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[heap] Boost heap and default constructors for comparators
by Evan Driscoll 17 Feb '12

17 Feb '12

The Boost heap library (at least binomial and fibonacci heaps) requires a default constructor of its comparator in order to call 'pop()' on a heap. I ran into this because I was trying to use a std::binary_negate<> wrapper around another comparator: this has no default constructor. So it's pretty easy to work around; I just have to provide a custom version of binary_negate. However, is this intentional? Should it be fixed? The problem is a little strange; it only surfaces if you call the 'pop()' function of the heap. If you look at the error location, binomial_heap.hpp:831, it is // private constructor, just used in pop() explicit binomial_heap(node_list_type & child_list, size_type size): super_t(value_compare()) To wit, with 1.49 beta 1: #include <boost/heap/binomial_heap.hpp> using namespace boost::heap; struct cmp { # ifdef MAKE_DEFAULT_CONSTRUCTOR cmp() {} # endif cmp(int a) {} bool operator() (int a, int b) const { return a < b; } }; int main() { cmp c(1); binomial_heap<int, compare<cmp> > h(c); h.push(1); # ifdef CALL_POP h.pop(); # endif } Compiling with CALL_POP undefined works. Adding -DCALL_POP then causes a compiler error (the following from GCC 4.3.2, but also witnessed with MSVC10): boost_1_49_0_beta1/boost/heap/binomial_heap.hpp: ... heap.cpp:21: instantiated from here boost_1_49_0_beta1/boost/heap/binomial_heap.hpp:831: error: no matching function for call to ‘cmp::cmp()’ heap.cpp:9: note: candidates are: cmp::cmp(int) heap.cpp:5: note: cmp::cmp(const cmp&) Adding -DMAKE_DEFAULT_CONSTRUCTOR works again.

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Can boost be compiled on WinCE?
by Luke Walker 17 Feb '12

17 Feb '12

Hi,I'm required to compile existing code on WinCE that uses boost::asio, boost::thread, boost::system and boost::spirit (wide strings). I attempted this and made allot of progress but eventually ran into so many dead-ends (locale, wide strings, etc, etc) that I had to quit and make this post. My questions are: Can these 4 libraries be compiled and used on WinCE? I'm not seeking a theoretical answer but rather "Has this been accomplished?". After scouring google, etc for two days straight have not found any reference to any person that actually compiled and got boost working on WinCE. I did however find plenty of evidence that it's being "attempted". Most of the posts remain unanswered. I would appreciate some help here. Thanks and take care.

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undefined reference to '__sync_add_and_fetch_4' when cross-compiling boost::asio fors mips
by Jayne 17 Feb '12

17 Feb '12

Hello, I'm trying to build Boost 1.48.0 for use with the WebSockets++ library on a MIPS based embedded Linux board. My build machine reports itself as: Linux version 2.6.40.4-5.fc15.x86_64 (mockbuild(a)x86-10.phx2.fedoraproject.org) (gcc version 4.6.0 20110603 (Red Hat 4.6.0-10) (GCC) ) #1 SMP Tue Aug 30 14:38:32 UTC 2011 My cross-compiler version is: mipsel-linux-g++ (GCC) 4.2.0 20070124 (prerelease) - BRCM 11ts-20090508. I don't have any control over this as its provided by the chip manufacturer. I can build Boost without any reported errors and can link to and use most of the libraries without any problems. However, when WebSockets tries to link to the Boost::asio library I get link errors like this: (.gnu.linkonce.t._ZNSt5dequeIN5boost13intrusive_ptrIN11websocketpp7message4dataEEESaIS5_EE16_M_push_back_auxERKS5_+0x30): undefined reference to `__sync_add_and_fetch_4' (.gnu.linkonce.t._ZNSt5dequeIN5boost13intrusive_ptrIN11websocketpp7message4dataEEESaIS5_EE16_M_push_back_auxERKS5_+0x80): undefined reference to `__sync_add_and_fetch_4' (.gnu.linkonce.t._ZN11websocketpp9processor4hybiINS_10connectionINS_8endpointINS_4role6serverENS_6socket5plainENS_3log6loggerEEENS5_ISA_E10connectionENS7_ISA_E10connectionEEEE19prepare_close_frameEN5boost13intrusive_ptrINS_7message4dataEEENS_5close6status5valueERKSs+0xc8): more undefined references to `__sync_add_and_fetch_4' follow I've done enough research to find this has been a problem in the past with ARM chips and is to do with atomic transactions not being implemented by gcc for the target machine. I've tried the suggested fixes for ARM which were to build with either BOOST_SP_DISABLE_THREADS or BOOST_SP_USE_PTHREADS but that didn't help with my MIPS environment. Can anyone make any suggestions as to what I could try next? thanks, Jayne.

