August 2004 - Boost-users - lists.boost.org

can the boost multi-array be easily extended to std::map's?
by Steven L. Scott 24 Aug '04

24 Aug '04

I'm working on an application (a data analysis system built in C++) for which it would be helpful to have nested (multidimensional) containers other than ordinary arrays. I have defined a generic 'data' class which I like to store in std::vector<data *>'s. For a very simple example, a 'data' might be a double representing a student's score on an exam, or in more complex settings it might be some sort of spatial map, or a multidimensional set of records for a medical patient. I am interested in structures where 'data' is nested across multiple levels. For example, test scores are nested within students, students nested within teachers, nested within school districts, etc. For a single layer of nesting a std::map<std::string, std::vector<data *> > seems to be an ideal way to store such data, largely because text strings can be used to identify subjects: dat["johnny"] // returns a std::vector of pointers to johnny's test scores. This is often the way that data are stored in files to be analyzed. I'm looking for some sort of C++ container that is more convenient for multiply nested data than std::map<std::string, std::map<std::string .... , std::vector<data *> > > ... >, but which will allow me to write expressions like: dat["LAUSD"]["Central High"]["Ms. Jones' Class"]["Johnny"] // same vector as above. Can something like the Boost multi-array package be extended to handle this?

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problems compiling example files
by MarC 24 Aug '04

