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compilation error using boost/property_tree/ptree.hpp
by Pramod Subramanyan 28 Jun '12

28 Jun '12

I am trying to use boost/property_tree/ptree.hpp in my application. All I have done so far is just add the following include statements to my program: > #include <boost/property_tree/ptree.hpp> > #include <boost/property_tree/xml_parser.hpp> After adding these lines, I compiled my modified application using g++ 4.6.3 on Ubuntu 12.04. I get the following errors: g++ -c -Wall -Werror -I../cudd-2.4.2//include/ -I /home/pramod/libraries/boost_1_50_0/ -O2 -Wno-unused-result -Wno-unused-function -c -o main.o main.cpp In file included from /home/pramod/libraries/boost_1_50_0/boost/property_tree/ptree.hpp:17:0, from main.h:10, from main.cpp:17: /home/pramod/libraries/boost_1_50_0/boost/property_tree/stream_translator.hpp: In static member function ‘static void boost::property_tree::customize_stream<Ch, Traits, bool, void>::extract(std::basic_istream<_CharT, _Traits>&, bool&)’: /home/pramod/libraries/boost_1_50_0/boost/property_tree/stream_translator.hpp:117:18: error: expected unqualified-id before ‘{’ token /home/pramod/libraries/boost_1_50_0/boost/property_tree/stream_translator.hpp:117:18: error: expected ‘)’ before ‘{’ token /home/pramod/libraries/boost_1_50_0/boost/property_tree/stream_translator.hpp: In member function ‘boost::optional<E> boost::property_tree::stream_translator<Ch, Traits, Alloc, E>::get_value(const internal_type&)’: /home/pramod/libraries/boost_1_50_0/boost/property_tree/stream_translator.hpp:191:20: error: expected unqualified-id before ‘{’ token /home/pramod/libraries/boost_1_50_0/boost/property_tree/stream_translator.hpp:191:20: error: expected ‘)’ before ‘{’ token make: *** [main.o] Error 1 When I look the lines117 and 191 in ptree.hpp, they are the following: s >> e; if(s.fail()) { // Try again in word form. and customized::extract(iss, e); if(iss.fail() || iss.bad() || iss.get() != Traits::eof()) { return boost::optional<E>(); I can't spot anything obviously wrong with either of these lines. Does anyone have any clues on what could be going wrong? Thanks! Pramod

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Anyone following boost as a git submodule?
by Chris Cleeland 28 Jun '12

28 Jun '12

Is anyone tracking boost for their project(s) as a git submodule by chance? What we've done up 'til now is import a particular boost rev directly into our repo (actually an SVN repo) but that is sub-optimal for various reasons. We're in the process of transitioning to git, so using a git submodule becomes a possibility. Wondering if anybody is doing that and, if so, if they'd be willing to discuss their experience either on list or privately. -- Chris Cleeland

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[Interprocess] Unable to Access More than 7 GB of Memory
by Hering Cheng 27 Jun '12

