November 2006 - Boost-users

[serialization] char[] and double
by Larry Smith 25 Nov '06

25 Nov '06

We have thousands of 'packed' 'C' structs (2100+) shared between C and C++ modules & apps. These structures do NOT contain any pointers, all data is contiguous so that it may be transferred directly from one machine's memory to another machine's memory without translation (32 bit Windows on Intel), e.g. #ifdef __cplusplus extern "C" { #endif typedef struct NODE_MGR { char ApplName[8]; char CompName[8]; } NODE_MGR; typedef struct ROUTE_CONTROL { UCHAR msg_type; ULONG req_num; char src_domain_id[ 15 ]; char src_machine_id[ 8 ]; char src_proc_id[ 32 ]; char dest_domain_id[ 15 ]; char dest_machine_id[ 8 ]; char dest_proc_id[ 32 ]; NODE_MGR PrimeNodeMgr; NODE_MGR BkupNodeMgr; UINT parmlen; UINT datalen; /* data[] is actually 'parmlen + datalen' bytes * in length (64K max) and contains arrays of * other struct's who's types vary based on the values * of 'msg_type' and 'req_num'. */ char data[ 1 ]; } ROUTE_CONTROL; /* hundreds of other struct defs here... */ #ifdef __cplusplus } #endif Currently, these structs are written directly from the workstation's memory to a TCP/IP socket connected to a remote server process which reads them from the socket directly into memory for immediate use by the server program (i.e. 'packed' binary structs are transfered over the net from one 32 bit Windows machine to another 32 bit Windows machine). In the near future the workstations will continue to be 32 bit Windows, but the servers may be 32 bit Linux on Intel, or 64 bit Linux on AMD, or 64 bit Linux on PowerPC, or 64 bit Solaris on Sparc. This means that we can no longer send/receive 32 bit Intel 'packed' binary structs directly from the workstation to the server. I had hoped to use Boost Archives to serialize the structs to a std::string (via std::strstream), send it across the net, then deserialize the structs at the server. However, the structs have thousands of members of the form 'char[N]' representing char arrays which are NOT nul-terminated. I can not get these struct members to serialize; I get compile errors, e.g. this fails to compile: ar & fld; // where fld is: char[200] What's the secret trick? The structs also contain many 'double' fields. If the precision is the (default?) 6 when serialized, that won't be enough. Is there a way to control the precision of doubles when they are written to a text archive? Thanks, Larry

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Re: [Boost-users] debugging templates
by Sohail Somani 25 Nov '06

25 Nov '06

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of > Maik Beckmann > Sent: Friday, November 24, 2006 10:27 AM > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] debugging templates > > Am Freitag, den 24.11.2006, 10:32 +0100 schrieb Berenguer Blasi: > > Thank you David, > > > > I think it?s a Kdbg issue (though I thought I would use gdb > behind the > > scenes)... > > > > Anybody knows something like Kgdb WITH templates? > > > > Thanks > > > > What about DDD ? > http://www.gnu.org/software/ddd/ > > I'm not an expert, but its the best(most bug free) GDB > front-end I know. cgdb is also a good one http://cgdb.sf.net

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[install] need to install 32 bit boost libraries on amd64 system
by Brian Budge 24 Nov '06

24 Nov '06

Hi all - Is it possible to build 32 bit boost libraries on amd64? When I try, I get complaints (errors) saying that pointers aren't the right size. I already have boost installed in /usr/lib64, but I need the 32 bit libs in /usr/lib32. I'm running the gentoo distribution, so a trick to build via emerge or a trick to build via tarball/configure would be great. Thanks for any help, Brian

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Wrapping variant into a smart reference
by Mathias Gaunard 24 Nov '06

24 Nov '06

I would have liked to wrap boost.variant<Base, Derived1, Derived2 .. DerivedN> into a smart reference that would act like a reference to Base. Unfortunetely, the variadic template nature makes this extremely complicated, especially since there are a lot of conversions cases to handle too (<Base, Derived1..DerivedN> should be convertible to <BaseOfBase, Base, Derived1..DerivedN>). Is there any way to code that kind of thing easily?

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Re: [Boost-users] debugging templates
by Hughes, James 24 Nov '06

24 Nov '06

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of > Berenguer Blasi > Sent: 23 November 2006 09:44 > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] debugging templates > > Hi, > > I guess the subject says it all. > > Is there a way to debug templates? with kdbg preferrably? Kgdb??? The Linux kernel debugger?? Since the kernel is all C, how can you use templates in it? Forgive me if I am missing something!! I have certainly done some debugging using _gdb_ on templated code, but it can be somewhat confusing (rather like template compile errors!), but certainly possible. James > > I've read you can with dbx but don?t know if you can with others. > > How do you do it? > > Thanks. > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users > This message (including any attachments) contains confidential and/or proprietary information intended only for the addressee. Any unauthorized disclosure, copying, distribution or reliance on the contents of this information is strictly prohibited and may constitute a violation of law. If you are not the intended recipient, please notify the sender immediately by responding to this e-mail, and delete the message from your system. If you have any questions about this e-mail please notify the sender immediately.

