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

BGL: return all available paths between two vertices
by Ioannis Nousias 01 Feb '08

01 Feb '08

Hello everyone. This is a Boost Graph library question. Is there an algorithm in the library that can return all available paths between two vertices? If not, which algorithm from the library is best to use as a bases, to define a custom visitor for it? (assuming that is the preferred approach) regards, Ioannis

4 5

How to expose self defined type in boost.python
by Huang You Gong 01 Feb '08

01 Feb '08

Hi, I try to use boost.python to invoke C++ library in Python, so I need to expose types and classes. Here is the c++ head file: *typedef int XTYPE;* *class XCLASS* *{* *public:* * XTYPE getvalue( void ){ return XTYPE( 3 ); }* *};* So I write exposing code in BOOST_PYTHON_MODULE like this: *BOOST_PYTHON_MODULE( x )* *{* * class_< XCLASS >( "XCLASS" )* * .def( "getvalue", &XCLASS::getvalue, return_value_policy< copy_non_const_reference >() )* * ;* *}* but there is compiling error as using of undefined type. what shall I do to make the type XTYPE known by boost.python? Thanks in advance! -- Huang You Gong

2 2

boost python: linking with pythonxx_d.lib
by Christian Hoffmann 01 Feb '08

01 Feb '08

Hi, I tried to compile boost python so that it links against the debug version. I therefore run bjam toolset=msvc-9.0 threading=multi python-debugging=on link=shared variant=debug libs\python\build Running it with -n shows, that it sets -DBOOST_DEBUG_PYTHON, but it still links with python25.lib. It only picks "right" python25_d.lib, if I add something to my user-config.jam, like the following: using python : 2.5 : C:\\src\\Python-2.5\\PCBuild\\python ; using python : 2.5 : C:\\src\\Python-2.5\\PCBuild\\python_d : # includes : # libs : <python-debugging>on ; What is the difference between the two methods (as a bjam argument and in the user-config.jam), and is there a way to combine both on the command line? Thanks and regards, Chris

2 1

Relationship of Lambda and Phoenix
by Scott Meyers 01 Feb '08

01 Feb '08

At BoostCon 2007, I was told that the functionality of Boost.Lambda was essentially present via Phoenix in Boost.Spirit. From what I can tell, both Lambda and Spirit/Phoenix will be present in 1.35, leading me to wonder what advice to give people who are interested in experimenting with the use of lambda functions in Boost. Are people to be encouraged to use Phoenix over Lambda, or are there features in Lambda that Phoenix doesn't have? I'll be giving an overview of some Boost libraries at the Software Development conference in March, and I'll be showing some examples of Lambda. If I should be telling people to use Phoenix for future work, I'd like to know that. Thanks, Scott

2 2

Compilation error for Boost.Function 1.34.x fix with TR1 headers.
by Robert Fairlie-Cuninghame 31 Jan '08

