March 2009 - Boost - lists.preview.boost.org

[mirror] -- RFC
by Matus Chochlik 31 Mar '09

31 Mar '09

Dear Boosters, The Mirror library has been around for nearly a year. I would like to start doing the preparations for getting the library ready for a formal review and before that I would like to hear your opinions on whether this library actually belongs to Boost and any suggestions on how to improve it or what to change. For those of you who are not familiar with it, Mirror is a compile-time reflection facility with some run-time features. The sources can be downloaded from the Vault or checked out from the Sandbox (http://svn.boost.org/svn/boost/sandbox/mirror/) Since the docs (http://tinyurl.com/atba2k) do not cover everything yet, you can see the usage of several of the implemented but undocumented features in the test suite and in the examples (http://tinyurl.com/c4xygh) Some people have found the Concept browser (http://tinyurl.com/czz3t2) to be a good starting point and a useful quick reference. It, however, requires a XSLT capable web browser. It is known to work with MSIE 7+ and Firefox 3.x.y without the need to install any other software. Best regards, ________________ ::matus_chochlik

5 9

[thread] Error: cannot open file 'libboost_thread-vc90-mt-gd-1_38.lib'
by Santosh Naidu 31 Mar '09

31 Mar '09

Hi All, I am new to Boost. I am getting the following error when I try to include <boost/thread/condition_variable.hpp> Error 1 fatal error LNK1104: cannot open file 'libboost_thread-vc90-mt-gd-1_38.lib' I have followed all the steps to setup the boost library given in the startup document. Regards, Santosh

3 2

[thread] Assertion failed get_system_time_sentinel()
by Filip Klasson 31 Mar '09

31 Mar '09

Hi, I get Assertion failed timed_lock(::boost::detail::get_system_time_sentinel()), file c:\boost\thread\win32\basic_timed_mutex.hpp, line 64. Code in basic_timed_mutex.hpp: void lock() { BOOST_VERIFY(timed_lock(::boost::detail::get_system_time_sentinel())); //Line 64 } Code in thread_time.hpp: namespace boost { ... namespace detail { inline system_time get_system_time_sentinel() { return system_time(boost::posix_time::pos_infin); } ... } } I read in a previous thread that this was a known bug that is fixed in Boost 1.38 but i am using Boost 1.38. Is this another bug or is it not fixed? This only happends sometimes and it happends when i call wait on a condition variable. Here is my code, i have marked where Assertion failed happends. boost::mutex::scoped_lock lock(_mutex); while(_queue.empty()) { _condition.wait(lock); } //Assertion failed happends here. //Another thread is signaling the condition variable when an element is added to the _queue. I am happy with all sorts of helpful comments. Best regards

4 6

[iostreams] binary memory stream
by Kenny Riddile 31 Mar '09

31 Mar '09

I'm still pretty inexperienced with the iostreams library, so this may be a simple question. I'm trying to use GIL to write a PNG to a memory stream instead of a file stream. The write_view() function in the new version of GIL's io extension expects an ostream opened in binary mode as it's first parameter, such as: using namespace std; using namespace boost::gil; ofstream outputStream( "foo.png", ios::out | ios::binary ); write_view( outputStream, const_view(image), png_tag() ); I'm attempting to write to memory instead of a file, by doing this: using namespace boost::gil; using namespace boost::iostreams; typedef stream< back_insert_device< std::vector<char> > > BufferStream; std::vector<char> buffer; BufferStream bufferStream( buffer ); write_view( bufferStream, const_view(image), png_tag() ); The data that ends up in buffer is identical to the data that ends up in foo.png from the first example if I don't open outputStream in binary mode. So how can I make a binary memory stream with the iostreams library? Do I need to write my own filter?

4 6

Re: [boost] unicode tools and an unicode string type
by Graham 30 Mar '09

30 Mar '09

8. Re: [gsoc] unicode tools and an unicode string type (Mathias Gaunard) >It's really aimed at being simple and non-intrusive. Components are >fairly separate and code is thus incremental, and the unicode string >just composes the work. > >I personally believe basic_string, char_traits, and codecvt facets and >the standard locale system are not really suitable to deal with unicode, >which may have been the reason why previous proposals ended up they way >they did. >I think some people said the same in the various unicode discussions, too. >Efficient algorithms are provided by the Unicode consortium, so it's >mostly just the design or glue code that needs work. >The glue depending on what integration with other components is being >done. Here, it's mostly just range concepts. Mathias, Unfortunately the simple algorithms supplied by the Unicode consortium all end up requiring a character traits tables ! There are large tables that need to be transformed into compact sets of traits and this was done by myself and Rogier. These traits are then used to drive simple [ish] rules. So whatever you do - you need to start with the character traits tables [which are large]. Yours, Graham Barnett

