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Re: [Boost-users] Using lambda expressions in stl algorithms
by przemyslaw.sliwa＠uk.bnpparibas.com 14 Dec '10

14 Dec '10

Hello, EventTypeis a string and CurrencyEventPtr is just shared_ptr. CurrencyCouple is just a class, nothing special. typdef std::string EventType; typedef boost::shared_ptr<CurrencyEvent> CurrencyEventPtr; Thanks for help ___________________________________________________________ This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and delete this e-mail. Any unauthorised copying, disclosure or distribution of the material in this e-mail is prohibited. Please refer to http://www.bnpparibas.co.uk/en/information/legal_information.asp?Code=ECAS-… for additional disclosures.

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Using lambda expressions in stl algorithms
by przemyslaw.sliwa＠uk.bnpparibas.com 14 Dec '10

14 Dec '10

Hello, Could someone tell me why this code does not compile? Can it be modified in order to compile? struct CcyCplEventKey { CurrencyCouple CcyCpl; EventType Event; } typedef std::map<CurrencyEventKey, CurrencyEventPtr> mapType; mapType ccyOut; std::for_each(ccyOut.begin(), ccyOut.end(), (&*boost::lambda::_1)->*&CcyCplEventKey::Event); Cheers ___________________________________________________________ This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and delete this e-mail. Any unauthorised copying, disclosure or distribution of the material in this e-mail is prohibited. Please refer to http://www.bnpparibas.co.uk/en/information/legal_information.asp?Code=ECAS-… for additional disclosures.

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Variant pointer and bool
by Philipp Hamann 14 Dec '10

14 Dec '10

Hi all, I have a class, call it "Property", containing a value, which can be of many different types, like int, string, bool, but also a pointer to binary data. So I decided to use boost::variant. The problem is that when I assign a pointer to the variant, it is implicitly casted to a bool. So I do not get the pointer out of the variant again. Is boost::variant not suitable for my needs or is there a recommended workaround? I will post some code to make my problem more clear. boost::variant<void*, bool, int, std::string> value; void* p; value = p; bool b = boost::get<bool>(value); //OK void* p2 = boost::get<void*>(value); //Error Thanks for your help Philipp

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file creation/append mapping/unmapping
by Brian Budge 14 Dec '10

14 Dec '10

Hi all - I'm aware of two separate mechanisms for mapping files in boost: file_mapping combined with mapped_region from interprocess, and mapped_file from iostreams. I need to write a portable library (linux, windows, mac, 32/64 bit) which performs mappings of files. I will be creating flatfile archives consisting of many pieces of data, and this data may be operated on in a multi-threaded fashion. I was thinking of a mechanism where I'd atomically "allocate" space in a file, map that allocated region, and then memcpy the data into the region. I do not know the size of the completed file in advance. I also may be creating files > 4 GB in rare cases, and I still need this to work on 32-bit systems. I also need to be able to read (again multi-threaded) sections from one of these archives, and I need to be able to map and unmap these regions of the file. In 64-bit land, I might keep all mappings open during a process lifetime, and only close the mappings when the process shuts down, allowing the filesystem/file cache to swap out as necessary, but in 32-bit land, address space may be constrained, and I will require the map/unmap potentially many times during a process lifetime. Recommendations for which way to go on this? It seems from my little tests and reading of the existing docs that the interprocess stuff may fit the bill better than the stuff from iostreams. Also, I hope to pack my "sections" together, and not necessarily at page-aligned boundaries. I know this may incur extra state management on my part. I also found a class called managed_file_mapping. Can this help me at all? I couldn't find any example code using this class. Thanks, Brian

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Re: [Boost-users] mpi: sending/receiving different types
by Hicham Mouline 13 Dec '10

13 Dec '10

-----Original Message----- From: "Riccardo Murri" [riccardo.murri(a)gmail.com] Date: 09/12/2010 11:58 AM To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] mpi: sending/receiving different types >Hi Hicham, ><snip> >>> 3. I just thought of using boost::variant<> over all the possible types. >>> >I think this is the way to go; I'm attaching a sample program. Not >sure this is exactly what you need, but could be enough to get you >started. >Best regards, >Riccardo It's exactly what I was gonna do, thanks very much. The bit I am missing now is my question here: http://lists.boost.org/boost-users/2010/12/64797.php I don't know how to assign the most derived type to the variant at creation in the sender. In your code snippet, you explicitly construct c, then assign it to v. For me, I get given const Base& and I need to store the actual type. This seems to be what some of the boost libraries have to do themselves, but I can't remember which one exactly. I could intrusively add virtual functions to the classes but I don't want that, thanks Riccardo,

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Re: [Boost-users] mpi/serialization: broadcast function and the value argument
by Hicham Mouline 13 Dec '10