31 Jan '08

Hi all, I recently applied the Boost.Function critical bug fix (Dec 17) to my boost 1.34.1 library and I came up against a compilation error. However, I found that if I removed the boost/tr1/tr1 include path when building then the fixed library would compile correctly. Has anyone got the fix to work with the TR1 include paths? I haven't see any other reports of problems with it. I'm using gcc 3.3.5. The first compile error is a suspicious BOOST_FUNCTION_NUM_ARGS redefinition by the TR1 headers. The compile output was as follows: C++ build/CommandLineOptions.o In file included from release/boost-1_34_1/boost/preprocessor/iteration/detail/iter/forward1.hpp:47, from release/boost-1_34_1/boost/function.hpp:62, from release/boost-1_34_1/boost/tr1/functional.hpp:99, from release/boost-1_34_1/boost/tr1/tr1/functional:27, from release/boost-1_34_1/boost/function/function_base.hpp:18, from release/boost-1_34_1/boost/function/detail/prologue.hpp:16, from release/boost-1_34_1/boost/function/function_template.hpp:12, from release/boost-1_34_1/boost/function/detail/maybe_include.hpp:18, from release/boost-1_34_1/boost/function/function1.hpp:11, from release/boost-1_34_1/boost/program_options/value_semantic.hpp:13, from release/boost-1_34_1/boost/program_options/options_description.hpp:13, from release/boost-1_34_1/boost/program_options.hpp:13, from src/CommandLineOptions.cpp:26: release/boost-1_34_1/boost/function/detail/function_iterate.hpp:13:1: "BOOST_FUNCTION_NUM_ARGS" redefined ******** note first error here ******* In file included from release/boost-1_34_1/boost/program_options/value_semantic.hpp:13, from release/boost-1_34_1/boost/program_options/options_description.hpp:13, from release/boost-1_34_1/boost/program_options.hpp:13, from src/CommandLineOptions.cpp:26: release/boost-1_34_1/boost/function/function1.hpp:10:1: this is the location of the previous definition In file included from release/boost-1_34_1/boost/function/detail/maybe_include.hpp:13, from release/boost-1_34_1/boost/function/detail/function_iterate.hpp:14, from release/boost-1_34_1/boost/preprocessor/iteration/detail/iter/forward1.hpp:47, from release/boost-1_34_1/boost/function.hpp:62, from release/boost-1_34_1/boost/tr1/functional.hpp:99, from release/boost-1_34_1/boost/tr1/tr1/functional:27, from release/boost-1_34_1/boost/function/function_base.hpp:18, from release/boost-1_34_1/boost/function/detail/prologue.hpp:16, from release/boost-1_34_1/boost/function/function_template.hpp:12, from release/boost-1_34_1/boost/function/detail/maybe_include.hpp:18, from release/boost-1_34_1/boost/function/function1.hpp:11, from release/boost-1_34_1/boost/program_options/value_semantic.hpp:13, from release/boost-1_34_1/boost/program_options/options_description.hpp:13, from release/boost-1_34_1/boost/program_options.hpp:13, from src/lCommandLineOptions.cpp:26: release/boost-1_34_1/boost/function/function_template.hpp:98: error: variable declaration is not allowed here release/boost-1_34_1/boost/function/function_template.hpp:98: error: syntax error before `{' token .... and then a bunch more errors before it gives up. If anyone else has got this scenario to work then I'll know it must be something screwy in our setup. Cheers, Robert.

2 2

releasing code under the BSL
by Manfred Doudar 31 Jan '08

31 Jan '08

Hello all, Hoping some one might offer some guidance... (somewhat off-topic, appologies). I've developed a generic DAG library in-house and seeking to place it under the BSL, and would even go as far as a Boost review if people here want such a thing (that's the intention after all). Now, I have obtained authorization from my organization's management and their legal representatives for the software release (yippee!). However, an email trail of approvals, while legal tells me is satisfactory, I would much rather a written approval on company a letter-head. IP Counsel of the organization I work for just said I ought to draft the letter myself and just have the Lab Director sign it (, consistent with the approval already granted .. ie. "Ok to release the work under the BSL"). My question is, what exactly ought to be the wording of such a letter? All help appreciated, and again apologies if it is too far removed from Boost.users NG business. If I ought to take this question elsewhere, please do let me know. Cheers, -- Manfred Doudar - Principal Research Engineer (Software) National ICT Australia - Canberra Research Lab | www.nicta.com.au Research School of Information Sciences and Engineering (RSISE) The Australian National University - Canberra, ACT 0200 AUSTRALIA

2 1

[boost any] casting problems (BUG?)
by Ovanes Markarian 31 Jan '08

31 Jan '08

Hello *, I would like to ask the developers of boost::any if the ctor template in boost::any template<typename ValueType> any(const ValueType & value) : content(new holder<ValueType>(value)) { } is intentionally not marked as explicit. Today using boost::any_cast and with a std::map (mapping of some id to boost::any) iterator I was wondering why I got an exception when I found a correct any instance. My code looked like: map_type::const_iterator iter = map.find(Key); if(map.end()!=iter) return boost::any_cast<SomeResultType const&>(*iter); Unforturenately, I forgot that map iterator references a pair<KeyType, ValueType>. This cast caused the compiler to implicitly create a new const any type containing the dereferenced pair and throw an exception that my expected result type was wrong. I don't know which design rationale was intended when this ctor was not marked as explicit or if it is a bug. With Kind Regards, Ovanes BTW, I use boost 1.34.1 and vc 7.1.

