oct '14

Hello, I'm trying to migrate from an existing solution to Boost.Log. So far I've been able to emulate all important features of the existing library - except one. The existing library supported submitting a log message in multiple statements. This is useful when the message being composed has conditional parts, when a part of it is composed in a loop or even a different function, something like this: auto logmsg = log (Channel::CORE, Severity::DEBUG); logmsg << "unconditional part"; if (condition) logmsg << " conditional part"; for (auto element : container) logmsg << element; logging_subroutine (logmsg); logmsg << endmsg; To that end I extracted a structure from the manual_logging() function from the Boost.Log documentation to hold the state of the message being composed: struct log_msg_state { my_logger & logger; logging::record rec; logging::record_ostream strm; ... <constructor & destructor definition> ... }; Having done this, I can emulate most of the above example fairly easily by defining a bunch of operator<<() overloads for the log_msg_state. However, I've been struggling with record_ostream. It was a bit of a challenge even to initialise it in the constructor - we can't use the initialiser list as we have to make sure first that our logging::record is valid. On the other hand, in the ctor body when the check can be performed, it's too late as record_ostream has already been constructed already and as it turns out, you can't do much with a constructed instance - no usual stuff like if (rec) strm = logging::record_ostream (rec); works! Fortunately, I've been able to hack around it like this: if (rec) new (&strm) logging::record_ostream (rec); Not pretty but has been working well so far! However, I've failed to find a solution for returning my log_msg_state (and thus record_ostream) from a function. The non-copyability, non-assignability, non-moveability are always getting in the way. (Note also that I do NOT want to hold a pointer to record_ostream in my log_msg_state and allocate it dynamically - that would certainly make things easier but I don't want to penalise each and every log message with a dynamic allocation for no good reason.) Could someone please advise me how to get the functionality I need, a solution or a work-around at least? Thanks in advance pvl

1 0

unused parameter warning
by Kevin Molcard 23 Oct '14

23 Oct '14

Hi all, in some boost libraries I am using, there are compilation warnings complaining about unused parameter. For instance: boost/signals2/detail/auto_buffer.hpp:102:45: warning: unused parameter 'size' I'd like to get rid of the warnings. What is the best way to proceed? Should I send a merge request in github or something else? Thanks in advance Kevin

1 0

using boost in cross compiler environment. intel host and arm target
by John Davis 22 Oct '14

22 Oct '14

Hello I have some code for arm which I would like to use with boost. The boost libraries I am interested in are not header only and thus require building. I have downloaded the boost tarfile and I have read the following two webpages relative but I am still confused. Here is a summary of the two urls and where I am confused. http://www.boost.org/doc/libs/1_56_0/more/getting_started/ This url has the following procedure which seems to use the host default compiler to build boost. Easy Method for Building and Installing Boost Binary Libraries. step 1: $ cd $BOOST_DIR step 2: $ ./bootstrap.sh --help step 3: $ ./bootstrap.sh --prefix=path/to/installation/prefix ( Other docs specify for this step: $ ./b2 --build-dir=/tmp/build-boost toolset=gcc stage (optional --build-type=complete) Also says that --stagedir=/path/to/install/special/stage/target/library/binaries I'm not certain what the stage components are or what the stage part is. ) $ ./b2 install “This will leave Boost binaries in the lib/ subdir of the installation prefix.” The only customization mentioned here is for where you want your results to be placed. step 4: Add path/to/installation to my $PATH environment variable. http://www.boost.org/doc/libs/1_51_0/doc/html/bbv2/tasks.html#bbv2.tasks.cr… The section is on common tasks for boost build, in particular in the section is task on cross compilation. Boost.Build supports cross compilation with gcc toolset. When using gcc, you first need to specify your cross compiler in user-config.jam for example: using gcc : arm : arm-none-linux-gnueabi-g++; This looks good, i'm thinking I need to edit a user-config.jam file. After that, if the host and target os are the same, for example linux, you can just repeat this compiler version to be used: b2 toolset=gcc-arm Regarding the user-config.jam file. These are the notes I took while reading: http://www.boost.org/doc/libs/1_51_0/doc/html/bbv2/overview.html#bbv2.overv… On startup, boost.build searches and reads two config files: site-config.jam and user-config.jam. Alternatively, the docs say you can edit the one at the top of the boost.build directory. In my case, I believe that would be $BOOST_DIR/tools/build/v2 directory rather than $BOOST_DIR. This directory has five .jam files: boost-build.jam, bootstrap.jam, build-system.jam, Jamroot.jam, site-config.jam and user-config.jam. Then I started thinking maybe editing this file will build boost.build for running on arm. I don't want to run boost.build on arm. I want it to use the cross compiler to build boost so that the libs will work with code that runs on arm. Summary, this is what I think I need to do. Please correct me where I am wrong. 1. using the tarfile I've downloaded, copy the $BOOST_DIR/tools/build/v2/user-config.jam file to my /home/davis directory. 2. edit the ~/user-config.jam file (I wish I could put this file in the $BOOST_DIR tree rather than my home dir) to use the cross compilers I have in my /opt/arm directory. 3. With the /opt/arm/ compiler directory in my path and in the $BOOST_DIR/tools/build/v2 directory issue the commands to build boost 3.a. $ ./bootstrap.sh --prefix=path/to/installation/prefix --with-toolset=gcc-arm 3.b this should add a b2 program in the path/to/installation/prefix dir. /path/to/installation/prefix will actually be /opt/arm/boot.build. This should have the boost build tool I build that runs on intel but is set to build boost for arm. 4. Change directory to $BOOST_DIR 4.a $ /path/to/installation/prefix/b2 --build-dir=/tmp/build-boost toolset=gcc-arm or literally /opt/arm/boot.build/bin?/b2 -build-dir=/tmp/build-boost toolset=gcc-arm 4.c $ /path/to/installtion/prefix/b2 install -- John F. Davis 6 Kandes Court Durham, NC 27713 919-888-8358 独树一帜

