September 2009 - Boost-users

Re: [Boost-users] Finding documentation for individual functions (uintmax_t)? An answer.
by s seelenluft 17 Sep '09

17 Sep '09

> in which library do I find documentation for the 'function': uintmax_t? > Since uintmax_t is such ubiquitous any search finds everything except its > actual description. Some more googling found the answer here: http://www.dinkumware.com/manuals/default.aspx Does such an equivalent, ie, a search function for functions/types only and not which does a full-text search, exist for Boost?

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Finding documentation for individual functions (uintmax_t)?
by s seelenluft 17 Sep '09

17 Sep '09

Hi, in which library do I find documentation for the 'function': uintmax_t? Since uintmax_t is such ubiquitous any search finds everything except its actual description. Thanks, Markus

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How to convert std::string into basic_string
by manish4gupta 17 Sep '09

17 Sep '09

#include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <boost/interprocess/containers/map.hpp> How to convert std::string into boost string. I am doing some benchmarking by inserting the std::string value instead of char_string(ypedef of basic_string) but i am getting error message. #include <boost/interprocess/containers/vector.hpp> #include <boost/interprocess/containers/string.hpp> #include <iostream> using namespace boost::interprocess; //Typedefs of allocators and containers typedef managed_shared_memory::segment_manager segment_manager_t; typedef allocator<void, segment_manager_t> void_allocator; typedef allocator<int, segment_manager_t> int_allocator; typedef vector<int, int_allocator> int_vector; typedef allocator<int_vector, segment_manager_t> int_vector_allocator; typedef vector<int_vector, int_vector_allocator> int_vector_vector; typedef allocator<char, segment_manager_t> char_allocator; typedef basic_string<char, std::char_traits<char>, char_allocator> char_string; class complex_data { int id_; char_string char_string_; int_vector_vector int_vector_vector_; public: //Since void_allocator is convertible to any other allocator<T>, we can simplify //the initialization taking just one allocator for all inner containers. complex_data(int id, const char *name, const void_allocator &void_alloc) : id_(id), char_string_(name, void_alloc), int_vector_vector_(void_alloc) {} //Other members... }; //Definition of the map holding a string as key and complex_data as mapped type typedef std::pair<const char_string, int> map_value_type; typedef std::pair<char_string, int> movable_to_map_value_type; typedef allocator<map_value_type, segment_manager_t> map_value_type_allocator; typedef map< char_string, int , std::less<char_string>, map_value_type_allocator> complex_map_type; int main () { //Remove shared memory on construction and destruction struct shm_remove { shm_remove() { shared_memory_object::remove("MySharedMemory"); } ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); } } remover; //Create shared memory managed_shared_memory segment(create_only,"MySharedMemory", 65536); //An allocator convertible to any allocator<T, segment_manager_t> type void_allocator alloc_inst (segment.get_segment_manager()); //Construct the shared memory map and fill it complex_map_type *mymap = segment.construct<complex_map_type> //(object name), (first ctor parameter, second ctor parameter) ("MyMap")(std::less<char_string>(), alloc_inst); string s = "hello"; char y = (char_string)s; for(int i = 0; i < 100; ++i) { char_string key_object(alloc_inst); map_value_type value(key_object, i); mymap->insert(value); } return 0; } error: no matching function for call to ‘boost::interprocess_container::basic_string<char, std::char_traits<char>, boost::interprocess::allocator<char, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void>, 0u>, boost::interprocess::iset_index> > >::basic_string(boost::interprocess_container::string&)’ /usr/include/boost/interprocess/containers/container/string.hpp:591: note: candidates are: boost::interprocess_container::basic_string<CharT, Traits, Alloc>::basic_string(typename A::size_type, CharT, const A&) [with CharT = char, Traits = std::char_traits<char>, A = boost::interprocess::allocator<char, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void>, 0u>, boost::interprocess::iset_index> >] /usr/include/boost/interprocess/containers/container/string.hpp:584: note: boost::interprocess_container::basic_string<CharT, Traits, Alloc>::basic_string(const CharT*, const A&) [with CharT = char, Traits = std::char_traits<char>, A = boost::interprocess::allocator<char, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void>, 0u>, boost::interprocess::iset_index> >] /usr/include/boost/interprocess/containers/container/string.hpp:577: note: boost::interprocess_container::basic_string<CharT, Traits, Alloc>::basic_string(const CharT*, typename A::size_type, const A&) [with CharT = char, Traits = std::char_traits<char>, A = boost::interprocess::allocator<char, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void>, 0u>, boost::interprocess::iset_index> >] /usr/include/boost/interprocess/containers/container/string.hpp:564: note: boost::interprocess_container::basic_string<CharT, Traits, Alloc>::basic_string(const boost::interprocess_container::basic_string<CharT, Traits, Alloc>&, typename A::size_type, typename A::size_type, const A&) [with CharT = char, Traits = std::char_traits<char>, A = boost::interprocess::allocator<char, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void>, 0u>, boost::interprocess::iset_index> >] /usr/include/boost/interprocess/containers/container/string.hpp:557: note: boost::interprocess_container::basic_string<CharT, Traits, Alloc>::basic_string(boost::interprocess::rv<boost::interprocess_container::basic_string<CharT, Traits, Alloc> >&) [with CharT = char, Traits = std::char_traits<char>, A = boost::interprocess::allocator<char, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void>, 0u>, boost::interprocess::iset_index> >] /usr/include/boost/interprocess/containers/container/string.hpp:548: note: boost::interprocess_container::basic_string<CharT, Traits, Alloc>::basic_string(const boost::interprocess_container::basic_string<CharT, Traits, Alloc>&) [with CharT = char, Traits = std::char_traits<char>, A = boost::interprocess::allocator<char, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void>, 0u>, boost::interprocess::iset_index> >] /usr/include/boost/interprocess/containers/container/string.hpp:539: note: boost::interprocess_container::basic_string<CharT, Traits, Alloc>::basic_string(const A&) [with CharT = char, Traits = std::char_traits<char>, A = boost::interprocess::allocator<char, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void>, 0u>, boost::interprocess::iset_index> >] /usr/include/boost/interprocess/containers/container/string.hpp:532: note: boost::interprocess_container::basic_string<CharT, Traits, Alloc>::basic_string(boost::interprocess_container::basic_string<CharT, Traits, Alloc>::reserve_t, size_t, const A&) [with CharT = char, Traits = std::char_traits<char>, A = boost::interprocess::allocator<char, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void>, 0u>, boost::interprocess::iset_index> >] Thanks in advance. -- View this message in context: http://www.nabble.com/How-to-convert-std%3A%3Astring-into-basic_string-tp25… Sent from the Boost - Users mailing list archive at Nabble.com.