2 1

Re: [Boost-users] Boost Thread: condition.wait()
by Kesseli Pascal 31 Jan '08

31 Jan '08

Hey Ya Thanks for the quick reply. Well, it would be more complicated in the way that the only condition that would keep in the loop would be the number of threads already arrived on this condition (numberOfThreadsReady). As soon as all threads have arrived, this number is set back to zero, which would keep the threads waiting if they re-checked this condition. But I found out that Boost supports a much more suitable solution for this problem, namely the barrier class. And, concerning the use of a barrier, I trust I am not mistaken that there is no loop needed when calling barrier.wait(), or is there :) ? If so, that would call my complete understanding of the barrier mechanism into question :) . Thanks again & greeetz Pascal "Vladimir Prus" <ghost(a)cs.msu.su> schrieb im Newsbeitrag news:<fnp5p1$cce$1(a)ger.gmane.org>... > Kesseli Pascal wrote: > > > Hi everyone > > > > Recently I was trying to synchronize one of my functions using the > > following code: > > > > // write own data to shared vector... > > // ... > > if (++numberOfReadyThreads < numberOfInvolvedThreads) { > > allChargingDataReady.wait(lock); > > return; > > } > > numberOfReadyThreads = 0; // Only the last thread enters this section. > > // write data to file... > > allChargingDataReady.singal_all(); > > > > The idea is that all threads submit their data using this function and > > then wait before reading in the next set of data until all threads have > > submitted their data. The last thread to submit his data is the one who > > has to write the collected data to a file. > > > > Using this structure, I find it very simple to realize this behavior. > > However, I know from programming with Java that the VM there sometimes > > awakens one's threads without any reason, which means that I would have to > > realize my condition like this instead: > > > > > > // ... > > while(numberOfReadyThreads < numberOfInvolvedThreads) { > > allChargingDataReady.wait(lock); > > } > > // ... > > > > Implementing the same behavior using this snippet is much more complicated > > though and I would rather avoid it if possible. > > Why is it more complicated? > > > And that leads us right > > away to my question: > > > > Is the while()-workaround using Boost & C++ needed as well as in Java? Or > > can I use the much simpler if()-version? > > As docs say, you need to test your condition in a loop in Boost.Threads. > This is not a particular property of Java or Boost.Threads -- that's how > POSIX threads work. (Windows don't have native condition, and I have much > clue how conditions are simulated on windows and whether window Event thing > has similar behaviour). > > - Volodya No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.16/1251 - Release Date: 30.01.2008 09:29

3 2

Flyweight
by Martin Fisher 31 Jan '08

31 Jan '08

My test program was as follows: [Code] // fly.cpp : main project file. #include "stdafx.h" #include <string> #include <iostream> #include <vector> #include <fstream> #include <iterator> #include <algorithm> #include <boost/progress.hpp> #include <boost/flyweight.hpp> using namespace std; vector<boost::flyweight<string> > vec; //vector<string> vec; struct Insert { void operator()(string s) { vec.push_back(boost::flyweight<string>(s)); //vec.push_back(s); } }; void Test() { fstream f("d:\\bible12.txt", ios_base::in); // A large text file! { boost::progress_timer t; for_each(istream_iterator<string>(f), istream_iterator<string>(), Insert()); } } int main(int argc, char* argv[]) { Test(); cout << vec.size() << endl; getchar(); copy(vec.begin(), vec.begin() + 200, ostream_iterator<string, char>(cout, " ")); getchar(); return 0; } [/Code] Using the boost_1_35_0 svn library download and Visual C++ 2008 Express edition. Originally compiled as a CLR program. Recompiling using native Win32 still gives a crash during program termination - in atomic_count_win32.hpp in operator-- (BOOST_INTERLOCKED_DECREMENT) Unhandled exception at 0x010752b9 in fly2.exe: 0xC0000005: Access violation writing location 0x00779040. There is still the anomaly of release version being slower than debug. Compiled as release - the exception occurs in xmemory in _Destroy_range. I'll experiment using set_factory in Borland - although I have largely abandoned it's use, just can't compile enough of Boost to be useful now... Martin

3 4

[boost-users] [general question].
by chun ping wang 31 Jan '08

31 Jan '08

Hey guys does anyone know any good template engine for c++. I mean not like c++ template programming but web template engine that are easy to use, works on multiple platform, etc... Example Smarty <http://www.smarty.net/> for php. Velocity <http://velocity.apache.org/> for java. Cheetah <http://www.cheetahtemplate.org/> for python. Is their an ongoing project for boost to do this? Thanks, Chun Ping Wang.

