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xml_grammar
by Becky Bendick 14 Jan '05

14 Jan '05

I'm trying to install boost1.32 using the prebuilt bjam for mac darwin, but it seems to hang on darwin-C++-action bin/boost/libs/serialization/build/libboost_serialization.a/darwin/ release/xml_grammar.o or perhaps this just takes hours, which seems unlikely. What am I doing wrong, and how do I fix it? Thanks, Becky ------------------------------------------------------------------------ ---------------------- Rebecca Bendick, Ph.D. Bullard Laboratories University of Cambridge Madingley Road CAMBRIDGE CB3 0EZ United Kingdom bendick(a)esc.cam.ac.uk

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Multithreaded Signal Library
by Stephen torri 14 Jan '05

14 Jan '05

Since it has been advise by many people in the past that retrofitting software is troublesome and expense. I am looking at the issues of redesigning the signals library from scratch to keep the same interface. Before providing a new solution to consider I have a few questions. Is the relationship of signals to slots 1 to N where N = 0 to some value? From what I have read I believe this is true. Since signals are not copyable? N processes desiring to signal the M slots (N = 0 to some value N, M = 0 to some value M) will have to do it through the same signal object if the processes are of the same type (class has an signal object as a variable). Right? The second question comes from my initial understanding of the signals library. I was thinking about this scenario: There is a class call Cart which has a signal boost::signal<void()> in_Parking_Lot in it. Since a store will have multiple Carts for customers to use the owner has programmed his carts to signal the front desk computer when they are moved out of the store. class Cart { private: boost::signal<void()> in_Parking_Lot; public: void init (FrontDesk& fd) { in_Store = true; in_Parking_Lot.connect(fd); void process () { for (;;) { Check location (If in store set in_Store = true vice versa if not). if ( ! in_Store ) { in_Parking_Lot(); } } }; So if I have a very small shop with 50 Carts, all 50 Carts be using the same signal object to alert the front desk. If I had a big computer with 51 cpus (50 Carts and 1 FrontDesk) to run each process I have a race condition. Which process gets to alert the front desk when? >From what I understand the relationship of signals to slots is (1:N) where N is 0 to some number. So I have to have some structure in place so that I keep things safe (e.g. no race conditions or starvation) while maintaining throughput when the 50 processes try to send a signal at the same tiem. So given my example I was wondering what are the properties that I need to maintain? For example should each call to the signal's operator() function be blocking (each signaling process must update all the slots listening for the signal before returning) or non-blocking (some other process handles updating the slots while the signaling process returns back to work right away). The final question is that if indeed the relationship of signals to slots is 1:N then the multi-threading problems begins to surface more predominately. That is T threads, where T is a Cart object, use 1 signal to notify N slots. We have a restricted resource, the 1 signal, to update N slots at various times during the lifetime of the T threads. Is this the problem of using the signal library with multiple threads? I will leave things there for now and await your response. Stephen

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newbie question: large multiarray in a mult-file project
by M L 13 Jan '05

13 Jan '05

Hi, I need to declare a large multiarray in a multi-class project, something in the order of 10,000 x 300 x sizeof(a struct of 48 byte), I need to put the matrix in a header file so that other classes can see it. would it be a good idea to put all of the following lines in a header file? or the memory allocation should really be done in a .cpp file while leaving a pointer of some sort in the header? in other words, what would be a better way of declaring a large multiarray in a multi-file project? typedef boost::multi_array<xystruct, 2> xyType; //xystruct is a struct of 6 doubles xyType xy(boost::extents[10000][300]); many thanks mike

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RE: [Boost-users] error in boost/graph/fruchterman_reingold.hpp
by John Wilkinson 13 Jan '05

13 Jan '05

This one works, correcting the "grpah" typo: http://boost-consulting.com/boost/libs/graph/doc/fruchterman_reingold.ht ml -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Welson Sun Sent: Wednesday, January 12, 2005 10:04 PM To: boost-users(a)lists.boost.org Subject: RE: [Boost-users] error in boost/graph/fruchterman_reingold.hpp The link you provided is 404 error. -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Jamie Wilkinson Sent: Wednesday, January 12, 2005 2:16 AM To: Boost-users(a)lists.boost.org Subject: [Boost-users] error in boost/graph/fruchterman_reingold.hpp The doc at http://boost-consulting.com/boost/libs/grpah/doc/fruchterman_reingold.ht ml suggests that there is a 4 argument version of the function, taking only the graph, a position map, width and height; but attempts to compile such a function against the headers from the latest CVS results in a compile error: error: no matching function for call to ` fruchterman_reingold_force_directed_layout(Umbrella::Document&, Umbrella::View::load_from_document()::PositionMap&, double&, double&)' Removing the typenames Param, Tag, and Rest from lines 371-372 of the header allows the compile to continue. Index: boost/graph/fruchterman_reingold.hpp =================================================================== RCS file: /cvsroot/boost/boost/boost/graph/fruchterman_reingold.hpp,v retrieving revision 1.5 diff -u -c -r1.5 fruchterman_reingold.hpp cvs diff: conflicting specifications of output style *** boost/graph/fruchterman_reingold.hpp 29 Dec 2004 16:53:05 -0000 1.5 --- boost/graph/fruchterman_reingold.hpp 12 Jan 2005 09:18:16 -0000 *************** *** 368,375 **** params); } ! template<typename Graph, typename PositionMap, typename Dim, typename Param, ! typename Tag, typename Rest> void fruchterman_reingold_force_directed_layout(const Graph& g, PositionMap position, --- 368,374 ---- params); } ! template<typename Graph, typename PositionMap, typename Dim> void fruchterman_reingold_force_directed_layout(const Graph& g, PositionMap position, _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Date-Time question on seconds since epoch
by Bill Lear 13 Jan '05