13 Dec '10

>-----Original Message----- >From: "Matthias Troyer" [troyer_at_[hidden]] >Date: 09/12/2010 02:39 PM >To: boost-users_at_[hidden] >Subject: Re: [Boost-users] mpi/serialization: broadcast function and the value argument >>On Dec 8, 2010, at 5:50 PM, Hicham Mouline wrote: >>> Following a suggestion from another thread, I have tried broadcasting in a polymorphic way. >>> >>> I have a hierarchy of polymorphic struct (they have 2 virtual functions). I was wondering if it was possible/allowed to >>> >>> root process: >>> base* b; /// b points to an actual derived struct but may also point the base struct (not abstract) >>> broadcast( ..., b, ...); >>> >>> slave processes: >>> base* b; >>> broadcast( ..., b, ...); /// broadcast constructs the appropriate struct and makes b point to where it did that >>> >>> assuming all the conditions for pointer to class conditions are satisfied for the serialization library. >>> >>If serialization works on your polymorphic class then this should work as well. >>Matthias >It appears the implementation of mpi::broadcast(), according to this post, >http://lists.boost.org/boost-users/2010/12/64802.php >and I confirm that expects an already built object to call the >(de)serialization procedure on. >Therefore, this seems a specific issue that mpi::broadcast() may want to handle differently, >could you confirm/correct? >thanks, I would very much appreciate extra opinions about this issue and the route I have taken to solve it. Let me sum up: mpi::broadcast() appears to be incapable of sending the argument "value" in a polymorphic way, ie: sender------------------- Base* base; If I call boost::mpi::broadcast(..., base, ...) receiver----------------- Base* base; boost::mpi::broadcast(..., base, ...) This does not construct the most derived type of base on the heap and make base point there, as serialization would do. I therefore used a variant made of all the classes of the hierarchy and broadcast it instead. sender------------------- variant<...> v; boost::mpi::broadcast(..., v, ...) receiver----------------- variant<...> v; boost::mpi::broadcast(..., v, ...) This works but before I replicate it in other parts of the code, I would appreciate your opinions about this solution provided by Riccardo. Regards,

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boost::filesystem without calls to Wide string versions of the win32 API
by teajay 13 Dec '10

13 Dec '10

Hello, I'm currently porting a part of code to a "smaller" version of windows which runs on a real time os. The Os provides most of the windows 32 API functions but only in the "A" variant ( using only standard characters). I got everything compiled fine up to the linker step, where the linker doesn't find the wide string versions of the API calls. Is there some way to deactivate the wide string windows API in boost::filesystem V3 ? Thanks for the help. Regards, Thomas Bernard

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boost::filesystem path problem under WINDOWS
by avanindra singh 13 Dec '10

13 Dec '10

Hi, Here is the code snippet I am using under windows in VS2008. #define BOOST_WINDOWS_PATH #define BOOST_WINDOWS_API #include "stdafx.h" #include <boost/filesystem/operations.hpp> #include <boost/filesystem/fstream.hpp> #include <iostream> #include "string" #include "conio.h" #include "vector" using namespace std; using namespace boost::filesystem; int _tmain(int argc, _TCHAR* argv[]) { string _path = "E:\\doggy"; path dir_path(_path.c_str()); vector< pair<string,bool> > _file_jpeg_pair; string full_list_path = _path+"\\" + "list.txt"; string bundle_path_str = _path+"\\" + "bundle"; path bundle_path(_path.c_str()); //creating bundle directory cout<<bundle_path<<endl; //if( !exists( bundle_path ) ) create_directory(bundle_path); cout<<"directory created "<<endl; getch(); return 0; } This code is giving run time unhandled exception, so for that matter any other call of boost filesystem. Strange thing is the Windows path E:\doggy is being printed as E:/doggy, seems like the path is getting converted to POSIX format. Can anyone please help me here?... Thanks Avanindra

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What is C++02?
by Robert Jones 13 Dec '10

13 Dec '10

Can someone confirm some terminology for me? C++98 - the current C++ standard pre tr1? C++02 - the current C++ standard post tr1? or the original target date for what has become c++0x? C++0x - the next eagerly awaited standard. Is that right? Thx - Rob.

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[math] iround / llround with rounding error
by gast128 13 Dec '10

13 Dec '10

Hello all, we want to use iround / llround without exception handling. This is possible with the 'user_error' option and override a 'user_rounding_error' function. We want to return numeric_limits<int>::max() or numeric_limits<__int64>::max() if the rounding overflows over the maximum integer domain. This is then problematic since the 'user_rounding_error' has a template argument only for its source type (e.g. float / double), but not for its target type (i.e. int / __int64). We can ofc do the check before calling iround / llround, but this check would then executed be twice for the normal non overflow case. Anyone idea?

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