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[serialization] compile-time detection of whether serialization is implemented for a class
by Nelson, Erik - 2 17 Feb '12

17 Feb '12

I'm using the Serialization library and am trying to find a way to detect at compile-time whether or not serialization is implemented for a given type. For example, if I have #include "boost/archive/binary_oarchive.hpp" #include <strstream> struct A{}; void function() { const A a; std::strstream s; boost::archive::binary_oarchive oa(s); oa << a; } I get an error (as expected) along the lines of C:\work\boost\boost/serialization/access.hpp(118): error C2039: 'serialize' : is not a member of 'A' What I'd like is a compile-time way of detecting that 'A' is not serializable, maybe Boost Type Traits-style, something like is_serializable<A>::value or is_serializable<binary_oarchive, A>::value that can detect whether or not the object has serialization available. If it could work for testing pointer serialization as well (is_serializable<A*>::value or is_ptr_serializable<A>::value) that would be doubly super. Thanks Erik ---------------------------------------------------------------------- This message w/attachments (message) is intended solely for the use of the intended recipient(s) and may contain information that is privileged, confidential or proprietary. If you are not an intended recipient, please notify the sender, and then please delete and destroy all copies and attachments, and be advised that any review or dissemination of, or the taking of any action in reliance on, the information contained in or attached to this message is prohibited. Unless specifically indicated, this message is not an offer to sell or a solicitation of any investment products or other financial product or service, an official confirmation of any transaction, or an official statement of Sender. Subject to applicable law, Sender may intercept, monitor, review and retain e-communications (EC) traveling through its networks/systems and may produce any such EC to regulators, law enforcement, in litigation and as required by law. The laws of the country of each sender/recipient may impact the handling of EC, and EC may be archived, supervised and produced in countries other than the country in which you are located. This message cannot be guaranteed to be secure or free of errors or viruses. References to "Sender" are references to any subsidiary of Bank of America Corporation. Securities and Insurance Products: * Are Not FDIC Insured * Are Not Bank Guaranteed * May Lose Value * Are Not a Bank Deposit * Are Not a Condition to Any Banking Service or Activity * Are Not Insured by Any Federal Government Agency. Attachments that are part of this EC may have additional important disclosures and disclaimers, which you should read. This message is subject to terms available at the following link: http://www.bankofamerica.com/emaildisclaimer. By messaging with Sender you consent to the foregoing.

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Boost Python and Crypto++
by Boost Users List 16 Feb '12