3 3

BGL - changing internal values of a graph
by Renato Golin 31 Jan '08

31 Jan '08

Hi, I'm trying to write a simple graph: // Link and Edge types struct Link { std::string name; }; struct Edge { long count; }; // directed graph typedef boost::adjacency_list < boost::vecS, boost::vecS, boost::directedS, Link, Edge > graph_t; // Vertex and Edge descriptors typedef boost::graph_traits < graph_t >::vertex_descriptor link_d; typedef boost::graph_traits < graph_t >::edge_descriptor edge_d; // Map with all vertexes and links (deduplicate) typedef std::map < std::string, link_d > link_map_t; And my method to add a vertex (which is working well) is: link_d Chain::addVertex (string& name) { link_map_t::iterator pos; link_d descriptor; Link link; bool inserted; // Insert into map boost::tie(pos, inserted) = links.insert(make_pair(name, link_d())); // Insert into graph (or get descriptor) if (inserted) { link.name = name; descriptor = add_vertex(link, graph); pos->second = descriptor; cerr << "Added new vertex: " << graph[descriptor].name << endl; } else { descriptor = pos->second; cerr << "Reused old vertex: " << graph[descriptor].name << endl; } return descriptor; } And my method to connect the edges (which is not working) is: void Chain::addConnection (string subject, string object) { link_d sub, obj; edge_d pred; Edge e; bool inserted, found; // Add vertices sub = addVertex(subject); obj = addVertex(object); // Connect through predicate and increment counter boost::tie(pred, found) = edge (sub, obj, graph); if (found) { e = graph[pred]; cerr << "Old, pred: " << pred << " count: " << e.count << endl; e.count++; } else { e.count = 1; } boost::tie(pred, inserted) = add_edge(sub, obj, e, graph); e = graph[pred]; // Print to see if it was correct cerr << "New, pred: " << pred << " count: " << e.count << "\n" << endl; } By reading a text line "ABABAB." and taking letter by letter and inserting into sub and obj (A,B), (B,A) ... I have the following output: line [ABABAB.] Added new vertex: first Added new vertex: A New, pred: (0,1) count: 1 Reused old vertex: A Added new vertex: B New, pred: (1,2) count: 1 Reused old vertex: B Reused old vertex: A New, pred: (2,1) count: 1 Reused old vertex: A Reused old vertex: B Old, pred: (1,2) count: 1 New, pred: (1,2) count: 2 Reused old vertex: B Reused old vertex: A Old, pred: (2,1) count: 1 New, pred: (2,1) count: 2 Reused old vertex: A Reused old vertex: B Old, pred: (1,2) count: 1 New, pred: (1,2) count: 2 Reused old vertex: B Added new vertex: . New, pred: (2,3) count: 1 Reused old vertex: . Added new vertex: last New, pred: (3,4) count: 1 The creation and reuse of vertices is working pretty well as you can see but the edge, even when reused doesn't have its value updated on a second time. It may be a very stupid problem (not even in BGL) but can you help me find out what's going on? Basically, the following part works while inside the function: if (found) { e = graph[pred]; cerr << "Old, pred: " << pred << " count: " << e.count << endl; e.count++; } I'm getting it again from the graph in order to assure it changed: boost::tie(pred, inserted) = add_edge(sub, obj, e, graph); e = graph[pred]; And even when using a new variable: boost::tie(pred, inserted) = add_edge(sub, obj, e, graph); Edge f; f = graph[pred]; My cerr still produces the correct value. But when I get it a few iterations later the value is 1 again. What's going on? Or better, how to change the value of the structure inside the graph? thanks, --renato

2 2

Re: [Boost-users] [boost] [review] Fast track review of Boost.Utility/Singleton - rejected for now
by John Torjo 31 Jan '08