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Flyweight: wrapping shared_ptr
by Akim Demaille 22 Oct '14

22 Oct '14

Hi all, I'd like to add hash-consing on top of my hiearchy-based AST implementation, which uses shared_ptr (I'm in C++11) to guarantee value semantics (the pointee is const). Below is a tiny version that would help me see if using Boost.Flyweight is adequate. It works, but it is not transparent, because I have to explicitly call '.get()' on my flyweights to deference to the pointers. So for instance my code reads: size_t hash() const { size_t res = 0; hash_combine(res, boost::hash_value(op)); hash_combine(res, l.get()->hash()); hash_combine(res, r.get()->hash()); return res; } where I expect to have l->hash(), not l.get()->hash(). I have tried deriving from flyweight to add an operator->, but it fails horribly. I realize that it is suboptimal to use flyweight on top of shared_ptr, as I get two reference counters. Yet this change is less invasive than migrating my AST hierarchy to using variants as is done in the example of the documentation. What would be the right approach? Thanks a lot.

3 11

Problem with bundled BGL properties
by alev mutlu 21 Oct '14

21 Oct '14

Hi all, I am new to BGL and the followings are snippets from my code. When I compile my code I get the following error. Any suggestions, error: no match for ‘operator=’ in ‘city_name.boost::vec_adj_list_vertex_property_map<Graph, GraphPtr, ValueType, Reference, Tag>::operator[] [with Graph = boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, relation, boost::property<boost::edge_name_t, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::no_property>, boost::no_property, boost::listS>, GraphPtr = boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, relation, boost::property<boost::edge_name_t, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::no_property>, boost::no_property, boost::listS>*, ValueType = boost::detail::error_property_not_found, Reference = boost::detail::error_property_not_found&, Tag = boost::vertex_name_t](v1) = r’ /home1/mutlu/boost/include/boost-1_37/boost/pending/detail/property.hpp:21: note: candidates are: boost::detail::error_property_not_found& boost::detail::error_property_not_found::operator=(const boost::detail::error_property_not_found&) struct argument{ int is_variable; string value; }; struct relation{ string relation_name; vector<argument> arguments; }; typedef property<edge_name_t, std::string> EdgeNameProperty; typedef adjacency_list<vecS, vecS, directedS, relation, EdgeNameProperty> Graph; int main(){ Graph g; property_map<Graph, vertex_name_t>::type city_name = get(vertex_name, g); property_map<Graph, edge_name_t>::type edge_value = get(edge_name, g); typedef graph_traits<Graph>::vertex_descriptor Vertex; typedef graph_traits<Graph>::edge_descriptor Edge; Vertex v1; v1 = add_vertex(g); city_name[v1]= r; } error: no match for ‘operator=’ in ‘city_name.boost::vec_adj_list_vertex_property_map<Graph, GraphPtr, ValueType, Reference, Tag>::operator[] [with Graph = boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, relation, boost::property<boost::edge_name_t, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::no_property>, boost::no_property, boost::listS>, GraphPtr = boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, relation, boost::property<boost::edge_name_t, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::no_property>, boost::no_property, boost::listS>*, ValueType = boost::detail::error_property_not_found, Reference = boost::detail::error_property_not_found&, Tag = boost::vertex_name_t](v1) = r’ /home1/mutlu/boost/include/boost-1_37/boost/pending/detail/property.hpp:21: note: candidates are: boost::detail::error_property_not_found& boost::detail::error_property_not_found::operator=(const boost::detail::error_property_not_found&)