1 0

Re: [boost] unicode tools and an unicode string type
by Graham 30 Mar '09

30 Mar '09

> Re: [gsoc] unicode tools and an unicode string type (Mathias Gaunard) Mathias, We are overdue a full string Unicode support library in boost. Rogier and I developed the Unicode character library that was going to underly the Unicode string libraries to provide full Unicode char, string, and iterator support [grapheme, word, paragraph iterators etc] but never had time to complete it. Any compliant Unicode text presentation system will need this and it is not possible to write a compliant Unicode text editor without it. Please have a look at the Unicode character library at: http://www.boostpro.com/vault/ Unicode_lib.zip. Good luck. Yours, Graham Barnett

1 0

[proto] transforms && rvalue refs
by troy d. straszheim 30 Mar '09

30 Mar '09

I'm playing with proto on gcc 4.3 with c++0x enabled and trying to see if I can use rvalue refs inside callable transforms, to tell what is/isn't temporary while transforming an expression. I have a different way to do this, involving embedding the 'rvalueness' of an object in its type... yuck. Hopefully something better is out there. The use case: a = exp(exp(b)); (as below), where a and b are terminals and exp is a proto lazy function. This expression should result in only one copy of b... You'd want the inner call 'exp(b)' to see that it is being passed an lvalue, copy the value to a temp, modify and return std::move(temp). The outer call to exp() should see that an rvalue has arrived and feel free to overwrite it and return it by std::move. I think. The closest I can get is below. I thought I'd ask for a sanity-check on this before go any further... I have the feeling the check will come back negative. Thanks in advance, -t #include <boost/proto/proto.hpp> #include <boost/ref.hpp> #include <cassert> namespace bp = boost::proto; // // Tag for calls to exp() in our DSEL // struct exp_tag { friend std::ostream& operator<<(std::ostream& os, exp_tag) { return os << "exp_tag"; } }; // // The terminal. Assume this thing is very heavy. Some construtors // have assert(0) in them to verify they aren't called. // // struct array_impl { std::string name; array_impl() : name("NONAME") { } array_impl(const std::string& name_) : name(name_) { std::cout << "name=" << name << "\n"; } // // constructors // array_impl(array_impl& rhs) : name(rhs.name + "_copied") { } array_impl(const array_impl& rhs) : name(rhs.name+ "_copied") { } array_impl(array_impl&& rhs) { name.swap(rhs.name); name += "_moved"; } array_impl& operator=(array_impl&& rhs) { name.swap(rhs.name); name += "_moved"; return *this; } // // not called // array_impl& operator=(array_impl& rhs) { assert(0); // just to be sure what is and isn't getting called } array_impl& operator=(const array_impl& rhs) { assert(0); // just to be sure what is and isn't getting called } array_impl& operator=(const array_impl&& rhs) { assert(0); // just to be sure what is and isn't getting called } friend std::ostream& operator<<(std::ostream& os, const array_impl&) { return os << "array_impl"; } }; // // The transform for calls to exp. You'd like to be able to see if // this is getting called with a movable object. // struct UnaryFnCall : bp::callable { typedef array_impl result_type; template <typename Tag> result_type operator()(Tag, const array_impl& t) { std::cout << "transform a const ref\n"; array_impl tmp(t); return std::move(tmp); } template <typename Tag> result_type operator()(Tag, array_impl&& t) { // this guy doesn't get called, but I'd like him to. assert(0); // if this trips, something good happened. return std::move(t); } }; struct Grammar : bp::or_<bp::when<bp::terminal<array_impl>, bp::_value>, bp::when<bp::unary_expr<exp_tag, Grammar>, UnaryFnCall(exp_tag(), Grammar(bp::_child0))> > { }; template <typename T> struct Expression; struct Domain : bp::domain<bp::pod_generator<Expression>, Grammar> { }; template <typename Expr> struct Expression { BOOST_PROTO_EXTENDS(Expr, Expression<Expr>, Domain); }; template<class T> typename bp::result_of::make_expr< exp_tag, Domain, T& >::type exp (T&& t) { return bp::make_expr<exp_tag, Domain>(boost::ref(t)); } // // Our expression type that // struct array : public Expression<bp::terminal<array_impl>::type> { typedef array_impl impl_t; impl_t& self() { return boost::proto::value(*this); } array() { assert(0); } array(const std::string& name) { self().name = name; } array(const array&) { assert(0); } array(array&&) { assert(0); } template <typename Expr> array& operator=(Expr const& expr) { bp::display_expr(expr, std::cout); BOOST_MPL_ASSERT(( bp::matches<Expr, Grammar> )); typedef typename boost::result_of<Grammar(Expr const&)>::type result_t; result_t r = Grammar()(expr); self().operator=(std::move(r)); return *this; } }; int main(int, char**) { array a("a"), b("b"); // Here, only one copy is made a = exp(b); std::cout << "a's name:" << a.self().name << "\n\n"; // Here, two copies are made a = exp(exp(exp(b))); std::cout << "a's name:" << a.self().name << "\n"; }