27 Jun '12

Hi, Using Boost.Interprocess, with either unmanaged or managed shared memory, I am unable to access beyond 7 GB of the 20 GB of memory I allocated, despite the fact that none of the Interprocess API calls returned any error or threw any exception. I run into segmentation fault when I actually try to access the portion of the memory above the (approximately) 7 GB limit. If I perform a similar test with shared memory constructed via manual calls to System V IPC, then I can access all of the 20 GB of memory without any problem. I suspect this may be due to mmap() (using by Interprocess along with POSIX shm_open() and other calls) but I have been unable to verify. Does anyone have any experience on this? The machine is running RedHat 5 with 16 GB of RAM. (Yes, when I go through the 20 GB of memory a lot of paging/swapping occurred.) From below, I do not think that the problem was due to configuration. $ uname -a Linux NJ-CEL01 2.6.18-164.11.1.el5 #1 SMP Wed Jan 6 13:26:04 EST 2010 x86_64 x86_64 x86_64 GNU/Linux $ ulimit -a core file size (blocks, -c) 2147483648 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 141312 max locked memory (kbytes, -l) 32 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 10240 cpu time (seconds, -t) unlimited max user processes (-u) 141312 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited $ grep . /proc/sys/kernel/shm* /proc/sys/kernel/shmall:4294967296 /proc/sys/kernel/shmmax:68719476736 /proc/sys/kernel/shmmni:4096 $ getconf PAGE_SIZE 4096 The following is the code for the test cases. struct entry_t { uint64_t f[10]; }; BOOST_FIXTURE_TEST_CASE(sysv_ipc, fixture) { std::cout << "System V IPC shared memory" << std::endl; const std::string shm_key = "/proc/sys/kernel/shmall"; const std::size_t shm_size = 20L * 1024L * 1024L * 1024L; const key_t ipc_key = ftok(shm_key.c_str(), 0); const int rm_rc = shmctl(ipc_key, IPC_RMID, NULL); if (rm_rc < 0) { std::cerr << "Unable to remove shared memory: " << strerror(errno) << std::endl; } const int shm_id = shmget(ipc_key, shm_size, 0644 | IPC_CREAT | IPC_EXCL); BOOST_ASSERT_MSG(shm_id >= 0, strerror(errno)); void * const shm_addr = shmat(shm_id, NULL, 0); BOOST_ASSERT_MSG(shm_addr != reinterpret_cast<void *>(-1), strerror(errno)); const std::size_t entry_count = 90L * (shm_size / sizeof(entry_t)) / 100L; entry_t * array = reinterpret_cast<entry_t *>(shm_addr); std::cout << "Initializing " << entry_count << " entries..." << std::endl; for (std::size_t i = 0; i < entry_count; ++i) { entry_t & entry = array[i]; void * addr = & entry; new (addr) entry_t(); if (i % 1000000 == 0) { std::cout << i << std::endl; } } std::cout << "Initialized all entries" << std::endl; shmctl(ipc_key, IPC_RMID, NULL); } BOOST_FIXTURE_TEST_CASE(unmanaged, fixture) { std::cout << "Unmanaged shared memory" << std::endl; const std::string shm_key = "test"; const std::size_t shm_size = 20L * 1024L * 1024L * 1024L; bipc::shared_memory_object::remove(shm_key.c_str()); bipc::shared_memory_object shm_obj(bipc::create_only, shm_key.c_str(), bipc::mode_t::read_write, bipc::permissions(0666)); shm_obj.truncate(shm_size); bipc::mapped_region region(shm_obj, bipc::read_write); const std::size_t entry_count = 90L * (shm_size / sizeof(entry_t)) / 100L; entry_t * array = reinterpret_cast<entry_t *>(region.get_address()); for (std::size_t i = 0; i < entry_count; ++i) { entry_t & entry = array[i]; void * addr = & entry; new (addr) entry_t(); if (i % 1000000 == 0) { std::cout << i << std::endl; } } bipc::shared_memory_object::remove(shm_key.c_str()); } BOOST_FIXTURE_TEST_CASE(managed, fixture) { std::cout << "Managed shared memory" << std::endl; const std::string shm_key = "test"; const std::size_t shm_size = 20L * 1024L * 1024L * 1024L; bipc::shared_memory_object::remove(shm_key.c_str()); bipc::managed_shared_memory shm(bipc::create_only, shm_key.c_str(), shm_size); typedef bipc::managed_shared_memory::allocator<entry_t>::type allocator_t; allocator_t array_alloc(shm.get_segment_manager()); const std::size_t entry_count = 90L * (shm_size / sizeof(entry_t)) / 100L; allocator_t::pointer array_ptr = array_alloc.allocate(entry_count); entry_t * array = array_ptr.get(); for (std::size_t i = 0; i < entry_count; ++i) { entry_t & entry = array[i]; void * addr = & entry; new (addr) entry_t(); if (i % 1000000 == 0) { std::cout << i << std::endl; } } bipc::shared_memory_object::remove(shm_key.c_str()); } Thanks. Hering

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Meeting C++ - Call for Papers
by Jens Weller 27 Jun '12

27 Jun '12

Dear C++/boost community! I'm proud to announce the call for papers for the Meeting C++ conference! After having talked to some people in Aspen about the plans for a C++ conference in Germany, I've decided to give it a try. Meeting C++ will take place in November in Germany, as a 2 Day C++ conference. We are looking for speakers and possible talks at our conference in fall! Possible topics could include: * (modern) C++ * C++11 * boost * C++ Frameworks like Qt, wxWidgets, Ogre, ... * other C++ related topics You'll find more information and updates at the webpage http://meetingcpp.com Tickets will be available from July at our website. regards, Jens Weller -- NEU: FreePhone 3-fach-Flat mit kostenlosem Smartphone! Jetzt informieren: http://mobile.1und1.de/?ac=OM.PW.PW003K20328T7073a

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boost asio crash
by 陈海峰 27 Jun '12

27 Jun '12

quote_server[5071] general protection rip:904f96 rsp:2aaacd41fe70 error:0 [root@linuxdev quoteserver]# addr2line -e quote_server 904f96 /usr/local/boost_1_49_0/include/boost/asio/detail/epoll_reactor.hpp:111