1 0

1.57.0 beta 1 release candidates available for testing
by Marshall Clow 21 Oct '14

21 Oct '14

Release candidate files for 1.57.0 beta 1 are available at http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: MD5 (boost_1_57_0_b1_rc1.7z) = 8633fbf5ebb7eaabcb0f309c14646ae3 MD5 (boost_1_57_0_b1_rc1.tar.bz2) = 8e76f98146793f0fbd2492a9151c405b MD5 (boost_1_57_0_b1_rc1.tar.gz) = d41ff3ffb36ac84ff5bf34f799308907 MD5 (boost_1_57_0_b1_rc1.zip) = 8a844dc36284247b2e936f2120e118b2 Thanks! -- The release managers

7 17

1.57.0 beta 1 is now available
by Marshall Clow 20 Oct '14

20 Oct '14

Boost release 1.57.0 beta 1 is now available from SourceForge See http://sourceforge.net/projects/boost/files/boost-binaries/1.57.0.beta.1/ This release contains no new libraries. For details of what's in the release, see http://www.boost.org/users/history/version_1_57_0.html. Note that the links to files on this web page are for the final release - use the SourceForge link above to get the beta files. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team P.S. There are a couple of known problems with this beta: * There are problems building with MSVC 8.0 * There are some problems with range/detail/any_iterator.hpp. These will be fixed before the release.

1 0

Boost 1.56 with QT creator, “LNK1104: cannot open file 'libboost_unit_test_framework-vc100-mt-gd-1_56.lib'”
by Kavita 20 Oct '14

20 Oct '14

Hello, I am working on a project of boost unit testing framework using QT creator. I have written a small test program and trying to link "libboost_unit_test_framework-vc100-mt-gd-1_56.lib". This library is present at specified path. But program fails to compile giving said linking error. I searched on net and found that, error should go with "#define BOOST_ALL_NO_LIB". But then, I am getting below error: main.obj:-1: error: LNK2019: unresolved external symbol "class boost::unit_test::test_suite * __cdecl init_unit_test_suite(int,char * * const)" (?init_unit_test_suite@@YAPAVtest_suite@unit_test@boost@@HQAPAD@Z) referenced in function _main The above function is a part of "libboost_unit_test_framework-vc100-mt-gd-1_56.lib". I have written same unit tests using VS 2010 and with the same boost libraries. The program worked properly with expected behavior. What could be possibly going wrong with the usage of boost on QT ? Please help ! -Thanks

6 6

[Log] Writing empty messages with the attributes as the actual payload
by Scott Mueller 17 Oct '14

17 Oct '14

Hello Boost.Users! I'm trying to integrate Boost logging with an existing message infrastructure. In this infrastructure, I have an existing schema that looks like this: Severity Timestamp Process source (much like "channel") Process component (more like a "sub-channel") Message ID A vector of arguments The message is rendered by looking up the message ID to receive the following information: formatting string ("This is an example of %1 message type. The arguments can look like this %4, 3, 2"), the expected argument types which are potentially convertible if the underlying type is different, and so on. I guess what I'm asking is whether or not a logging source can accept the arguments as defined by a compile-time defined schema in the form of attributes with an empty message. Can the logging core route message records defined in this way properly? Is such a thing supported? I'm in the process of writing something up to do this, but I'd like to know in advance whether or not "empty" messages with a bunch of attributes set can get routed to supported sinks. Thanks in advance for your help! Best regards, M. Scott Mueller