3 8

[gsoc] unicode tools and an unicode string type
by Mathias Gaunard 30 Mar '09

30 Mar '09

I plan to submit during the week my proposal for the Summer of Code about Unicode. I plan to provide: - iterator adaptors to iterate sequences of code units, code points and graphemes, and eventually more, from a sequence in UTF-8, UTF-16, UCS-2 or UTF-32/UCS-4. - miscellaneous utilities, such as categorization of code points - normalization functions - comparisons but not collations - substring search algorithms - and finally, an unicode string type I am well aware defining yet another new string type is quite controversial, but I believe this is quite useful. A dedicated type would be able to maintain certain invariants, such as maintaining a special normalization form. Also, I believe it can be possible to come up with a string design that allows easy integration with any other existing string type, such as the ones from the standard or Qt.

5 8

[Boost] How to generate a Bernuolli number under probablity p
by Barco You 30 Mar '09

30 Mar '09

Hi, I want to randomly generate a Bernuolli number [0, 1],with probability p ~[0 1]. How to do that with boost? Thanks! -- ------------------------------- Enjoy life! Barco You

2 1

"[gsoc] Thread scheduler support for boost"
by Indradip Ghosh 30 Mar '09

30 Mar '09

Hi Phil and Hartmut, I am following up with the earlier thread on of extending the current threadpool library present in boost. The current approach implements N:M model by internally using the pthread APIs (pthread_schedule() and its related classes). However, for high performance latency sensitive application code, we would not only like to parellize but would also like to (i) reduce load variance against the threads (ii) create asymmetric scheduling: where a set of threads are forced to run on a subset of processors (iii) prioritize the tasks amongst threads.. One that I am thinking is to create a userland scheduler through which all scheduling decisions are made. For OS specific case, the userland scheduler can be made to use features exposed by the OS such as different scheduling algos, processor affinity,... Please let me know if you think that this direction is admissible as a plausible extension for the Boost library. I am working on this and would be sending you more details on how i think on implementing this. Regards, Indradip. > Message: 4 > Date: Wed, 25 Mar 2009 07:36:12 -0500 > From: "Hartmut Kaiser" <hartmut.kaiser(a)gmail.com> > Subject: Re: [boost] "[gsoc] Thread scheduler support for boost" > To: <boost(a)lists.boost.org> > Message-ID: <49ca2540.47c1f10a.61b0.ffffdbac(a)mx.google.com> > Content-Type: text/plain; charset="us-ascii" > >> However, I thought of your suggested extension of threadpool class >> exploiting processor affinity techniques and it sounds very >> interesting as well but I guess we would run into the same portability >> issues with regard to availability of the lower level API exposing the >> hooks to be able to develop such a facility. Another issue would be to >> qualify and justify how much improvement would this type of >> parallelism enable on top of the instruction level parallelism already >> in place for all modern processors. Although, I would still like to >> find out if you have any concrete lead in mind. > > FWIW, processor affinity is supported on many operating systems, so it > shouldn't be problematic to come up with a portable implementation. > Moreover, I believe Oliver already included something like that into his > thread_pool library (see http://tinyurl.com/cqgt5u, file > boost-threadpool.v24.tar.gz). > >> I know for sure that there are those hard engineering problems in high >> performance computing domain to ensure QOS guarantees to distributed >> real-time embedded systems. They look into processor utilization >> optimizations in the face of uncertainty of computational load on the >> system. These usually require some kind of mathematical validation of >> the scheme for the system under construction. I guess that would be >> beyond the scope of the GSOC project, given the time frame. > > I'm sure that controlling processor affinity is something to consider not > only for real time applications or high end computing. With the rising > number of cores in a chip we need to be able to influence this for everyday > tasks as well. But that's only IHMO. > >> M:N type of models would also have the same portability issue as it >> requires changing kernel code as well as the userland code in thread >> library. > > You shouldn't shy away of some feature just because Boost requires portable > implementations. Most of the time this is possible to achieve, as modern > OS's have very similar functionality, just exposed using different API's. > > Regards Hartmut >