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boost concept to make int template parameter available at runtime?
by Sebastian Weber 17 Sep '09

17 Sep '09

Hi! I am wondering if some boost library (like fusion) or similar may help me solve an awkward problem. In principle I have a class which has an int template parameter, for example: template <int VAL> class A { void print_val() { std::cout << "my value is " << VAL << std::endl; } }; Now I want to make the parameter VAL of class A available at runtime (of course only a limited range, but still), like this class Aruntime { void set_val(int v) { val = v; } int val; ... and again same stuff from A<val> ... }; I am sure there is an easy solution to it. One solution would be to use an object factory, I guess. There I would register for each integer the respective class A which I had to wrap into some other class in order to get rid of the template parameter and virtualize the print_val function. This may not be a boost-problem directly, but any help would be great. Thanks a lot, Sebastian

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error in getting shared vector
by manish4gupta 17 Sep '09

17 Sep '09

I am woking on IPC shared memory where i am loading one vector in memory by process1 and using the same with another program. but in process2 i am getting one error whie this code is same as given http://www.boost.org/doc/libs/1_38_0/doc/html/interprocess/quick_guide.html…. I am just doing benchmarking. May i know what is the reason behind this? Process1. #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/containers/vector.hpp> #include <boost/interprocess/allocators/allocator.hpp> int main () { using namespace boost::interprocess; try{ //Shared memory front-end that is able to construct objects //associated with a c-string. Erase previous shared memory with the name //to be used and create the memory segment at the specified address and initialize resources shared_memory_object::remove("MySharedMemory"); managed_shared_memory segment (create_only ,"MySharedMemory" //segment name ,65536); //segment size in bytes //Alias an STL compatible allocator of ints that allocates ints from the managed //shared memory segment. This allocator will allow to place containers //in managed shared memory segments typedef allocator<int, managed_shared_memory::segment_manager> ShmemAllocator; //Alias a vector that uses the previous STL-like allocator typedef vector<int, ShmemAllocator> MyVector; //Initialize shared memory STL-compatible allocator const ShmemAllocator alloc_inst (segment.get_segment_manager()); //Construct a shared memory MyVector *myvector = segment.construct<MyVector>("MyVector") //object name (alloc_inst);//first ctor parameter //Insert data in the vector for(int i = 0; i < 100; ++i){ myvector->push_back(i); } } catch(...){ shared_memory_object::remove("MySharedMemory"); throw; } shared_memory_object::remove("MySharedMemory"); return 0; } Process2 #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/containers/vector.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <algorithm> #include <iostream> int main () { using namespace boost::interprocess; try{ //A special shared memory where we can //construct objects associated with a name. //Connect to the already created shared memory segment //and initialize needed resources managed_shared_memory segment (open_only ,"MySharedMemory"); //segment name //Alias an STL compatible allocator of ints that allocates ints from the managed //shared memory segment. This allocator will allow to place containers //in managed shared memory segments typedef allocator<int, managed_shared_memory::segment_manager> ShmemAllocator; //Alias a vector that uses the previous STL-like allocator typedef vector<int, ShmemAllocator> MyVector; //Find the vector using the c-string name MyVector *myvector = segment.find<MyVector>("MyVector").first; for (MyVector::iterator it = myvector->begin(); it!=myvector->end(); it++) { std::cout << *it << "\n"; } //Use vector in reverse order std::sort(myvector->rbegin(), myvector->rend()); // . . . //When done, destroy the vector from the segment segment.destroy<MyVector>("MyVector"); } catch(...){ shared_memory_object::remove("MySharedMemory"); throw; } shared_memory_object::remove("MySharedMemory"); return 0; } Error Message: terminate called after throwing an instance of 'boost::interprocess::interprocess_exception' what(): No such file or directory Aborted -- View this message in context: http://www.nabble.com/error-in-getting-shared-vector-tp25485820p25485820.ht… Sent from the Boost - Users mailing list archive at Nabble.com.

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Concerning kolmogorov_max_flow
by townofpig Mei Ting 17 Sep '09

17 Sep '09

Hello, I am the newbie in Boost. I am actually not quite familiar with C++ but I have to employ source code for implementing kolmogorov_max_flow. When I am trying to find the input of the kolmogorov-eg.cpp, I know there is a max_flow.dat as input. However, I want to know if it is possible for me to change the input values of weight of the arcs in the graph. Where can I change it? I've spent a lot of time to find but I can't since I am really not so good at programming. Looking to forward to your replies~~ Yahoo!香港提供網上安全攻略，教你如何防範黑客! 請前往 http://hk.promo.yahoo.com/security/ 了解更多!

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How to use interprocess communication to load the data into map
by manish4gupta 17 Sep '09