24 Aug '04

I suppose, it's a begginer's linux problem but I didn't found the answer neither in the documentation nor in the internet forums... After installing boost on my system (see how at the end of this email), I wanted to compile simple_ls.cpp, the filesystem example. everything works when creating the .o but when linking a lot of undefined references arised. What have I done wrong? g++ -c simple_ls.cpp [marc@localhost ls]$ g++ -c simple_ls.cpp [marc@localhost ls]$ ls ls/ simple_ls.cpp* simple_ls.o [marc@localhost ls]$ g++ simple simple_ls.cpp simple_ls.o [marc@localhost ls]$ g++ simple_ls.cpp -o simple_ls /tmp/ccjMYBxo.o(.text+0x19): In function `main': : undefined reference to `boost::filesystem::initial_path()' /tmp/ccjMYBxo.o(.text+0x44): In function `main': : undefined reference to `boost::filesystem::native(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)' /tmp/ccjMYBxo.o(.text+0x55): In function `main': : undefined reference to `boost::filesystem::path::path[in-charge](char const*, bool (*)(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&))' /tmp/ccjMYBxo.o(.text+0x64): In function `main': : undefined reference to `boost::filesystem::system_complete(boost::filesystem::path const&)' /tmp/ccjMYBxo.o(.text+0x119): In function `main': : undefined reference to `boost::filesystem::exists(boost::filesystem::path const&)' /tmp/ccjMYBxo.o(.text+0x13c): In function `main': : undefined reference to `boost::filesystem::path::native_file_string() const' /tmp/ccjMYBxo.o(.text+0x1bf): In function `main': : undefined reference to `boost::filesystem::is_directory(boost::filesystem::path const&)' /tmp/ccjMYBxo.o(.text+0x1e2): In function `main': : undefined reference to `boost::filesystem::path::native_directory_string() const' /tmp/ccjMYBxo.o(.text+0x291): In function `main': : undefined reference to `boost::filesystem::is_directory(boost::filesystem::path const&)' /tmp/ccjMYBxo.o(.text+0x2ca): In function `main': : undefined reference to `boost::filesystem::path::leaf() const' /tmp/ccjMYBxo.o(.text+0x351): In function `main': : undefined reference to `boost::filesystem::path::leaf() const' /tmp/ccjMYBxo.o(.text+0x418): In function `main': : undefined reference to `boost::filesystem::path::leaf() const' /tmp/ccjMYBxo.o(.text+0x586): In function `main': : undefined reference to `boost::filesystem::path::native_file_string() const' /tmp/ccjMYBxo.o(.gnu.linkonce.t._ZN5boost10filesystem18directory_iteratorC1ERKNS0_4pathE+0x2d): In function `boost::filesystem::directory_iterator::directory_iterator[in-charge](boost::filesystem::path const&)': : undefined reference to `boost::filesystem::detail::dir_itr_init(boost::shared_ptr<boost::filesystem::detail::dir_itr_imp>&, boost::filesystem::path const&)' /tmp/ccjMYBxo.o(.gnu.linkonce.t._ZNK5boost10filesystem18directory_iterator11dereferenceEv+0xd): In function `boost::filesystem::directory_iterator::dereference() const': : undefined reference to `boost::filesystem::detail::dir_itr_dereference(boost::shared_ptr<boost::filesystem::detail::dir_itr_imp> const&)' /tmp/ccjMYBxo.o(.gnu.linkonce.t._ZN5boost10filesystem18directory_iterator9incrementEv+0xd): In function `boost::filesystem::directory_iterator::increment()': : undefined reference to `boost::filesystem::detail::dir_itr_increment(boost::shared_ptr<boost::filesystem::detail::dir_itr_imp>&)' collect2: ld returned 1 exit status thank you in advance again. PS: my system is: [marc@localhost html]$ g++ -v Reading specs from /usr/lib/gcc-lib/i586-mandrake-linux-gnu/3.3.2/specs Configured with: ../configure --prefix=/usr --libdir=/usr/lib --with-slibdir=/lib --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --disable-checking --enable-long-long --enable-__cxa_atexit --enable-clocale=gnu --enable-languages=c,c++,ada,f77,objc,java,pascal --host=i586-mandrake-linux-gnu --with-system-zlib Thread model: posix gcc version 3.3.2 (Mandrake Linux 10.0 3.3.2-6mdk) And i've installed boost using these packages: Nombre: libboost1 Versión: 1.31.0-5mdk ‎/usr/lib/libboost_date_time.so.1 ‎/usr/lib/libboost_date_time.so.1.31.0 ‎/usr/lib/libboost_filesystem.so.1 ‎/usr/lib/libboost_filesystem.so.1.31.0 ‎/usr/lib/libboost_prg_exec_monitor.so.1 ‎/usr/lib/libboost_prg_exec_monitor.so.1.31.0 ‎/usr/lib/libboost_python.so.1 ‎/usr/lib/libboost_python.so.1.31.0 ‎/usr/lib/libboost_regex.so.1 ‎/usr/lib/libboost_regex.so.1.31.0 ‎/usr/lib/libboost_signals.so.1 ‎/usr/lib/libboost_signals.so.1.31.0 ‎/usr/lib/libboost_test_exec_monitor.so.1 ‎/usr/lib/libboost_test_exec_monitor.so.1.31.0 ‎/usr/lib/libboost_thread.so.1 ‎/usr/lib/libboost_thread.so.1.31.0 ‎/usr/lib/libboost_unit_test_framework.so.1 ‎/usr/lib/libboost_unit_test_framework.so.1.31.0 ‎/usr/share/doc/libboost1-1.31.0 ‎/usr/share/doc/libboost1-1.31.0/LICENSE_1_0.txt Nombre: libboost1-devel Versión: 1.31.0-5mdk Archivos: ‎/usr/include/boost ‎/usr/include/boost/aligned_storage.hpp ‎/usr/include/boost/any.hpp ‎/usr/include/boost/array.hpp ‎/usr/include/boost/assert.hpp ‎/usr/include/boost/bind ‎/usr/include/boost/bind.hpp ‎/usr/include/boost/bind/apply.hpp ‎/usr/include/boost/bind/arg.hpp ‎/usr/include/boost/bind/bind_cc.hpp ‎/usr/include/boost/bind/bind_mf_cc.hpp ‎/usr/include/boost/bind/bind_template.hpp ‎/usr/include/boost/bind/make_adaptable.hpp ‎/usr/include/boost/bind/mem_fn_cc.hpp ‎/usr/include/boost/bind/mem_fn_template.hpp ‎/usr/include/boost/bind/mem_fn_vw.hpp ‎/usr/include/boost/bind/placeholders.hpp ‎/usr/include/boost/bind/protect.hpp ‎/usr/include/boost/blank.hpp ‎/usr/include/boost/blank_fwd.hpp ‎/usr/include/boost/call_traits.hpp ... /usr/lib/libboost_date_time.so ‎/usr/lib/libboost_filesystem.so ‎/usr/lib/libboost_prg_exec_monitor.so ‎/usr/lib/libboost_python.so ‎/usr/lib/libboost_regex.so ‎/usr/lib/libboost_signals.so ‎/usr/lib/libboost_test_exec_monitor.so ‎/usr/lib/libboost_thread.so ‎/usr/lib/libboost_unit_test_framework.so ‎/usr/share/doc/libboost1-devel-1.31.0 ‎/usr/share/doc/libboost1-devel-1.31.0/README ‎/usr/share/doc/libboost1-devel-1.31.0/boost.css ‎/usr/share/doc/libboost1-devel-1.31.0/c++boost.gif Nombre: libboost1-static-devel Versión: 1.31.0-5mdk ‎/usr/lib/libboost_date_time.a ‎/usr/lib/libboost_filesystem.a ‎/usr/lib/libboost_prg_exec_monitor.a ‎/usr/lib/libboost_python.a ‎/usr/lib/libboost_regex.a ‎/usr/lib/libboost_signals.a ‎/usr/lib/libboost_test_exec_monitor.a ‎/usr/lib/libboost_unit_test_framework.a