3 2

[gsoc] A graph visualization tool proposal
by naresh shenoy 29 Mar '09

29 Mar '09

Hi, I am applying for GSoC 2009. I just wanted to gauge the interest in the community for an implementation of a Graph Visualization library. This would enable the user to "see" the graphs and possibly manipulate them a la Graphviz. The proposal could be implemented using gtk+.

2 2

Re: [boost] [gsoc]built-in support for dictionary words
by raindog＠macrohmasheen.com 29 Mar '09

29 Mar '09

------Original Message------ From: Vicente Botet Sender: boost-bounces(a)lists.boost.org To: boost(a)lists.boost.org ReplyTo: boost(a)lists.boost.org Sent: Mar 28, 2009 9:39 AM Subject: Re: [boost] [gsoc]built-in support for dictionary words ----- Original Message ----- From: "Phil Endecott" <spam_from_boost_dev(a)chezphil.org> To: <boost(a)lists.boost.org> Sent: Saturday, March 28, 2009 1:30 PM Subject: Re: [boost] [gsoc]built-in support for dictionary words > > kannan venkat wrote: >> Hi ,I am a student applying for GSoC 2009. I had an idea of providing >> inbuilt support for English words found on the dictionary. > > There was a thread a few days ago about Bloom filters, did you see > that? Several people expressed an interest. I think that a Bloom > filter would work well for the problem you describe i.e. checking > password strength. Is this the sort of thing that you have in mind? > For substring searching things get more complicated e.g. suffix trees. > I guess there would be interest in that too, if it could be done in the > available time. As you know I would like to see Bloom Filters in Boost. It would be great if this support for dictionaries come with them. Vicente _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost Sent from my Verizon Wireless BlackBerry

1 0

type traites - is_virtual_base
by Robert Ramey 29 Mar '09

29 Mar '09

I've noticed that this is returning true when it should be returning false in the tests on 64 bit compilers. Is it possible that 64 bit structure alignment might be breaking the implementation? tests for SUN compilers also manifest this symptom. Maybe the has a similar cause. Robert Ramey

2 2

[gsoc] interest check for BigDecimal class
by kannan venkat 29 Mar '09

29 Mar '09

Hi, I am a student applying for GSoC 2009. I was always interested in a BigInteger class for c++ like the one provided by JAVA.i learnt that it was implemented in a previous year's GSoC. But i could not find it in the boost package i downloaded(i beg your pardon if i am wrong). Please let me know if there is scope to work on that. One more feature missing in boost is a BigDecimal class.Would it be good idea to implement the BigDecimal class with all their functionalities -overloading all arithmetic,assignement & comparison operators , functions for other basic operations. bye kannan

4 3

[gsoc]built-in support for dictionary words
by kannan venkat 29 Mar '09

29 Mar '09

Hi ,I am a student applying for GSoC 2009. I had an idea of providing inbuilt support for English words found on the dictionary. As far as i have searched i found that there isn't support for dictionary words in boost (please correct me if i am wrong & if i am trying to reinvent the wheel). In many situations i had wanted to have a list af all meaningful english words(inclusive of places & common names of people) , specially in cryptographic applications which include deciphering ciphers & other applications related to words(like finding meaningful words in a random grid of characters) . And I could not find any in-built support for this requirement.I had to write my own algorithm to work on an external list. Thus i think it might be useful. I plan to provide *support for list of all meaningful words . *efficient methods to search if a string is a valid english word. *advanced searched options for checking if a given string is a substring is of any valid english word in an efficient manner. *methods to check if any anagram of a given string is a valid english word. could you tell me if this will be a useful contribution & give suggestions if there can be any other useful feature related to this.. bye kannan

