June 2008 - Boost-users - lists.preview.boost.org

boost & c-style calback issue
by Michael Bradley Jr 04 Jun '08

04 Jun '08

Hi, i'm facing this problem may be someone on the list do have an elegant solution class A; class B; class C { int operator () (A*,B*) }; typedef int (*foobar)(A*,B*); void do_something(foobar cb); C obj; do_something(obj); *ERROR* did try boost::function<int(A*,B*)> ftor = obj; do_something(ftor); *ERROR* compiler generates in both cases the following error messages cannot convert parameter 2 from 'boost::function<Signature>' to 'int (__cdecl *)(A *,B *)' with 1> [ 1> Signature=int (A *, B *) 1> ] 1> No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called I can't make the corresponding class B member function static due to side-effects. Any clue how to get rid of this? Thanks in advance Mike

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program_options config_file questions
by Chris Ross 04 Jun '08

04 Jun '08

I'm trying to load a bunch of information out of a file, and I see that with boost::program_options 1.35.0, there's a way to pass a parameter to parse_config_file() to tell it to read in unknown "options". I am doing this, but with a config file as such: [tale] name = bob name = Jerry value = 7 I get back three options, each of which is a vector<> with only one value. Is there a way to get program_options to return tale.name as a single option with two values in the vector? I would assume so, otherwise it seems odd to have it implemented as a vector. I'm sure I must've missed something somewhere to enable that behavior, but would appreciate any pointers. Thanks. - Chris

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Convert local string to utf-8
by Li, PingShan (Kansas City) 03 Jun '08

03 Jun '08

I need to convert a big5 encoded string to utf-8 format. Is there anything in boost I can use for that? Or any suggestions? Thank you PingShan Li

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Where is Math Toolkit in the Boost Vault?
by Boris 03 Jun '08

03 Jun '08

Can anyone provide me a link to download the Math Toolkit? If I remember correctly it could be found in the Boost Vault before (but I can't find it anymore). I know that it's shipped now with Boost 1.36.0 but I can't upgrade to the latest version. Boris

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[xpressive] compilation woes with gcc 3.3.3
by Christoph Duelli 03 Jun '08

03 Jun '08

compiling #include <boost/xpressive/regex_actions.hpp> fails with gcc version 3.3.3 (SuSE Linux) (running SuSE LES9) Any chance that might be fixed? Anything I can do about it?

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[boost-users][fusion] nested map access
by Istvan Buki 03 Jun '08

03 Jun '08

Hello, I'm trying out some ideas with boost.fusion maps. Here is a small example: namespace fields { struct general { struct first_name ; struct last_name ; struct age ; } ; struct address { struct street ; struct postal_code ; struct country ; } ; } typedef fusion::map < fusion::pair< fields::general::first_name, std::string >, fusion::pair< fields::general::last_name, std::string >, fusion::pair< fields::general::age, int > > general_person ; typedef fusion::map < fusion::pair< fields::address::street, std::string >, fusion::pair< fields::address::postal_code, std::string >, fusion::pair< fields::address::country, std::string > > address_person ; typedef fusion::map < fusion::pair< fields::general, general_person >, fusion::pair< fields::address, address_person > > person ; int main() { using namespace fields ; general_person gp = fusion::make_map< general::first_name, general::last_name, general::age >( "John", "Doe", 99 ) ; address_person ap = fusion::make_map< address::street, address::postal_code, address::country >( "Foo street 1", "12345", "Barland" ) ; person a_person = fusion::make_map< general, address >( gp, ap ) ; std::cout << "Age: " << fusion::at_key< general::age >( fusion::at_key< general >( a_person ) ) << std::endl ; return 0 ; } I'm not happy with the last line that retrieve the value of a specific pair inside a nested map. I was wondering whether this could benefit from some MPL trick to make it more readable. I was thinking about something like the following: get_value< general, age >( a_person ). My questions are: 1) Is MPL the right tool to transform a call to get_value< general, age >( a_person ) into fusion::at_key< general::age >( fusion::at_key< general >( a_person ) ) 2) If it is, could someone provide me some help on how to achieve such a result? Thank you for your help

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interprocess object in memory
by Jan Suchý 03 Jun '08