31 Jan '08

Hi Tobias, > >> I would like to see this into Boost, so I hope Tobias will update the >> library, given all this feedback, and I would suggest another review in >> 2-3 months. I'd like to be the review manager then as well, if Tobias >> will still want me. >> > > I've no objections to the review manager part but I'm afraid that I'll > have to put this one on hold, as I don't have enough time nor energy for > a redesign in the immediate future. Right now, I can't promise anything, > so I'm fine with "just reject" for now :-). > > > Ok. Please let me know when you're ready to revive it. Best, John > Regards, > Tobias > > _______________________________________________ > Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost > > -- http://John.Torjo.com -- C++ expert ... call me only if you want things done right

2 1

[flyweight] Review
by Neil Hunt 30 Jan '08

30 Jan '08

* What is your evaluation of the design? I like ability for the drop in replacement of const T (with assignability). It makes it easy to test whether it makes a big difference in run time scenarios, before committing to its use. I liked the policy based interface. * What is your evaluation of the implementation? I had a small hunt around the code and liked the modularity of it. A friend of mine railed against the default use of a static factory. He would prefer, by default, to control the lifetime of the factory, but that would make it harder for "drop in" usage, and there is the flexibility of overriding the holder class. * What is your evaluation of the documentation? I didn't read it all closely, but I certainly understood what the library was for and how to use it after viewing the docs. Of course, real world mileage will vary, but some performance indicators or at least discussion of the tradeoff of extra hashing vs reduced dynamic allocations would be useful, as well as any other performance impacts (how big should the data set be before using it, what percentage of unique values makes it worthwhile). * What is your evaluation of the potential usefulness of the library? Useful to have available. Unless there is a no brainer scenario, it seems that real world testing on live data will be needed to evaluate it's value in any given scenario? * Did you try to use the library? With what compiler? Did you have any problems? I didn't try the library, since I am not using 1.35. But I am keen to use it when 1.35 is released. * How much effort did you put into your evaluation? A moderate investigation. * Are you knowledgeable about the problem domain? No experience making an implementation, but knowledgable about the problem. * Do you think the library should be accepted as a Boost library? Yes Neil Hunt

2 1

[boost::any] any chance that someone will take a look at my previous post?
by Ovanes Markarian 30 Jan '08

30 Jan '08

Hi! I posted this post http://lists.boost.org/boost-users/2008/01/33607.php 2 days ago. Can someone of the developers give a statement on this issue? Many thanks, Ovanes

1 0

Flyweight
by Martin Fisher 30 Jan '08

30 Jan '08

/* boost::flyweights::flyweight<string>::initializer init; vector<boost::flyweights::flyweight<string> > vec; */ Thanks Joaqu?n. That fixes all. I'd noticed a bit in the doc about initialisation - just my attempt to write a minimal test case got the better of me. Release is still slower than debug under MS - 60 cf 56s with my computer cranked up to full tilt.. Put that down to some dubious MS code generation. For comparison the example program took 927s for hashed factory when compiled as debug and 1365s when compiled as release (ok I didn't repeat the tests!) I'll have to get a smaller test file :-) Best wishes Martin

2 1

[multi-index] No constructor that takes allocator only
by Michael Fawcett 30 Jan '08

30 Jan '08

Joaquín, thanks so much for a wonderful library. I was wondering why there is no constructor that simply takes an allocator. This would make multi_index behave more like STD Library containers, which would aid me in allowing flexible storage options for generic algorithms. Is there a technical hurdle that makes this difficult to do? You currently provide: explicit multi_index_container( const ctor_args_list& args_list=ctor_args_list(), const allocator_type& al=allocator_type()); template<typename InputIterator> multi_index_container( InputIterator first,InputIterator last, const ctor_args_list& args_list=ctor_args_list(), const allocator_type& al=allocator_type()); Is it possible to also provide: explicit multi_index_container( const allocator_type& al=allocator_type()); ? Thanks again! --Michael Fawcett