1 0

boost serialisation 1.56, why does library version change, when no change in library ?
by avib369 . 16 Oct '14

16 Oct '14

At boost 1.53 the library version was 10, however at boost 1.56 it has jumped to 11. I have not seen any documentation/release notes about boost serialisation changes. What has changed in boost serialisation to merit this change ? The documentation in $BOOST_ROOT/libs/serialization/basic_archive.cpp describes the changes to boost library version, however it does *not* describe why it jumped from 10 -> 11. Any help appreciated. Ta, Avi

2 1

[thread] linux.hpp, BOOST_HAS_PTHREAD_YIELD, BOOST_HAS_SCHED_YIELD
by Rob Conde 16 Oct '14

16 Oct '14

Using boost 1.55, Ubuntu 12.04, gcc 4.6 I'm building boost on linux using the lsb sdk. I was getting the failure (paraphrased): pthread_yield not declared in libs/thread/src/thread.cpp 513 The documentation for pthread_yield (http://man7.org/linux/man-pages/man3/pthread_yield.3.html) says: This call is nonstandard, but present on several other systems. Use the standardized sched_yield(2)<http://man7.org/linux/man-pages/man2/sched_yield.2.html> instead. If I change boost/config/platform/linux.hpp to define BOOST_HAS_SCHED_YIELD instead of BOOST_HAS_PTHREAD_YIELD Then sched_yield is used instead and the build finishes properly. I'm posting this for two reasons: 1. To help others running into the same issue 2. To question whether linux.hpp should be updated officially as I did above 3. If not, why Thanks, Rob Conde

1 0

Boost.Python: Polymorphism downcasting
by Christoff Kok 16 Oct '14

16 Oct '14

Hi, I have a list of base classes in C++, I want to access them in Python as a list of their derived most classes. Is there a build in means to cater for this in Boost.Python? I've made an example the problem I ma facing: // ------------------------------- Code ----------------------------------// #include<memory> #include<iostream> #include<vector> namespace boost { template<class T> T* get_pointer(std::shared_ptr<T>& p){ return p.get(); }} struct Vehicle{ virtual ~Vehicle(){} friend bool operator==(const Vehicle& lhs, const Vehicle& rhs) { return true; }}; struct Boat: public Vehicle{ virtual ~Boat(){} friend bool operator==(const Boat& lhs, const Boat& rhs) { return true; } char const* testBoatSpecificMethod() { return "Floating."; } }; struct Truck: public Vehicle{ virtual ~Truck(){} friend bool operator==(const Truck& lhs, const Truck& rhs) { return true; } char const* testTruckSpecificMethod() { return "Trucking."; } }; class Garage { public: Garage() {}; ~Garage() {}; char const* test() { std::string temp = "Vehicle List Size: " + std::to_string(m_VehicleList.size()); return temp.c_str(); } friend bool operator==(const Garage& lhs, const Garage& rhs) { return true; } std::vector<Vehicle>& vehicleList() { return m_VehicleList; } private: std::vector<Vehicle> m_VehicleList; }; #include <boost/python.hpp> #include <boost/python/suite/indexing/vector_indexing_suite.hpp> BOOST_PYTHON_MODULE(garage_ext) { using namespace boost::python; class_<Garage>("Garage") .def("test", &Garage::test) .def("vehicleList", &Garage::vehicleList, return_internal_reference<1>()); class_<Vehicle,std::shared_ptr<Vehicle>>("Vehicle"); class_<Boat,std::shared_ptr<Boat>,bases<Vehicle>>("Boat") .def("testBoatSpecificMethod", &Boat::testBoatSpecificMethod); class_<Truck,std::shared_ptr<Truck>,bases<Vehicle>>("Truck") .def("testTruckSpecificMethod", &Truck::testTruckSpecificMethod); implicitly_convertible<std::shared_ptr<Boat>,std::shared_ptr<Vehicle>>(); implicitly_convertible<std::shared_ptr<Truck>,std::shared_ptr<Vehicle>>(); class_<std::vector<Vehicle> >("stl_vector_Vehicle") .def(vector_indexing_suite<std::vector<Vehicle> >()); } // --------------------------- Test Script -------------------------------// import garage_ext g = garage_ext.Garage() l = g.vehicleList() l.append(garage_ext.Boat()) print "Expecting a Boat object:" print str(l[0]) print g.vehicleList()[0].testBoatSpecificMethod() garage_ext.f2("Done.") // ------------------------------ Output ---------------------------------// Expecting a Boat object <garage_ext.Vehicle object at 0x7fb17a3bfb50> Traceback (most recent call last): File "test_garage.py", line 7, in <module> print g.vehicleList()[0].testBoatSpecificMethod() AttributeError: *'Vehicle' object has no attribute 'testBoatSpecificMethod'* *'Vehicle' object has no attribute 'testBoatSpecificMethod'* Here I want Vehicle to be a Boat object. If there is not a build in or recommended/known Boost.Python means to handle this problem, I'm thinking of wrapping the list (Lots of accessors to be wrapped in my library.) with a get accessor returning a boost::python::list, storing the derived most types. Getting the derived most type possibly by calling overriden 'getAsDerivedClass' method. I would like to avoid this. I dislike having to add python usage specific methods to the library, for our design and vision values / reasons. Kind Regards, Christoff