16 Feb '12

Hi, I'm trying to use Crypto++ with boost::python. My code seems to build OK, but when I try to import it into Python, I receive this error: ImportError: nf_decrypt.so: undefined symbol: _ZN8CryptoPP21SimpleKeyingInterface6SetKeyEPKhmRKNS_14NameValuePairsE Here is the cpp source code file: #include <cryptopp/aes.h> #include <cryptopp/hex.h> #include <cryptopp/modes.h> std::string nf_decrypt( const std::string& estring ) { std::string hex_pk = "00000000000000000000000000000000"; std::string hex_iv = "00000000000000000000000000000000"; std::string pk; std::string iv; std::string cipher_text; std::string plain_text; CryptoPP::StringSource ( hex_pk.c_str(), true, new CryptoPP::HexDecoder( new CryptoPP::StringSink(pk) ) ); CryptoPP::StringSource ( hex_iv.c_str(), true, new CryptoPP::HexDecoder( new CryptoPP::StringSink(iv) ) ); CryptoPP::StringSource ( estring.c_str(), true, new CryptoPP::StringSink(cipher_text) ); CryptoPP::AES::Decryption aesDecryption( (byte*)pk.c_str(), CryptoPP::AES::DEFAULT_KEYLENGTH ); CryptoPP::CBC_Mode_ExternalCipher::Decryption cbcDecryption( aesDecryption, (byte*)iv.c_str() ); CryptoPP::StringSource( cipher_text, true, new CryptoPP::StreamTransformationFilter( cbcDecryption, new CryptoPP::StringSink(plain_text))); return plain_text; } // python wrapper #include <boost/python.hpp> BOOST_PYTHON_MODULE(nf_decrypt) { boost::python::def("nf_decrypt", nf_decrypt, boost::python::args("string_to_decrypt"), "nf_decrypt docstring"); } Has anyone built boost python extensions from Crypto++ code? I may try doing the same thing with Botan if Crypto++ in general is problematic. I can send my Jamroot file if that would be helpful. Thanks for any advice.

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[boost.iostreams] using zlib with wide streams
by Sean Farrow 16 Feb '12

16 Feb '12

Hi: Is is possible ot use zlib/bzip2 with wide streams. Any help appreciated. Cheers Sean.

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Re: [Boost-users] Developing a new boost archive
by Roberto Fichera 16 Feb '12

16 Feb '12

Actually I cannot really answer because I haven't had yet a deeper look at the suggest "export" method details. Neverthelss, what I need is an explicit string because certain format might require such information used to instantiate objects of the given class while deserializing in other languages (java or python for example). But also pure text formats optionally provide this information with the purpose of helping the user to understand/verify the content of the result of the serialization. My library, which is written in pure C code for compatibility reasons, does solves easily the problem by stringify the given type via pretty straight macro inside the serialization function itself. Something like opening a type, serialize all the fields and close the type. The use of the macro obviously doesn't work at all when using it under any template declaration because the preprocessor is called earlier in compilation process. I also tried the parsing of the __PRETTY__FUNCTION__ which works perfectly under template function, but this approach is even more un-portable then the demangler, so not really praticable. Sent from my ASUS Eee Pad Larry Evans <cppljevans(a)suddenlink.net> wrote: >On 02/15/12 12:38, Robert Ramey wrote: >> Roberto Fichera wrote: >>> On 02/15/2012 06:01 PM, Robert Ramey wrote: >> >>>> c) Even worse, the aproach above would make even text archives >>>> non-portable between platforms. Of course this is a non-starter. >>>> So you might want to re-think your approach above. >>> >>> I agree totally with you! Actually my constraint is to use gnu >>> toolchain, >>> MSVC and pathscale compilers and eventually LLVM, but this one is not >>> a priority at moment. But, any way still the problem of the demangling >>> portability. >>> >>> By the way, how did you solve the problem ... if you solved it, >>> indeed ;-) ? >> >> It is already solved portably via the "export" functionality. Look >> it up in the documentation. >> >> Robert Ramey >Hi Robert, > >Looking at: > > http://www.boost.org/doc/libs/1_48_0/libs/serialization/doc/serialization.h… > >and reading: > > The system "registers" each class in an archive the first time an > object of that class it is serialized and assigns a sequential > number to it. Next time an object of that class is serialized in > that same archive, this number is written in the archive. So every > class is identified uniquely within the archive. When the archive > is read back in, each new sequence number is re-associated with the > class being read. Note that this implies that "registration" has to > occur during both save and load so that the class-integer table > built on load is identical to the class-integer table built on > save. In fact, the key to whole serialization system is that things > are always saved and loaded in the same sequence. This includes > "registration". > >And paraphrasing part as: > > So every class is identified by this uniquely assigned sequential > number within the archive. > >Then I'd infer that this "uniquely assigned sequential number" play >a role similar to the role of the result of: > > abi::__cxa_demangle( typeid( T ).name(), 0, 0, NULL ); > >in Roberto's post: > > http://article.gmane.org/gmane.comp.lib.boost.user/72805 > >As you mention, Roberto's method is not portable between platforms >(where, of course, a different compiler or even different version >of the same compiler would be a different platform). > >OTOH, as you also mention in the above quote, boost serialization >requires: > > things are always saved and loaded in the same sequence. > >Roberto, would that be a problem for you? > >-regards, >Larry > > > > > >_______________________________________________ >Boost-users mailing list >Boost-users(a)lists.boost.org >http://lists.boost.org/mailman/listinfo.cgi/boost-users