4 5

Boost Format: format strings and character types
by Daniel James 30 Jan '08

30 Jan '08

The documentation states that the same format string used with printf and boost::format should result in the same output in "almost all cases". My colleagues and I have found, though, that when a %d descriptor is used to print a char variable the result is as though a %c descriptor had been used -- printf and boost::format don't produce the same result. That is: int ii(42); char cc(42); printf( "Using printf: ii=%d, cc=%d\n", ii, cc ); cout << boost::format( "Using boost::format: ii=%d, cc=%d" ) % ii % cc << endl; Produces: Using printf: ii=42, cc=42 Using boost::format: ii=42, cc=* So, it seems that boost::format deduces the format to be used for outputting cc from its type and ignores the format explicitly requested in the format. Is this working as intended? If so the documentation seems to me to be misleading. I also note that: cout << boost::format( "As chars: ii=%c, cc=%c" ) % ii % cc << endl; Produces: As chars: ii=4, cc=* That is: the %c descriptor causes the value of ii (42) to be truncated to a single char. Also something of a surprise. My tests were carried out using boost 1.34.1 and Visual Studio 2005 on Windows. Cheers, Daniel.

2 2

[FileSystem] Linker Error on OS X with ICC - common symbols not allowed with MH_DYLIB
by Mike Jackson 30 Jan '08

30 Jan '08

I am trying to compile some code into a dynamic library and I am getting the following linker errors: Linking CXX shared library Bin/libLibTest.dylib xilibtool: executing 'libtool' ld: common symbols not allowed with MH_DYLIB output format with the - multi_module option CMakeFiles/LibTest.dir/LibTest.o definition of common __ZGVZN5boost10filesystem12initial_pathINS0_10basic_pathISbIwSt11char_tr aitsIwESaIwEENS0_12wpath_traitsEEEEERKT_vE9init_path (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZGVZN5boost10filesystem12initial_pathINS0_10basic_pathISsNS0_11path_tr aitsEEEEERKT_vE9init_path (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZGVZN5boost10filesystem6detail14remove_all_auxINS0_10basic_pathISbIwSt 11char_traitsIwESaIwEENS0_12wpath_traitsEEEEEmRKT_E7end_itr (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZGVZN5boost10filesystem6detail14remove_all_auxINS0_10basic_pathISsNS0_ 11path_traitsEEEEEmRKT_E7end_itr (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZZN5boost10filesystem12initial_pathINS0_10basic_pathISbIwSt11char_trai tsIwESaIwEENS0_12wpath_traitsEEEEERKT_vE9init_path (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZZN5boost10filesystem12initial_pathINS0_10basic_pathISsNS0_11path_trai tsEEEEERKT_vE9init_path (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZZN5boost10filesystem6detail14remove_all_auxINS0_10basic_pathISbIwSt11 char_traitsIwESaIwEENS0_12wpath_traitsEEEEEmRKT_E7end_itr (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZZN5boost10filesystem6detail14remove_all_auxINS0_10basic_pathISsNS0_11 path_traitsEEEEEmRKT_E7end_itr (size 16) libtool: internal link edit command failed make[2]: *** [Bin/libLibTest.dylib] Error 1 make[1]: *** [CMakeFiles/LibTest.dir/all] Error 2 make: *** [all] Err This is on OS X 10.4.11 with Intel C++ compiler version 10.1.007. Maybe I am not using the boost file_system library correctly? A simple reproducible case is to just try to create a library containing any code that includes boost/filesystem/operations.hpp. The same code works on gcc on OS X 10.4.11 (Xcode 2.5 tool set) -- Mike Jackson imikejackson & gmail * com

1 1

[FileSystem] Linker Error on OS X with ICC - common symbols not allowed with MH_DYLIB
by Mike Jackson 30 Jan '08