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boost asio crash, how to solve
by 陈海峰 27 Jun '12

27 Jun '12

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[Boost.Function] detecting ignored arguments?
by Christoph Duelli 27 Jun '12

27 Jun '12

I have a callback-interface that can optionally process a "ServerError". If the callback looks at the error, there should be no default processing of the error. I have created a class callback that accepts two kinds of Boost.Functions: one with, one without an error object. When passing a callback function that does not look at the error, the call is ambiguous: both Boost.Functions could accept it. Is there a way to work around that problem? Can callback detect what kind of function it was passed? Some code illustrating my question: #include <boost/function.hpp> class ServerError; template<typename T> struct callback { typedef boost::function<void(T)> cb_func; cb_func callback_; typedef boost::function<void(T,const ServerError&)> cb_err_func; cb_err_func callback_err_; callback(const cb_func &cb) : callback_(cb) {} callback(const cb_err_func &cb) : callback_err_(cb) {} }; static void xxx(int) {} int main (int argc, char **argv) { // does not compile: ambiguous... callback<int> cb(&xxx); // does compile: but I'd like the compiler (or my lib) to automatically pick // the right one callback<int> cb(callback<int>::cb_func(&xxx)); return 0; } In the meantime I have found a possible workaround: If I change typedef boost::function<void(T,const ServerError&)> cb_err_func; to typedef boost::function<void(const ServerError&,T)> cb_err_func; the code does compile. Best regards and thank you for looking into this Christoph

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Using boost string algorithm with BOOST_NO_STD_LOCALE
by Allan Nielsen 27 Jun '12

27 Jun '12

Hi, I'm developing for an embedded environment where we do not have a complete c++ standard library available, and one of the things missing is std::locale. But even without this feature, I would very much like to use the boost string algorithms ( split, tokenize, etc ). The only problem is that they depends on std::locale. I have been looking around in the source code, trying to see how easy it would be to add the needed ifdef's to make it work without std::locale. Most of the code looks straight forward to modify, but I'm stuck on this function: struct is_classifiedF : public predicate_facade<is_classifiedF> { // Boost.ResultOf support typedef bool result_type; // Constructor from a locale is_classifiedF(std::ctype_base::mask Type, std::locale const & Loc = std::locale()) : m_Type(Type), m_Locale(Loc) {} // Operation template<typename CharT> bool operator()( CharT Ch ) const { return std::use_facet< std::ctype<CharT> >(m_Locale).is( m_Type, Ch ); } private: std::ctype_base::mask m_Type; std::locale m_Locale; }; I know what the code does, I just do not know how it does it. This is without a doubt because I know nothing about locale, facet, etc. What I would like is another version of this struct which did not depend on std::locale, but simply assumed that the local used is "C". Something like this: struct is_classifiedF : public predicate_facade<is_classifiedF> { typedef bool result_type; is_classifiedF(std::ctype_base::mask Type) : m_Type(Type) {} template<typename CharT> bool operator()( CharT Ch ) const { // Write something here } private: std::ctype_base::mask m_Type; }; But as I do not understand the meaning/encoding of std::ctype_base::mask m_Type I found it hard to write the missing function body. So I could use some pointers/hints on how to implement this. Thanks Allan W. Nielsen

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Explicit constructing boost intrusive list
by Allan Nielsen 26 Jun '12

26 Jun '12

Hi, I would like to use a boost::intrusive::list as a static global resource, which are accessed by other global objects. To ensure that the list is initialized before it is used by "other" global objects, I have been looking in to using the "Nifty counter" method (http://en.wikibooks.org/wiki/More_C%2B%2B_Idioms/Nifty_Counter) The problem is, that the nifty counter demands that it can control construction and destruction of the object. Is there any achieve this or something similar when using intrusive::list as a global resource? Best regards Allan W. Nielsen

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[serialization] Serializing array of POD or custom type
by Kim Gadecki 26 Jun '12

26 Jun '12

Hi everyone. I'm trying to work out how you serialize arrays using the boost serializer. Here's a simplified example: struct node_link { u32 node_A; u32 node_B; }; struct Node { node_link* m_node_links_array; int m_node_links_size; }; // non-intrusive serialization template<class Archive> void serialize(Archive & ar, node_link& link, const unsigned int version) { ar & link.node_A; ar & link.node_B; } template<class Archive> void serialize(Archive & ar, Node& node_data, const unsigned int version) { ar & boost::serialization::array<node_link>(node_data.m_node_links_array, node_data.m_node_links_size); ar & node_data.m_node_links_size; } This seems to work for serializing but I get an error on de-serialization. Can anyone tell me the correct way to do this? Thanks

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