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boost thread exmple
by Fred J. 24 Nov '06

24 Nov '06

Hi the code below compiles and runs, but does not do what I want. how can I get the code below to print out: "I am child 1sub thread called." thanks ****************************************************************** #include <boost/thread/thread.hpp> #include <string> #include <iostream> using namespace std; class Child { string c; public: Child(string x):c(x){ } void operator()(){ cout << c << " sub thread called." << endl; } }; class Parent { string p; public: Parent(string x):p(x){} void operator()(){ cout << p << "thread called." << endl; Child c1("I am child 1"); boost::thread c1t(c1); } }; int main(){ Parent p1("I am parent 1: "); boost::thread p1t(p1); } --------------------------------- Everyone is raving about the all-new Yahoo! Mail beta.

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bind a boost::fusion::at_key
by Pierre viallet 24 Nov '06

24 Nov '06

Hi, I'm trying to bind boost::fusion::at_key, but i do not understand why the following piece of code do not compile : struct tag { class a; class b; class c; }; typedef boost::fusion::map< bf::pair<tag::a, size_t> , bf::pair<tag::b, size_t> , bf::pair<tag::c, size_t> > TMyFusionMap; TMyFusionMap aFusionMap(7,8,9); std::cout << boost::fusion::at_key<tag::b>(aFusionMap) << std::endl; //work std::cout << boost::bind(&boost::fusion::at_key<tag::b>, _1)(aFusionMap) << std::endl; //do not compile on msvc 8.0 std::cout << boost::bind<size_t &>(&boost::fusion::at_key<tag::b>, _1)(aFusionMap) << std::endl; //do not compile on msvc 8.0 any idear ? ___________________________________________________________________________ Découvrez une nouvelle façon d'obtenir des réponses à toutes vos questions ! Profitez des connaissances, des opinions et des expériences des internautes sur Yahoo! Questions/Réponses http://fr.answers.yahoo.com

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[MultiIndex] VC8: spurious compiler error
by Markus Werle 24 Nov '06

24 Nov '06

Hi! I am out of ideas here, but somebody probably fell into that trap before. Since the error message points to unrelated code, I hope to get some idea via Boost: boost_1_33_1\boost/multi_index/ordered_index.hpp(445) : error C2143: syntax error : missing ',' before '.' Since I had VC8 messing things up before I bet it is the #include order again, but I could not find the offending header yet. Markus

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Iterate over all matching items with hashed_non_unique
by Joseph Turian 24 Nov '06

24 Nov '06

I have a boost_multi_index with a hashed_non_unique key. I understand that if I do a .find() for a particular key, I can get a single entry with that key. However, I want to iterate over *ALL* the entries with this particular key, since there may be several. How do I do this? I can't figure out which is the correct end iterator. e.g. something along the following lines [haven't tried to compile] typedef FirstName string; typedef multi_index_container< Employee, indexed_by< hashed_non_unique<member<tag<FirstName>, Employee,FirstName,&Employee::first_name> > > > employee_set; typedef employee_set::index<FirstName>::type example_set_by_movie; boost::multi_index::get<FirstName>(m_employees).find("john"); -- http://www.cs.nyu.edu/~turian/

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[serialization] Difficulties with shared_ptr and export.hpp
by Deane Yang 24 Nov '06

24 Nov '06

First, I am trying to figure out how to use BOOST_CLASS_EXPORT. I am trying to do it using the following advice from the documentation: "As noted in the comments, this would work. But #include <.../export.hpp> can't be used without conflicting with other modules which use #include <.../*archive.hpp>. In this case we can move the export to an implementation file: // A.cpp #include "A.hpp" ... // export.hpp header should be last; #include <boost/serialization/export.hpp> ... BOOST_CLASS_EXPORT(A) ..." In fact, my implementation file contains *only* BOOST_CLASS_EXPORT statements. Code like this seems to compile only if I also include archive headers like: #include <boost/archive/xml_oarchive.hpp> #include <boost/archive/xml_iarchive.hpp> If these directives are omitted, then my code does not compile. Is this correct? (I didn't see anything about this in the documentation) But now if a class that is being exported contains a boost::shared_ptr<..> member (so I have to #include boost/serialization/shared_ptr.hpp), then I get the following compilation errors (in MSVC8.0express): ..\..\..\vendor\boost\boost/serialization/shared_ptr.hpp(134) : error C2039: 'reset' : is not a member of 'boost::archive::naked_xml_iarchive' ..\..\..\vendor\boost\boost/archive/xml_iarchive.hpp(91) : see declaration of 'boost::archive::naked_xml_iarchive' ..\..\..\vendor\boost\boost/serialization/split_free.hpp(58) : see reference to function template instantiation 'void boost::serialization::load<Archive,AndrewKalotayAssociates::Basic::Output::ValuationReport>(Archive &,boost::shared_ptr<T> &,const unsigned int)' being compiled Can someone tell from this what I'm doing wrong?

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