30 Jan '08

I am trying to compile some code into a dynamic library and I am getting the following linker errors: Linking CXX shared library Bin/libLibTest.dylib xilibtool: executing 'libtool' ld: common symbols not allowed with MH_DYLIB output format with the - multi_module option CMakeFiles/LibTest.dir/LibTest.o definition of common __ZGVZN5boost10filesystem12initial_pathINS0_10basic_pathISbIwSt11char_tr aitsIwESaIwEENS0_12wpath_traitsEEEEERKT_vE9init_path (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZGVZN5boost10filesystem12initial_pathINS0_10basic_pathISsNS0_11path_tr aitsEEEEERKT_vE9init_path (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZGVZN5boost10filesystem6detail14remove_all_auxINS0_10basic_pathISbIwSt 11char_traitsIwESaIwEENS0_12wpath_traitsEEEEEmRKT_E7end_itr (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZGVZN5boost10filesystem6detail14remove_all_auxINS0_10basic_pathISsNS0_ 11path_traitsEEEEEmRKT_E7end_itr (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZZN5boost10filesystem12initial_pathINS0_10basic_pathISbIwSt11char_trai tsIwESaIwEENS0_12wpath_traitsEEEEERKT_vE9init_path (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZZN5boost10filesystem12initial_pathINS0_10basic_pathISsNS0_11path_trai tsEEEEERKT_vE9init_path (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZZN5boost10filesystem6detail14remove_all_auxINS0_10basic_pathISbIwSt11 char_traitsIwESaIwEENS0_12wpath_traitsEEEEEmRKT_E7end_itr (size 16) CMakeFiles/LibTest.dir/LibTest.o definition of common __ZZN5boost10filesystem6detail14remove_all_auxINS0_10basic_pathISsNS0_11 path_traitsEEEEEmRKT_E7end_itr (size 16) libtool: internal link edit command failed make[2]: *** [Bin/libLibTest.dylib] Error 1 make[1]: *** [CMakeFiles/LibTest.dir/all] Error 2 make: *** [all] Err This is on OS X 10.4.11 with Intel C++ compiler version 10.1.007. Maybe I am not using the boost file_system library correctly? A simple reproducible case is to just try to create a library containing any code that includes boost/filesystem/operations.hpp. The same code works on gcc on OS X 10.4.11 (Xcode 2.5 tool set) Thanks -- Mike Jackson imikejackson & gmail * com

1 0

Flyweight library
by Martin Fisher 30 Jan '08

30 Jan '08

Took a look at the flyweight library. I'm very much a beginner - so not a formal review, just a couple of comments: I wrote a very simple test program to try flyweight. In essence: vector<boost::flyweight<string> > vec; struct Insert { void operator()(string s) { vec.push_back(boost::flyweight<string>(s)); //vec.push_back(s); } }; void Test() { fstream f("d:\\bible12.txt", ios_base::in); { boost::progress_timer t; for_each(istream_iterator<string>(f), istream_iterator<string>(), Insert()); } } This fails to compile with Borland Turbo C++ (internal compiler error) Under MS Visual C++ (Express 2008) it compiles ok. There is quite a performance hit over a standard vector<string> - 6s -> 80s in debug and 101s in release? From the docs I'd expected to just use copy and back_inserter? However, the showstopper for me at present is this crashes with: Managed Debugging Assistant 'FatalExecutionEngineError' has detected a problem in 'd:\Users\Martin\Documents\Visual Studio 2008\Projects\fly\Debug\fly.exe'. Additional Information: The runtime has encountered a fatal error. The address of the error was at 0x79e7352e, on thread 0x15d0. The error code is 0xc0000005. This error may be a bug in the CLR or in the unsafe or non-verifiable portions of user code. Common sources of this bug include user marshaling errors for COM-interop or PInvoke, which may corrupt the stack. Windows has triggered a breakpoint in fly.exe. This may be due to a corruption of the heap, which indicates a bug in fly.exe or any of the DLLs it has loaded. This may also be due to the user pressing F12 while fly.exe has focus. The output window may have more diagnostic information. On termination of the program. Have I misunderstood the usage of flyweight, or is there a problem here? Martin

2 2

boost datetime 1_32 like construction
by Chris_AC 30 Jan '08

30 Jan '08

Please, could someone explain me how i could construct a date like it was possible in boost version 1_32 (date d(2000,1,10); date d("2000-1-10")...) in 1_34 without a cascade of necessary code changes? Thanx a lot Chris -- View this message in context: http://www.nabble.com/boost-datetime-1_32-like-construction-tp15163613p1516… Sent from the Boost - Users mailing list archive at Nabble.com.