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boost.graph question concerning edge descriptor details
by Jeff Holle 23 Aug '04

23 Aug '04

I'm using gcc v3.4.1 and boost_CVS captured on Tue Jun 29 05:25:17 EDT 2004. I'm developing a boost.graph application that must deal with multiple graphs. The following typedefs describe how its using boost.graph: typedef boost::adjacency_list<boost::vecS,boost::vecS,boost::bidirectionalS> GraphT; typedef boost::shared_ptr<GraphT> GraphPtr; typedef boost::graph_traits <GraphT>::vertex_descriptor Vertex; typedef boost::graph_traits <GraphT>::edge_descriptor Edge; In addition, I have various maps that must act as a "bridge" between these graphs. I'm using the following typedefs as keys in such maps: typedef std::pair<GraphPtr,Vertex> ExternalVertex; typedef std::pair<GraphPtr,Edge> ExternalEdge; I've used ExternalVertex successfully in two different maps. Now I'm having trouble populating the first map that uses ExternalEdge. The compiler warnings that I'm getting sugguest that Edge does have an "operator<" method. Specifically its: error: no match for 'operator<' in '__x->std::pair<GraphPtr, Edge>::second < __y->std::pair<GraphPtr, Edge>::second' I'm wondering why Edge is different from Vertex. As you can see, as I've defined GraphT, both edge and vertex properties should be no_property. Any guidance that assists me to, at worst case, write a Compare operator for my "map<ExternalEdge,...>" containers would be appreciated.

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Removing edges/vertices from a boost.graph object
by Jeff Holle 23 Aug '04

23 Aug '04

I'm using boost.graph captured from CVS on Tue Jun 29 05:25:17 EDT 2004. The type of graph that I'm using is: typedef boost::adjacency_list<boost::vecS,boost::vecS,boost::bidirectionalS> GraphT; I need to trim vertex/edges that was moved to other graphs. I can't seem to do this. Calling remove_vertex appears to be a NOOP. The last thing I tried was: clear_vertex(*vi); remove_vertex(*vi); The gerdemann.cpp example gave me this idea. The clear_vertex did the job that I need in that the necessary edges disappeared. However, the remove_vertex still does not remove the vertexs. What do I have to do to get the ability to clear vertices?

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boost::thread
by Raja 23 Aug '04

23 Aug '04

Does using thread classes from boost need additional library files other than header files ? I am getting the following error when I use the thread class: /usr/include/c++/3.2.3/bits/stl_heap.h:188: undefined reference to `boost::thread::thread[in-charge](boost::function0<void, std::allocator<boost::function_base> > const&)' I also see 'libboost_thread-gcc-mt-d-1_31.so.1.3.0' library under boost/bin/... Does this have to be used ? Thanks in advance Raja

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boost::filesystem problems
by Carlo Wood 23 Aug '04