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[Program_options] How to parse a command-line incrementally
by Olaf Meeuwissen 16 Feb '12

16 Feb '12

Hi all, I'm looking to implement an "incremental" command-line parser using Boost.Program_options. The parser should be incremental in the sense that parsing should stop at the first unknown option or positional argument. At this point, my program would pick the next options description and continue parsing with that. This would proceed until the command-line has been parsed completely or the program is no longer interested in the remainder. The idea is to use this for a program that interfaces to a collection of commands that each support a set of actions. The program, commands and actions all have their own list of options, so you get command-lines like so prog [prog-opts] [cmd [cmd-opts] [act [act-opts]]] Eventually, I might want to throw in positional arguments for some or each of these as well. Any suggestions on how to achieve this? My main concerns are with the way Boost.Program_options wants to parse the whole command-line (when using allow_unregistered()) every time and with how to keep track of what still needs to be processed. Thanks in advance, -- Olaf Meeuwissen, LPIC-2 FLOSS Engineer -- AVASYS CORPORATION FSF Associate Member #1962 Help support software freedom http://www.fsf.org/jf?referrer=1962

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Boost Phoenix Arguments Passing & Storage (-- Proper Type?) & Application to RValues -- Possible?
by Matt 15 Feb '12

15 Feb '12

Hi there! I've got a question (two, in fact) regarding Arguments in Boost Phoenix. Assuming using boost::phoenix::arg_names::arg1; using boost::phoenix::val; using boost::phoenix::ref; using boost::phoenix::cref; Why does this compile (and works): int x = 1; int y = 2; std::cout << (arg1 % 2 == 1)(x) << '\n'; std::cout << (arg1 % 2 == 1)(y) << '\n'; while these fail to compile (with an extremely long diagnostic involving "boost::error_cant_deduce_type"): std::cout << (arg1 % 2 == 1)(1) << '\n'; std::cout << (arg1 % 2 == 1)(2) << '\n'; std::cout << (arg1 % 2 == 1)(val(1)) << '\n'; std::cout << (arg1 % 2 == 1)(val(2)) << '\n'; std::cout << (arg1 % 2 == 1)(cref(1)) << '\n'; std::cout << (arg1 % 2 == 1)(cref(2)) << '\n'; I run into this was while attempting to store an Arg. into a variable, i.e.,: auto f = (arg1 % 2 == 1); this works: std::cout << f(x) << '\n'; std::cout << f(y) << '\n'; while this fails: std::cout << f(1) << '\n'; std::cout << f(2) << '\n'; I'm guessing this must be for the same reason the above attempts fail. Another question is, what's the "proper" type of "f" assuming non-C++11 compiler? I'd like to avoid wrappers like boost::function (assuming that's even possible). Later on, I'd like to return such an "f" from a function, hence the question (in C++11 I can get away with decltype for short and easy ones, i.e., prototypes like this "auto newActor() -> decltype((arg1 % 2 == 1))" work, but this becomes inconvenient for longer bodies). A concoction like this compiles but doesn't produce an output: auto f = (val(arg1) % 2 == 1); std::cout << f(val(0)) << '\n'; // and I'm guessing this is very wrong anyway due to unusual behavior. Best, Matt