1 1

BGL - maximum_adjacency_search - assignedVertices
by Adam Celick 14 Oct '14

14 Oct '14

I was looking at the implementation of maximum_adjacency_search algorithm and got confused by the assignedVertices local variable. It is defined as a set of vertex descriptors and is being iterated over inside the main loop (lines 168-184) but it is never inserted into. So the for loop will always skip. It looks to me as if that part of the code can be eliminated. Am I missing something? Thanks, Adam

1 0

Generating kuratowski subgraph with external edge index map
by Amir Hassan 13 Oct '14

13 Oct '14

Hi! I have a graph which i test for planarity and in case the test fails i want to generate the kuratowski subgraph. I have code that used to compile with boost graph 1.36 but doesn't with 1.56. I guess the problem has to do with the type of the edge index map. you can find code and error messages here: http://stackoverflow.com/questions/26346343/c-boost-graph-generating-kurato… Help is greatly appreciated! greets, amir

1 0

[interprocess 1.42] Copy multiple variables into shared memory
by Michael Behnke 13 Oct '14

13 Oct '14

Hello, I'm trying to write multiple variables one by one into a mapped_region, but somehow I fail. Here is the Code I worked on so far: boost::interprocess::shared_memory_object shm_obj(boost::interprocess::open_or_create, "Test", boost::interprocess::read_write); shm_obj.truncate(1000); boost::interprocess::mapped_region region(shm_obj, boost::interprocess::read_write, 0, 0); uint32_t size = 33; uint32_t type = 666; std::string data("I'm a Test!"); uint32_t* start_ptr_int = &(static_cast<uint32_t*> (region.get_address())[0]); std::memcpy(start_ptr_int, &size, sizeof (uint32_t)); start_ptr_int = &(static_cast<uint32_t*> (region.get_address())[4]); std::memcpy(start_ptr_int, &type, sizeof (uint32_t)); char* start_ptr_char = &(static_cast<char*> (region.get_address())[8]); std::memcpy(start_ptr_char, data.c_str(), data.length()); uint32_t sizeOfData; std::memcpy(&sizeOfData, &(static_cast<uint32_t*> (region.get_address())[0]), sizeof (uint32_t)); uint32_t typeOfData; std::memcpy(&typeOfData, &(static_cast<uint32_t*> (region.get_address())[4]), 4); char* revData = new char[sizeOfData]; std::memcpy(revData, &(static_cast<char*> (region.get_address())[sizeof (uint32_t) * 2]), sizeOfData); First I write an uint32_t into the region at index 0. Afterwards, I'm writing another uint32_t at position 4 (assuming the first uint32_t took the bytes 0 - 3). Last I write a string into the region, at index 8. Reading the first uint32_t again from shared memory works fine, as does reading the string (the last variable). But if I try to read the second variable (uint32_t) the data is not what I expected. I know that the problem is memcpy, somehow my syntax does not work. Unfortunately I could not find a matching example, cause mostly memset is used to explain the functionality of boost::mapped_region. I have to write lots of data into shared memory (structured like size1|type1|data1|...|sizeN|typeN|dataN) but still can't figure out how to do this the right way. Any suggestions are greatly appreciated. Kind regards Michael Behnke -- Bachelorand ________________________________________________________ ADITION technologies AG Schwarzwaldstraße 78b 79117 Freiburg http://www.adition.com T +49 / (0)761 / 88147 - 30 F +49 / (0)761 / 88147 - 77 SUPPORT +49 / (0)1805 - ADITION (Festnetzpreis 14 ct/min; Mobilfunkpreise maximal 42 ct/min) Eingetragen beim Amtsgericht Düsseldorf unter HRB 54076 Vorstände: Andreas Kleiser, Jörg Klekamp, Marcus Schlüter Aufsichtsratsvorsitzender: Joachim Schneidmadl UStIDNr.: DE 218 858 434