23 Aug '04

A few months ago I started to write my first multi-platform application. In the hope to be shielded from all kinds of filesystem specific issues, I started to use boost - also for the first time - mainly because of of boost::filesystem. However - I have found that it doesn't shield me from a LOT of filesystem specific things. In the meantime I was in the need of writing six additional functions that are filesystem specific: std::string native_file_string(fs::path const&); void copy_file(fs::path const& source_file, fs::path const& target_file); void chmod(fs::path const& filename, bool readonly); bool is_readonly(fs::path const& filename); void rename_file(fs::path const& source_file, fs::path const& target_file); size_t get_file_size(fs::path const& filename); Today I ran into a very serious problem. Hopefully it is just me who is making a stupid mistake (however unlikely that may sound ;) but it sure seems like a huge bug in boost::filesystem of a magnitude that not only amazes me but will also force me to stop using boost::filesystem if this is true. The reason that I didn't find this problem earlier in the pasts months is because so far I've done all development on GNU/Linux - and only recently have started to actually try and get things to work on cygwin. The reason I subscribed to this list is in the hope to find Beman here, is he reading this list? My hope is to start a public discussion about boost::filesystem - problems, improvements, missing features etc. I will sent a separate mail for the 'serious bug' that I just mentioned, because it isn't 100% sure yet that this is actually a bug ;). -- Carlo Wood <carlo(a)alinoe.com>

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Build with BCB6 failed
by Steffen Rauh 21 Aug '04

21 Aug '04

Hello, creating a custom build, I get lots of compiler errors during Boost.Python compilation. Some of these compiler errors are: c:\...\boost_1_31_0\libs\python\build\../src/numeric.cpp: Error E2231 C:\...\boost_1_31_0\boost/python/detail/value_is_shared_ptr.hpp 14: Member value_is_shared_ptr<X_>::value cannot be used without an object. Error E2299 C:\...\boost_1_31_0\boost/python/detail/value_is_shared_ptr.hpp 14: Cannot generate template specialization from 'mpl::bool_<C_>' Error E2040 C:\...\boost_1_31_0\boost/python/detail/value_is_shared_ptr.hpp 14: Declaration syntax error These error messages repeat in a lot of other files. Sometimes the compiler aborts compilation because of too many errors or warnings. The rest of boost seems to compile fine. Does anybody have an idea on how to solve this problem? Is this difficulty already known? I tried to compile with Python 2.3 at first but switched back to Python 2.2 because I read somewhere that there may be some problems with this version. But it did not solve the problem. I already tried to compile the current CVS Snapshot but it did not change a thing. My configuration is: - Python 2.2 - Boost 1.31.0 - bjam 3.1.10 - Windows XP - Borland C++ Builder 6 Personal Building Boost with: c:\...\boost_1_31_0>bjam -sTOOLS=borland -sPYTHON_ROOT=c:\...\python22 install I would appreciate any suggestions. Regards, Steffen Rauh

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boost erreur
by adel.essafi 20 Aug '04