7 6

Error In undirected subgraph with no parallel edges
by Sandeep Gupta 28 Mar '09

28 Mar '09

Hi, I am using following declaration to define subgraphs over undirected graph such that parallel edges are disallowed: typedef boost::adjacency_list<vecS, setS, undirectedS, property<vertex_index_t,int>, property<edge_index_t,int> > ImplGraph_t; typedef boost::subgraph<ImplGraph_t> embeddedGraph_t; that is use setS for EdgeList instead of listS. However when I call the function local_to_global over the subgraph i end up following errors: /home/sandeep/Computing/boost_1_38_0/boost/graph/subgraph.hpp:147: error: passing ‘const std::vector<void*, std::allocator<void*> >’ as ‘this’ argument of ‘typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::reference std::vector<_Tp, _Alloc>::operator[](size_t) [with _Tp = void*, _Alloc = std::allocator<void*>]’ discards qualifiers /home/sandeep/Computing/boost_1_38_0/boost/graph/subgraph.hpp:147: error: invalid conversion from ‘void*’ to ‘unsigned int’ /home/sandeep/Computing/boost_1_38_0/boost/graph/subgraph.hpp:147: error: initializing argument 1 of ‘typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::reference std::vector<_Tp, _Alloc>::operator[](size_t) [with _Tp = void*, _Alloc = std::allocator<void*>]’ Please find the full code that creates the above scenario. Appreciate any help. -Thanks sandeep ///////////////-----------------------Undirected_Subgraph.cpp----------------------------- #include <boost/graph/subgraph.hpp> #include <boost/graph/adjacency_list.hpp> using namespace boost; typedef boost::adjacency_list<vecS, hash, undirectedS, property<vertex_index_t,int>, property<edge_index_t,int> > ImplGraph_t; typedef boost::subgraph<ImplGraph_t> embeddedGraph_t; int main() { embeddedGraph_t G; typedef graph_traits<embeddedGraph_t>::vertex_descriptor vertex_t; vertex_t v; embeddedGraph_t& G1 = G.create_subgraph(); G.local_to_global(v); return 0; }

1 0

[filesystem] detecting hidden files?
by Kenny Riddile 28 Mar '09

28 Mar '09

Does the filesystem library allow you detect whether a path refers to a hidden file or not?

1 0

Re: [boost] [gsoc]built-in support for dictionary words
by kannan venkat 28 Mar '09

28 Mar '09

i got a lot of valuable comments & suggestions . Thanks a lot!! yes bloom filters is the best option for checking if the word is present & for substrings suffix trees should do the trick as Phil Endecott suggested. Inbuilt SpellCheck was a great idea which has practical necessity.I shall try to implement if it can be done within the given period. I shall soon post another idea i had been workin on.

1 0

Can a Boost library use a component like GMP and mfpr that have a LGPL license ?
by Paul A. Bristow 28 Mar '09

28 Mar '09

I am raising this issue for discussion because it seems to me that it is important to resolve this issue before development of the GTL library by Lucanus Simonson and others. I suspect this is not the only time this will crop up, especially with the two very well developed and refined 'big' multiprecision number libraries, GMP (http://gmplib.org) and mfpr (www.mfpr.org) Boost lacks any equivalent libraries (apart from some un reviewed, but probably functional, big integer offerings). GMP and mfpr have already been used within John Maddock's Boost.Math library, but only to calculate extremely accurate reference values, so *users* do not have to use GMP and mfpr. Fernando Cacciola wrote "While in the case of GTL, it is technically up to the user to pick up "their own" multiprecision number types, they actually can't do that without an external non-boost library since such number types do not exists in the SCL." I agree that it would be unfortunate to re-invent the wheel to produce our own (probably inferior) version of these components. So what do we do? Might we enter into discussion with GMP and mfpr developers to get explicit permission to package their library within Boost? IANAL but I feel this issue should be resolved and a decision recorded. Paul --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow(a)hetp.u-net.com

15 25

[Review Request] Msm
by Christophe Henry 27 Mar '09

27 Mar '09

Hi, Msm v1.20 has now been stable for some time and managed to survive a fair number of tests, so I would like to request a formal review. The review-ready version can be found: - in the Vault: http://www.boostpro.com/vault/index.php?direction=0&order=&directory=Msm& - or better (in case of bugfixes), in the sandbox: https://svn.boost.org/svn/boost/sandbox/msm/ . You will find there the Review version under /tags/version-1.20, the most current version at the same level under /boost (or /libs for the doc). Thanks, Christophe