03 Jun '08

Hallo boost interprocess useres, first of all, many thanks to Ion for his support: std::auto_ptr<managed_shared_memory> segment_ptr is working well and choosing keytype as interprocess::basic_string is working great too. Thank you. But now, I have stoppend when using map in shared memory in combination: typedef std::pair<MyString, XQQuery*> ValueType; where XQQuery* is pointer to object from xqilla X-Query engine: xqilla.sourceforge.net When I'am creating shared map in one process, I can see the content of the map in second process too. process one: mymap->size: 10 first: xqr_full/MW_APS_CPS_APSCreditScoringResult/REQ_BE_CPS_APSCreditScoringResult.xqr, second:0x85665a8 first: xqr_full/MW_APS_CPS_APSCreditScoringResult/RES_BE_CPS_APSCreditScoringResult.xqr, second:0x8c5ba10 first: xqr_full/MW_AccountCreate/REQ_SB_AccountCreate.xqr, second:0x80a5c08 first: xqr_full/MW_AccountCreate/RES_SB_AccountCreate.xqr, second:0x80b6000 first: xqr_full/MW_LoanCreate/REQ_SB_LoanAccountCreate.xqr, second:0x88a9c78 first: xqr_full/MW_LoanCreate/RES_SB_LoanAccountCreate.xqr, second:0x8dfe298 first: xqr_full/MW_ProductFeeGet/REQ_DON_ProductFee.xqr, second:0x8e0eb90 first: xqr_full/MW_ProductFeeGet/RES_DON_ProductFee.xqr, second:0x9620ba8 first: xqr_full/SYM_AccountGetBalance/REQ_MW_AccountBalance.xqr, second:0x97adca8 first: xqr_full/SYM_AccountGetBalance/RES_MW_AccountBalance.xqr, second:0x998ffa8 process two shows the same list.. First value is key basic_string, second is address of XQQuery object. The problem is, that the XQQuery object is ready to use only in process one, not in process two. I think, that it could be becouse of another memory adddressing between these two processes. So the second process can not see the XQQuery* objects on saved adresses. I would like to solve this problem, but I do not exactly know how to do it. I have found some hint about offse_ptr on address: http://igaztanaga.drivehq.com/interprocess/interprocess/offset_ptr.html but I do not now, if using offset_ptr will solve this problem. If yes, It will be perfect. Thank you for any information or example :-) Have a nice day, Jan Suchy

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[ptr_container] No insert(it, [key, ]value) in associative pointer container?
by Rodolfo Lima 03 Jun '08

03 Jun '08

Hi, I'd like to know why there's no method 'insert' that mimicks stl's associative container's insert method that accepts an iterator that points to where the value could be placed, and the value? Regards, rod

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boost.asio with boost.circular_buffer possible?
by james.vanns＠framestore.com 03 Jun '08

03 Jun '08

Hi, I was wondering if anyone has any experience or knows off the top of their head if it is possible (or even sensible) to use the boost.circular_buffer class as the underlying buffer for boost.asio socket reads and writes? I.e. boost::circular_buffer<char> cb (1024); bytes_transferred = sock.read (boost::asio::buffer (cb)); Similarly with write(). Regards, Jim -- James Vanns Systems Programmer Framestore CFC Ltd.

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boost serialization & C++ STL
by sam p 03 Jun '08

03 Jun '08

Is it right to use serialization library in the following environment, ********************** Main1.cpp : Compiled with Gcc stores map in /tmp/z ********************** (1) main1.cpp -------------------- #include <map> #include<string> #include <boost/archive/text_oarchive.hpp> #include <boost/serialization/map.hpp> #include <boost/serialization/string.hpp> int main() { std::ofstream f("/tmp/z"); boost::archive::text_oarchive oar(f); std::map<std::string, std::string> a; ..... //Some data added to this map oar & a; return 0; } ************************** main2.cpp : Compiled with Forte compiler (or say older version of GCC) loads map stored in /tmp/z ******************************* (2) main2.cpp ----------------------------------------------- #include <map> #include<string> #include <boost/archive/text_iarchive.hpp> #include <boost/serialization/map.hpp> int main() { std::ifstream f("/tmp/z"); boost::archive::text_iarchive iar(f); std::map<std::string, std::string> a; iar & a; return 0; } *********************************** Can such use create problems especially with STL and their vendor specific implementations? Thanks, Sameer

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