1 0

Boost Locale – accessing ICU functions directly
by Caroline Beltran 10 Oct '14

10 Oct '14

I recently began using Boost Locale traversing and boundary analysis of Unicode strings. I’ve used some of the features available for case conversion, i.e.: to_upper(), which appears to wrap ICU’s toUpper() function. I didn’t find Boost Locale wrappers for other ICU functions such as u_isalpha() or u_isalnum(). How can I these ICU functions? Thank you!

1 0

Are shared memory files distributable?
by Rajalakshmi Iyer 10 Oct '14

10 Oct '14

Hello, Is it possible to create a shared memory file using Boost Interprocess (with STL containers) and distribute it to several machines for reading and modifying independently? Thanks Raj -- @BlisMedia <http://twitter.com/BlisMedia> www.blismedia.com <http://blismedia.com> This email and any attachments to it may be confidential and are intended solely for the use of the individual to whom it is addressed. Any views or opinions expressed are solely those of the author and do not necessarily represent those of BlisMedia Ltd, a company registered in England and Wales with registered number 06455773. Its registered office is 3rd Floor, 101 New Cavendish St, London, W1W 6XH, United Kingdom. If you are not the intended recipient of this email, you must neither take any action based upon its contents, nor copy or show it to anyone. Please contact the sender if you believe you have received this email in error.

2 1

[make_shared] How to use boost::make_shared with more than 9 arguments
by dariomt＠gmail.com 10 Oct '14

10 Oct '14

I could patch my local copy with several more overloads (I need up to 12 parameters) but, is there a better way? I cannot change the constructor of the class to group parameters (as recommended in StackOverflow). Of course this is for C++03 Regards

2 1

Re: [Boost-users] Flyweight: wrapping shared_ptr
by Joaquin M Lopez Munoz 10 Oct '14

10 Oct '14

> De: Boost-users [mailto:boost-users-bounces@lists.boost.org] > En nombre de Akim Demaille > Enviado el: martes, 07 de octubre de 2014 18:27 > Para: Boost Users List > Asunto: Re: [Boost-users] Flyweight: wrapping shared_ptr > > Le 7 oct. 2014 à 18:18, Joaquín Mª López Muñoz <joaquin(a)tid.es> a écrit : > > > An alternative would be to use some sort of cloning smart pointer to > > spare the reference count, but it's not clear to me this would be > > faster than > > shared_ptr: > > > > * element exists: shared_ptr creation is slower than clone_ptr > > creation > > * element does not exist: shared_ptr creation and copy is probably > > faster than clone_ptr creation and cloning. > > Yes, indeed. A slightly smarter approach involves a cloning class that accepts a const Base& and does only clone on copy, thus avoiding dynamic memory allocation when the element already exists. This can be nicely wrapped up as follows: template<typename Base> class poly_holder { public: poly_holder(const Base& x):p(&x),dlt(false){} poly_holder(const poly_holder& x):p(x.p->clone()),dlt(true){} poly_holder& operator=(const poly_holder& x) { Base* q=x.p->clone(); if(dlt)delete p; p=q; dlt=true; return *this; } ~poly_holder(){if(dlt)delete p;} operator const Base&()const {return *p;} private: const Base* p; bool dlt; }; template<typename Base> class poly_flyweight:public boost::flyweight<poly_holder<Base>> { public: using super=boost::flyweight<poly_holder<Base>>; using super::super; const Base& operator*() const{return base();} const Base* operator->()const{return &base();} private: const Base& base()const{return this->get();} }; template<typename Base> std::size_t hash_value(const poly_flyweight<Base>& x) { return boost::hash<const Base*>()(&*x); } template<typename Base> bool operator==( const poly_flyweight<Base>& l,const poly_flyweight<Base>& r) { return static_cast<boost::flyweight<poly_holder<Base>>>(l)== static_cast<boost::flyweight<poly_holder<Base>>>(r); } template<typename Base> bool operator!=( const poly_flyweight<Base>& l,const poly_flyweight<Base>& r) { return !(l==r); } I've rewritten your test case to take advantage of this poly_flyweight thing, cleaning up some unnecessary hash and operator== overloads along the way and without resorting to the intermediate Exp_ type; see: http://coliru.stacked-crooked.com/a/76e87531b65d44f9 > Is there anyway Flyweight could have supported the operator-> natively? > It seems that with some SFINAE under the hood, it would work, don't you think? Yep, that would be possible, the only reason I didn't do it is to not clutter the interface. Also, some std classes such as (C++17) std::optional implement operator* differently, without the extra dereference required by smart pointer semantics. Joaquín M López Muñoz Telefónica