17 Sep '09

Hi, I am using boost interprocess library for loading the data into map <string, string> . And reading the same map with another program.I am benchmarking the code given on the following lilnk. http://www.boost.org/doc/libs/1_38_0/doc/html/interproc/quick_guide.html#in… #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/containers/map.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <functional> #include <utility> int main () { using namespace boost::interprocess; //Shared memory front-end that is able to construct objects //associated with a c-string. Erase previous shared memory with the name //to be used and create the memory segment at the specified address and initialize resources shared_memory_object::remove("MySharedMemory"); try{ managed_shared_memory segment (create_only ,"MySharedMemory" //segment name ,65536); //segment size in bytes //Note that map<Key, MappedType>'s value_type is std::pair<const Key, MappedType>, //so the allocator must allocate that pair. typedef int KeyType; typedef float MappedType; typedef std::pair<const int, float> ValueType; //Alias an STL compatible allocator of for the map. //This allocator will allow to place containers //in managed shared memory segments typedef allocator<ValueType, managed_shared_memory::segment_manager> ShmemAllocator; //Alias a map of ints that uses the previous STL-like allocator. //Note that the third parameter argument is the ordering function //of the map, just like with std::map, used to compare the keys. typedef map<KeyType, MappedType, std::less<KeyType>, ShmemAllocator> MyMap; //Initialize the shared memory STL-compatible allocator ShmemAllocator alloc_inst (segment.get_segment_manager()); //Construct a shared memory map. //Note that the first parameter is the comparison function, //and the second one the allocator. //This the same signature as std::map's constructor taking an allocator MyMap *mymap = segment.construct<MyMap>("MyMap") //object name (std::less<int>() //first ctor parameter ,alloc_inst); //second ctor parameter //Insert data in the map for(int i = 0; i < 100; ++i){ mymap->insert(std::pair<const int, float>(i, (float)i)); } } catch(...){ shared_memory_object::remove("MySharedMemory"); throw; } shared_memory_object::remove("MySharedMemory"); return 0; } but getting the following errors. manish@user-desktop:~/Desktop$ g++ memorymap.cpp /tmp/ccmOQCB8.o: In function `boost::interprocess::shared_memory_object::priv_open_or_create(boost::interprocess::detail::create_enum_t, char const*, boost::interprocess::mode_t)': memorymap.cpp:(.text._ZN5boost12interprocess20shared_memory_object19priv_open_or_createENS0_6detail13create_enum_tEPKcNS0_6mode_tE[boost::interprocess::shared_memory_object::priv_open_or_create(boost::interprocess::detail::create_enum_t, char const*, boost::interprocess::mode_t)]+0x163): undefined reference to `shm_open' /tmp/ccmOQCB8.o: In function `boost::interprocess::detail::mutexattr_wrapper::mutexattr_wrapper(bool)': memorymap.cpp:(.text._ZN5boost12interprocess6detail17mutexattr_wrapperC1Eb[boost::interprocess::detail::mutexattr_wrapper::mutexattr_wrapper(bool)]+0x14): undefined reference to `pthread_mutexattr_init' memorymap.cpp:(.text._ZN5boost12interprocess6detail17mutexattr_wrapperC1Eb[boost::interprocess::detail::mutexattr_wrapper::mutexattr_wrapper(bool)]+0x2b): undefined reference to `pthread_mutexattr_setpshared' memorymap.cpp:(.text._ZN5boost12interprocess6detail17mutexattr_wrapperC1Eb[boost::interprocess::detail::mutexattr_wrapper::mutexattr_wrapper(bool)]+0x4d): undefined reference to `pthread_mutexattr_settype' /tmp/ccmOQCB8.o: In function `boost::interprocess::detail::mutexattr_wrapper::~mutexattr_wrapper()': memorymap.cpp:(.text._ZN5boost12interprocess6detail17mutexattr_wrapperD1Ev[boost::interprocess::detail::mutexattr_wrapper::~mutexattr_wrapper()]+0xd): undefined reference to `pthread_mutexattr_destroy' /tmp/ccmOQCB8.o: In function `boost::interprocess::shared_memory_object::remove(char const*)': memorymap.cpp:(.text._ZN5boost12interprocess20shared_memory_object6removeEPKc[boost::interprocess::shared_memory_object::remove(char const*)]+0x33): undefined reference to `shm_unlink' collect2: ld returned 1 exit stats. What is the reason for this pblm? Thanks in advance. Regards Manish -- View this message in context: http://www.nabble.com/How-to-use-interprocess-communication-to-load-the-dat… Sent from the Boost - Users mailing list archive at Nabble.com.