2 1

[Boost.Config] Using <cstddef> instead of <utility> for std lib detection
by David Deakins 27 Mar '09

27 Mar '09

I am in the process of migrating our VeecoFTC regression tests from VC8 and STLport 5.1 to VC9 and STLport 5.2. While working on this, I have experimented with turning on STLport's _STLP_USE_BOOST_SUPPORT macro. When this macro is defined, STLport will pull in the Boost.TypeTraits header files instead of its own type traits implementations. It also suppliments a few of the standard headers (memory and functional) with Boost-based TR1 functionality much like Boost.TR1 does. However, similar to some of what Boost.TR1 had to deal with, some caution is required to avoid circular dependencies in the headers. One area where this tends to come up is in detecting the standard library in use in Boost.Config. Currently config/select_stdlib_config.hpp and config/stdlib/stlport.hpp include <utility> to determine what std library is provided. However, <utility> can tend to pull in some code that wants type traits and thus may circularly pull in Boost. One convenient way to resolve this would be to use the much simpler <cstddef> header instead of <utlity> to determine the std lib. Is this a reasonable change to make or is there something special about using <utility> in the select_stdlib_config code? -Dave

1 0

[gsoc] Status
by troy d. straszheim 27 Mar '09

27 Mar '09

We have 9 proposals. Four of these are for the devector idea: students who have filed these overlapping proposals are encouraged to take the initiative, come up with some ideas and discuss them on the list. We have enough mentors, but it isn't clear that each proposal will match up well with an individual mentor. More mentors welcome to apply. Currently we have no way to make the current set of proposals visible to the general community. I've filed a bug with google and have reason to hope this will get resolved soon. Until then only accepted mentors can see the full list. :/ Students who are working on a proposal who haven't submitted it yet are encouraged to get a draft together, put it up on a webpage or wiki someplace, solicit comments, and refine. This can only help your chances. -t

2 2

[Boost][Random] Question on random_test.cpp
by n1driver＠charter.net 27 Mar '09

27 Mar '09

The following is an excerpt from the random_test.cpp file (part of the instantiate_urng function): urng2 = urng; { // narrow stream first std::ostringstream file; file << urng; // move forward urng(); // restore old state std::istringstream input(file.str()); input >> urng; // std::cout << file.str() << std::endl; #if !defined(BOOST_MSVC) || BOOST_MSVC > 1300 // MSVC brokenness // advance some more so that state is exercised for(int i = 0; i < 10000; ++i) { urng(); urng2(); } BOOST_CHECK(urng == urng2); #endif // BOOST_MSVC } My concern is that when a random number generator with an underlying double type (like fibonacci607) is stored to the stream and then pulled back out, then precision may be lost, and the underlying data is not guaranteed to be the same. If a double is written out to a stream in decimal form and then read back in the value may be changed. Am I missing some sort of language guarantee that this is supposed to work? I've tried this on AIX and the test failed at this point for fibonacci607 because some (but not all) of the underlying doubles had changed after the object was stored and retrieved. Thanks!

2 1

[gsoc][graph] Hierarchical graph layout algorithms.
by Daniel Arbelo 27 Mar '09

27 Mar '09

Hello, I'm a student interested in adding hierarchical layout algorithms as mentioned in https://svn.boost.org/trac/boost/wiki/soc2009#Hierarchicalgraphlayoutalgori… . Is there someone available I could discuss the details for it? Are there any prospective mentors for this proposal? I'm mostly looking to discuss a proper scope for this and what Boost needs or expects from a proposal in this area. Daniel Arbelo Arrocha

1 0

boost::interprocess -- How do I construct a anonymous object ?
by Oncaphillis 27 Mar '09

27 Mar '09

Hi, I'm using boost::interprocess (1.37) and would like to construct a couple of anonymous objects. The idea is to construct a named object via Object *o segment.find_or_construct<Object>("theObject")(); and let this one dynamically construct a couple of other objects to which it holds offset_ptrs. On destruction one could simply use segment.destroy_ptr<Object2>( myOffset.get() ); to get rid of these objects. This works fine with objects I constructed with segment.construct<Object2>("GAGA NAME")(); but the reference by name seems to be unnecessary. The doc tells something about constructing and creating of anonymous objects but so far I only find allocators or copy constructors for anonymous objects. Thanks you .... O.

2 1