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Boost.Geometry, probable bug in point_on_surface
by Petr Doubrava 10 Oct '14

10 Oct '14

#include <boost/geometry.hpp> #include <boost/geometry/geometries/point_xy.hpp> #include <boost/geometry/geometries/polygon.hpp> void test_point_on_surface() { typedef boost::geometry::model::point<double, 2, boost::geometry::cs::cartesian> Point; boost::geometry::model::polygon<Point> poly; boost::geometry::read_wkt("POLYGON((1074699.93 703064.65, 1074702.10 703054.62, 1074704.53 703061.40, 1074703.90 703064.58, 1074699.93 703064.65))",poly); boost::geometry::correct(poly); Point point; boost::geometry::point_on_surface(poly,point); //computed point isn't on the surface of polygon //[0] 1074839.1013086310 double //[1] 703154.77900308778 double bool res = boost::geometry::within(point,poly); // res is false }

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[property_tree] Failure with Boost 1.56
by beet 10 Oct '14

10 Oct '14

Dear all, with the release of Boost 1.56, on Ubuntu 14.04 (g++ 4.8.2, 64 bit), code like the following suddenly fails to compile: pt::xml_writer_settings<char> settings('\t', 1); pt::write_xml(someFileName, ptr_out, std::locale(), settings); "pt" is obviously an alias for boost::property_tree. The error message I'm getting is /opt/boost156/include/boost/property_tree/detail/xml_parser_writer_settings.hpp:38:35: error: 'char' is not a class, struct, or union type typedef typename Str::value_type Ch; I can see the following possibly relevant change in property_tree: In Boost 1.55, from xml_parser.hpp: ----------------------------------- template<typename Ptree> void write_xml( const std::string & , const Ptree & , const std::locale & = std::locale() , const xml_writer_settings<typename Ptree::key_type::value_type >& = xml_writer_settings<typename Ptree::key_type::value_type >() ); In Boost 1.56, same header: --------------------------- template<typename Ptree> void write_xml( const std::string & , const Ptree & , const std::locale & = std::locale() , const xml_writer_settings<typename Ptree::key_type > & = xml_writer_settings<typename Ptree::key_type >() ); So xml_writer_settings is now given a Ptree::key_type instead of a Ptree::key_type::value_type which I assume is the reason for the above error. Is there a portable way to specify the type of indention character in write_xml ? Best Regards, Beet

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[Boost.Polygon] Bug in polygon_set_data, or are my expectations wrong?
by Patrick J. LoPresti 09 Oct '14