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boost::Interprocess sharing objects using virtual inheritance
by Martin Kaiser 16 Sep '09

16 Sep '09

hi, I am currently developing an API for PCI devices. Multiple processes should be able to use the API simultaniously, but there may be only one instance of the API and all processes have to use that same instance. So I decided to use a shared memory with a vector containing all instances of the PCI device Objects. The Problem is that my PCI Device Object uses virtual inheritance and the doc of boost::interprocess says that it isn't possible (see below). Now I am wondering if it's possible to store an offset_ptr or a kind of Ownership smart pointer in that vector pointing to my virtual inherited Device Object in a Managed Memory Segment (not memory mapped region!). Can anybode give me a hint on this? Thank in regards Martin from http://www.boost.org/doc/libs/1_39_0/doc/html/interprocess/sharedmemorybetw… : Virtuality forbidden The virtual table pointer and the virtual table are in the address space of the process that constructs the object, so if we place a class with a virtual function or virtual base class, the virtual pointer placed in shared memory will be invalid for other processes and they will crash. This problem is very difficult to solve, since each process needs a different virtual table pointer and the object that contains that pointer is shared across many processes. Even if we map the mapped region in the same address in every process, the virtual table can be in a different address in every process. To enable virtual functions for objects shared between processes, deep compiler changes are needed and virtual functions would suffer a performance hit. That's why Boost.Interprocess does not have any plan to support virtual function and virtual inheritance in mapped regions shared between processes.

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cannot pass objects of non-POD type ‘class boost::detail::shared_count’ through ‘...’; call will abort at runtime
by Dave Steffen 16 Sep '09

16 Sep '09

Hi Folks Just tried to compile my project with GCC 4.3 and Boost 1.40. (It compiles and works just fine with Boost 1.38.) As part of a home-built thread-locking shared pointer thing, we have this code: /// Constructor from pointer to complete type template<class Y> explicit shared_locking_ptr( Y * p ): px( p ), pn( p ) // Y must be complete { boost::detail::sp_enable_shared_from_this( pn, p, p ); } which now produces this result: ../util/thread/shared_locking_ptr.hpp:57:9: warning: cannot pass objects of non-POD type ‘class boost::detail::shared_count’ through ‘...’; call will abort at runtime In Boost 1.38, the relevent code in shared_ptr.hpp was this AFAICT: #ifdef _MANAGED [ ... ] #else // _MANAGED [...] inline void sp_enable_shared_from_this( shared_count const & /*pn*/, ... ) { } #endif // _MANAGED In 1.40, it's been changed to #ifdef _MANAGED [...] #else // _MANAGED inline void sp_enable_shared_from_this( ... ) { } #endif // _MANAGED Does anyone know why the change? Has anybody else seen this problem? It seems to me that GCC is correct, and that although it's an empty function so it doesn't matter anyway, the earlier version is preferable. Alternately, does anyone know of a way to silence GCC's warning? -- Dave Steffen, Ph.D - Software Engineer Numerica Corporation (www.numerica.us <http://www.numerica.us/> ) 4850 Hahns Peak Drive, Suite 200 Loveland, Colorado 80538 main (970) 461-2000 x 227 direct (970) 612-2327 fax (970) 461-2004 Email: dave.steffen(a)numerica.us

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Using rs232 libraries with Wince 5.0
by Matthew Dobrzenski 16 Sep '09

16 Sep '09

Hello, I am attempting to use the boost rs232 libraries for a wince based program I am writing. To use the serial port libraries I am including the following files: #include <boost/asio.hpp> #include <boost/asio/serial_port.hpp> Upon compilation I get the following error: fatal error C1083: Cannot open include file: 'cerrno': No such file or directory This is failing at the include of "#include <cerrno>" in the cerrno.hpp file. My compiler is visual studios 2005 (version: 8.0.50727.42), release mode, platform windows mobile 5.0 pocket pc. Thanks in advance for any help that you can offer. Matt -- Matthew J Dobrzenski Electrical Engineer/Computer Engineer

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