20 Aug '04

hi list I am using boost to build a small tool that generate a (GRAPHICAL) graph showing dependecies between files ;) I donc guess why g++ returns to me this error. any input will be helpful thanks Ps : excuse me. I will copy all the source file and the error. you can find it a long. #include <qapplication.h> #include <qdir.h> #include <qcanvas.h> #include <iostream.h> #include <vector.h> #include <fstream.h> #include <string.h> #include <fstream> #include <string> #include <iostream> #include <algorithm> #include <string> #include <boost/config.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/property_map.hpp> #include <qstring.h> using namespace std; using namespace boost; enum vertex_first_name_t { vertex_first_name }; namespace boost { BOOST_INSTALL_PROPERTY(vertex, first_name); } template <class EdgeIter, class Graph> void who_owes_who(EdgeIter first, EdgeIter last, const Graph& G) { // Access the propety acessor type for this graph typedef typename property_map<Graph, vertex_first_name_t> ::const_type NamePA; NamePA name = get(vertex_first_name, G); typedef typename boost::property_traits<NamePA>::value_type NameType; NameType src_name, targ_name; while (first != last) { src_name = boost::get(name, source(*first,G)); targ_name = boost::get(name, target(*first,G)); cout << src_name << " owes " << targ_name << " some money" << endl; ++first; } } int main(int argc,char **argv) { // Create the graph, and specify that we will use std::string to // store the first name's. typedef adjacency_list<vecS, vecS, directedS,property<vertex_first_name_t, QString> > MyGraphType; MyGraphType G; property_map<MyGraphType, vertex_first_name_t>::type name= get(vertex_first_name, G); QApplication a( argc, argv ); QCanvas c; QDir dir (".") ; int filesnum=0; QStringList lst = dir.entryList( "*.cpp; *.h" ); for ( QStringList::Iterator it = lst.begin(); it != lst.end(); ++it ) { boost::graph_traits<MyGraphType>::vertex_descriptor v; name[v]=*it; add_vertex(v,G); cerr << *it << endl; filesnum++; } return 0; } g++ -o filetree main.cpp -I /usr/lib/qt-3.1/include -L /usr/lib/qt-3.1/lib -lqt Dans le fichier inclus à partir de /usr/include/c++/3.3.2/backward/iostream.h:31, à partir de main.cpp:4: /usr/include/c++/3.3.2/backward/backward_warning.h:32:2: attention : #warning This file includes at least one deprecated or antiquated header. Please consider using one of the 32 headers found in section 17.4.1.2 of the C++ standard. Examples include substituting the <X> header for the <X.h> header for C++ includes, or <sstream> instead of the deprecated header <strstream.h>. To disable this warning use -Wno-deprecated. main.cpp: Dans function « int main(int, char**) »: main.cpp:67: error: invalid initialization of reference of type 'const boost::property<vertex_first_name_t, QString, boost::no_property>&' from expression of type 'size_t' /usr/include/boost/graph/detail/adjacency_list.hpp:1916: error: in passing argument 1 of `typename Config::vertex_descriptor boost::add_vertex(typename Config::vertex_property_type&, boost::vec_adj_list_impl<G, C, B>&) [with Graph = boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, boost::property<vertex_first_name_t, QString, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, Config = boost::detail::adj_list_gen<boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, boost::property<vertex_first_name_t, QString, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, boost::vecS, boost::vecS, boost::directedS, boost::property<vertex_first_name_t, QString, boost::no_property>, boost::no_property, boost::no_property, boost::listS>::config, Base = boost::directed_graph_helper<boost::detail::adj_list_gen<boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, boost::property<vertex_first_name_t, QString, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, boost::vecS, boost::vecS, boost::directedS, boost::property<vertex_first_name_t, QString, boost::no_property>, boost::no_property, boost::no_property, boost::listS>::config>]' gmake: *** [filetree] Erreur 1 *** échec *** Accédez au courrier électronique de La Poste : www.laposte.net ; 3615 LAPOSTENET (0,34/mn) ; tél : 08 92 68 13 50 (0,34/mn)

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RE: [Boost-users] New design proposal for boost::filesystem
by Rozental, Gennadiy 20 Aug '04

20 Aug '04

> I propose the following design. The aim of boost::filesystem > should be to support the following coding idiom: I don't think this is a proper forum for this. Try development mailing list Gennadiy.

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RE: [Boost-users] New design proposal for boost::filesystem
by Ben Hutchings 20 Aug '04

20 Aug '04

Carlo Wood <carlo(a)alinoe.com> wrote: > I propose the following design. The aim of boost::filesystem should > be to support the following coding idiom: > > * The programmer should take care to only handle two types of paths > in his application: > > 1) Complete paths > 2) Relative paths Are there any other types? > * The programmer will have to specifically tell the libary when a > constructed path is 'native' and when not. <snip> Sounds reasonable. > I propose two design changes: > > 1) 'native' is now not only a representation, but an *internal > state* of fs::path. (this has no effect on the representation > as returned by fs::path::string()). > 2) All 'complete' paths are automatically marked as 'native'. > > Examples, the following code is legal: > > fs::path p1("C:\foo\a.exe", native); // Fails on linux, > // success on windows. You have that backwards. "\f" and "\a" are not valid in a filename in Win32. Now if those backslashes are changed to "\\" this will work on Win32. Either version of the name will work on Linux because all characters except "\0" are valid in a Unix filename. > fs::path p2("/usr/src/a.out, native); // Fails on windows, > // success on linux. That should work on Windows too because "/" is supported as an alternative to "\\". <snip> > But in case more than one 'working' directory seems needed > then we can add support for that too by allowing to > construct paths with a reference to the (complete/native) > working directory. Ie, > > fs::path home_base(...); > // ... > > fs::path runtime_rcfile(home_base); > // ... > > runtime_rcfile = "myapplication/config/runtime/rc"; > > which is then relative to `home_base' instead of > a single, global 'working directory' (as now returned > by fs::current_path()). <snip> That doesn't seem right to me. Assignment should overwrite the old value rather than combining with it.

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