09 Oct '14

I have just submitted a bug report: https://svn.boost.org/trac/boost/ticket/10642 ...but I am wondering if the bug is in my understanding rather than in Boost.Polygon. The test case is very simple, so I am appending it to this message. My question is, should I expect polygon_set_data<int> to scramble such a simple figure? It almost looks like some (but not all) of the coordinates are being snapped to multiples of 2. Or something. Note that doubling all of the coordinates avoids the bug. Assuming it is a bug (?) Thanks! - Pat #include <boost/polygon/polygon.hpp> #include <iostream> #include <cstdlib> namespace bp = boost::polygon; using namespace bp::operators; typedef bp::polygon_set_data<int> PolygonSet; typedef bp::polygon_data<PolygonSet::coordinate_type> Polygon; typedef bp::polygon_traits<Polygon>::point_type Point; int main(int argc, char *argv[]) { // Small figure with a little hole. Area should be 32. const Point points[] = { Point(0,0), Point(6,0), Point(6,4), Point(4,6), Point(0,6), Point(0,0), Point(4,4), Point(5,4) }; Polygon poly1(&points[0], &points[sizeof(points)/sizeof(points[0])]); PolygonSet ps1; ps1 += poly1; std::cout << "poly1 area == " << area(poly1) << "\n"; // Boost.Polygon says the area of ps1 is 30. That is because its internal // representation is wrong, as you can confirm by manually // examining the result of ps1.get() or ps1.get_trapezoids(). std::cout << "ps1 area == " << area(ps1) << "\n"; // Doubling the coordinates avoids the bug. Polygon poly2(poly1); scale_up(poly2, 2); PolygonSet ps2; ps2 += poly2; std::cout << "poly2 area == " << area(poly2) << "\n"; std::cout << "ps2 area == " << area(ps2) << "\n"; assert(area(poly2) == area(ps2)); assert(area(poly1) == area(ps1)); }

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[polygon] Incorrect output from get_trapezoids(..., HORIZONTAL)
by Patrick J. LoPresti 08 Oct '14

08 Oct '14

I apologize for sending this to the mailing list, but when I tried to file a bug report via Trac, it said "Trac thinks your submission might be Spam. To prove otherwise please provide a response to the following"... And then there was no "following". Please let me know if there is a better forum to report this sort of issue. I am using Boost 1.56. The following program uses boost::polygon to slice up a figure (with a "hole" cut out of it) into horizontal trapezoids. The output I get is: Output: polygon (4 3) (4 0) (0 0) (0 3) (4 3) ...which is clearly wrong. I am pretty sure my code is correct, because if I replace bg::HORIZONTAL with bg::VERTICAL, I get the correct output of a bunch of vertical trapezoids. For my application, I really want horizontal traps. I suppose I can just swap x and y on input and output... But this seemed worth reporting. Thanks. - Pat #include <boost/polygon/polygon.hpp> #include <iostream> namespace bp = boost::polygon; typedef bp::polygon_set_data<int> PolygonSet; typedef bp::polygon_data<PolygonSet::coordinate_type> Polygon; typedef bp::polygon_traits<Polygon>::point_type Point; std::ostream & operator<<(std::ostream &os, const Point &pt) { return os << "(" << bp::x(pt) << " " << bp::y(pt) << ")"; } std::ostream & operator<<(std::ostream &os, const Polygon &poly) { os << "polygon "; for (Polygon::iterator_type p = poly.begin() ; p != poly.end() ; ++p) os << " " << *p; return os; } std::ostream & operator<<(std::ostream &os, const PolygonSet &ps) { std::vector<Polygon> temp; ps.get(temp); os << "polygonset "; for (std::vector<Polygon>::const_iterator p = temp.begin() ; p != temp.end() ; ++p) os << " " << *p; return os; } int main(int argc, char *argv[]) { const Point points[] = { Point(2,0), Point(4,0), Point(4,3), Point(0,3), Point(0,0), Point(2,0), Point(2,1), Point(1,1), Point(1,2), Point(3,2), Point(3,1), Point(2,1) }; Polygon poly; bp::set_points(poly, &points[0], &points[sizeof(points)/sizeof(points[0])]); std::cout << "Input: " << poly << "\n"; PolygonSet ps; ps.insert(poly); std::cout << "ps = " << ps << "\n"; std::vector<Polygon> traps; // Note: bp::VERTICAL works fine bp::get_trapezoids(traps, ps, bp::HORIZONTAL); std::cout << "Output:\n"; for (std::vector<Polygon>::const_iterator p = traps.begin() ; p != traps.end() ; ++p) std::cout << *p << "\n"; }

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