1 0

Type_traits: is_convertible and std::pair problem
by cp now 30 Jan '08

30 Jan '08

The type_traits library gives me somewhat erroneous answers when dealing with pairs of pairs. The following code produces the errors below, but interestingly, the BOOST_ASSERT actually succeeds. It seems is_convertible thinks a pair<pair<int, int>, int> is convertible to a plain old pair<int, int>, but the compiler (and this coder) takes a different view... #include <utility> #include <boost/assert.hpp> #include <boost/type_traits/is_convertible.hpp> std::pair<int, int> go(std::pair<int, int> p) { return p; } int main() { BOOST_STATIC_ASSERT(( boost::is_convertible< std::pair< std::pair<int, int>, int >, std::pair<int, int> >::value )); std::pair<std::pair<int, int>, int> p1 = std::make_pair(std::make_pair(1,2),3); std::pair<int, int> p2 = go(p1); return 0; } $ g++-4.1.1 test.cpp -I/usr/include/boost-1_33_1 /home/vsekhar/gcc-4.1.1/lib/gcc/i686-pc-cygwin/4.1.1/../../../../include/c++/4.1.1/bits/stl_pair.h: In constructor 'std::pair<_T1, _T2>::pair(const std::pair<_U1, _U2>&) [with _U1 = std::pair<int, int>, _U2 = int, _T1 = int, _T2 = int]': test.cpp:25: instantiated from here /home/vsekhar/gcc-4.1.1/lib/gcc/i686-pc-cygwin/4.1.1/../../../../include/c++/4.1.1/bits/stl_pair.h:90: error: cannot convert 'const std::pair<int, int>' to 'int' in initialization The compiler appears to be attempting a piecewise conversion of the contents of the pair, hence the error about converting pair<int, int> to 'int' rather than an error about converting pair<pair<int, int>, int> to pair<int, int>. Is there a method of converting that is_convertible has in mind when it returns true for the aforementioned conversion? I'm testing here for simple implicit conversion... -v

3 3

Boost Thread: condition.wait()
by Kesseli Pascal 30 Jan '08

30 Jan '08

Hi everyone Recently I was trying to synchronize one of my functions using the following code: // write own data to shared vector... // ... if (++numberOfReadyThreads < numberOfInvolvedThreads) { allChargingDataReady.wait(lock); return; } numberOfReadyThreads = 0; // Only the last thread enters this section. // write data to file... allChargingDataReady.singal_all(); The idea is that all threads submit their data using this function and then wait before reading in the next set of data until all threads have submitted their data. The last thread to submit his data is the one who has to write the collected data to a file. Using this structure, I find it very simple to realize this behavior. However, I know from programming with Java that the VM there sometimes awakens one's threads without any reason, which means that I would have to realize my condition like this instead: // ... while(numberOfReadyThreads < numberOfInvolvedThreads) { allChargingDataReady.wait(lock); } // ... Implementing the same behavior using this snippet is much more complicated though and I would rather avoid it if possible. And that leads us right away to my question: Is the while()-workaround using Boost & C++ needed as well as in Java? Or can I use the much simpler if()-version? Thanks for any reply and best regards Pascal No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.12/1245 - Release Date: 26.01.2008 15:45

2 1

How to compile Boost.Thread with BOOST_HAS_WINTHREADS
by anthony kelly 30 Jan '08

30 Jan '08

Hi Boost Users, I am trying to compile Boost.Thread with BOOST_HAS_WINTHREADS. I compile the library by going to "\libs\thread\build" and running "bjam toolset=gcc-nocygwin -sBOOST_HAS_WINTHREADS=1", but whenever I try to use the library I get undefined references to pthread functions, so I think the macro BOOST_HAS_WINTHREADS is not being defined. Is there a problem with the way I am defining the macro? Is there another way I can try? Thank you, Anthony

1 0

Boost::Thread constructor
by anthony kelly 30 Jan '08

30 Jan '08

Hello Boost Users, I would like to implement a simple threaded class like this: class C { public: void Start(); void Stop(); private: bool running; boost::thread t; void ThreadJob(); } void C::Start() { running = true; t = boost::thread(&C::ThreadJob); } void C::Stop() { running = false; t.join(); } void C::ThreadJob() { while(running); } However, the syntax for this line is wrong: t = boost::thread(&C::ThreadJob); The only examples I can find show starting the thread at the same time it is defined! Is it possible to define the thread as a class member, and start it later? If so, what would the syntax for this line be? If not, can you suggest an alternative structure? Thank you, Anthony

3 4