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Developing a new boost archive
by Roberto Fichera 15 Feb '12

15 Feb '12

Hi All in the list, I'm basically new to boost so I hope to find support here to integrate my own serialization library within the boost archive logic. I would say as premise that I started to have a look in all the boost archive implementation so binary, xml and text trying to understand the logic but that increased my confusion about how to approach the solution of my problem. Confusion that is increased by the lack of my boost knowledge and it's related template programming, of course. By the way I found really instructive the simple_log_archive example that cleanly shows how to "walk" the full tree of the data representation in terms of serialization chain. Furthermore, I would say that my serialization framework does already handle all the representation formats like binary, xml, text, python and many others, so from the boost archive point of view I need just to know very few things: - how to walk the tree representing the serialization chain - how to detect that a new type is being serialized - how to get the type name as string - how to define primitive types - how to manage vectors/arrays - be sure that everything is passed as nvp About the two first, they seems related because the code below seems responsible to walk the tree and call all the serialize functions template< class Archive > struct save_only { template< class T > static void invoke( Archive & ar, const T & t ) { // make sure call is routed through the highest interface that might // be specialized by the user. boost::serialization::serialize_adl( ar, const_cast< T & >( t ), boost::serialization::version< T >::value ); } }; So I've put my two functions that are used to defines types: myserialize_beginType( myserialize &s, char *fieldName, char *type ) myserialize_endType( myserialize &s ) Such as the serialization walk chain looks like: template< class Archive > struct save_only { template< class T > static void invoke( Archive & ar, const T & t ) { // make sure call is routed through the highest interface that might // be specialized by the user. -->> myserialize_beginType( ar.serializer, ar.fieldName, ???type??? ); boost::serialization::serialize_adl( ar, const_cast< T & >( t ), boost::serialization::version< T >::value ); -->> myserialize_endType( ar.serializer ); } }; But actually I don't know how to determine the type name as string to pass to my beginType function. About the place to define primitives, I'm not really sure if it's the right place where I have to put my serialization primitives that maps all my basics types. The prototype of such overloaded function is like myserialize_serialize( "basetype" &t, char * fieldName, myserialize &s ) Actually I've defined something like: #define BOOSTSERIALIZEARCHIVE_PRIMITIVE( __T ) \ simple_log_archive & operator<<( const boost::serialization::nvp< __T > & t )\ {\ myserialize_serialize( t.value(), (char*)t.name(), this->serializer );\ return *this;\ } BOOSTSERIALIZEARCHIVE_PRIMITIVE( char ) BOOSTSERIALIZEARCHIVE_PRIMITIVE( unsigned char ) which seems to work. About managing vectors and array, actually I tried to define something like: template< class Archive > struct use_array_optimization { template < class T > static void invoke( Archive & ar, const T & t ) { myserialize_serialize( (T*)t.address(), ar.fieldName , t.count() * sizeof( T ), ar.serializer ); } }; template< class T > void save( const T &t ) { typedef BOOST_DEDUCED_TYPENAME boost::mpl::eval_if<boost::is_enum< T >, boost::mpl::identity<save_enum_type<simple_log_archive> >, // else -->> BOOST_DEDUCED_TYPENAME boost::mpl::eval_if<boost::is_array< T >, -->> boost::mpl::identity<use_array_optimization<simple_log_archive> >, //else BOOST_DEDUCED_TYPENAME boost::mpl::eval_if< // if it's primitive boost::mpl::equal_to< boost::serialization::implementation_level< T >, boost::mpl::int_<boost::serialization::primitive_type> >, boost::mpl::identity<save_primitive<simple_log_archive> >, // else boost::mpl::identity<save_only<simple_log_archive> > > > >::type typex; typex::invoke( *this, t ); } but this seems not working at all. Finally the last items, be sure that everything is passed as nvp in order to catch each given field name, I simply don't know how to do this check/constraint. Hopefully to get some support. Thanks in advance, Roberto Fichera.

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