13 Jan '05

I'd like to determine the total number of seconds between a date and the epoch ('00:00:00 1970-01-01 UTC'), The date can be in a timezone that has daylight savings. The date should be converted to UTC, with appropriate daylight savings adjustments made, and then the epoch subtracted from it. This should mirror the unix GNU 'date' utility, which can be run as: % TZ="America/New_York" date --date='2004-10-04 12:14:32' +%s 1096906472 I've looked at the doc, but it's not clear how to do this. Could someone give me a few pointers, please? Thanks. Bill

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VC7.1 compile errors using boost::multi_array with template functions
by Thomas A. Seidel 13 Jan '05

13 Jan '05

Hello everybody, I wrote 2 simple template functions for printing the content of arrays which model boost::multi_array. Template functions are necessary to be independent of the exact array type (multi_array_ref, subarrays, array_views and so on), dimension and element type. Here is the corresponding code snippet: ------------------------------------------------------- #include <cstddef> #include <iostream> #include <string> #include <boost/multi_array.hpp> template <typename T, std::size_t Dim, template <typename, std::size_t> class ArrayType> std::ostream& print(const ArrayType<T, Dim>& ma, std::ostream& os); template <typename T, template <typename, std::size_t> class ArrayType> std::ostream& print(const ArrayType<T, 1>& ma, std::ostream& os); template <typename T, template <typename, std::size_t> class ArrayType> inline std::ostream& print(const ArrayType<T, 1>& ma, std::ostream& os) { os << "| "; typename boost::multi_array<T, 1>::size_type ma_size = ma.size(); for (typename boost::multi_array<T, 1>::size_type i = 0 ; i < ma_size; i++) os << ma[i] << ' '; return os; } template <typename T, std::size_t Dim, template <typename, std::size_t> class ArrayType> inline std::ostream& print(const ArrayType<T, Dim>& ma, std::ostream& os) { os << std::string(Dim, '|') << ' '; typename boost::multi_array<T, Dim>::size_type ma_size = ma.size(); for (typename boost::multi_array<T, Dim>::size_type i = 0 ; i < ma_size; i++) { typename ArrayType<T, Dim>::const_reference row = ma[i]; print(row, os); } return os; } int main(int argc, char** argv) { boost::multi_array<unsigned int, 3> test(boost::extents[4][4][4]); for (unsigned int i = 0; i < 4; i++) for (unsigned int j = 0; j < 4; j++) for (unsigned int k = 0; k < 4; k++) test[i][j][k] = k; print(test, std::cout); std::cout << std::endl; print(test[0], std::cout); std::cout << std::endl; return 0; }; ------------------------------------------------------- The code compiles fine under Linux (Suse 9.1, gcc3.3.3) and upon execution produces the following (expected) output: ||| || | 0 1 2 3 | 0 1 2 3 | 0 1 2 3 | 0 1 2 3 || | 0 1 2 3 | 0 1 2 3 | 0 1 2 3 | 0 1 2 3 || | 0 1 2 3 | 0 1 2 3 | 0 1 2 3 | 0 1 2 3 || | 0 1 2 3 | 0 1 2 3 | 0 1 2 3 | 0 1 2 3 || | 0 1 2 3 | 0 1 2 3 | 0 1 2 3 | 0 1 2 3 However, compiling the above code with VC7.1 produces 5 errors caused by the wrong deduction of the template parameters (the corresponding build-log is attached - unfortunately only in german language because I do not have an english VC version available, but its highly technical stuff anyway). VC7 always deduces the 'ArrayType'-type for the template function wrong. The type VC7 uses for an instantiation is the direct base class (e.g. multi_array_ref instead of multi_array) instead of the actual argument type and in the end tries to call nonexistent member-functions and constructors. A search in the microsoft compiler-documentation didn't reveal a solution for my problem. So, is this a known bug/error/problem of VC7 and does anybody know an elegant workaround???? Thanks in advance!! Regards, Thomas

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Graph: 2 questions on property maps and subgraphs
by Andrea Olgiati 13 Jan '05

13 Jan '05

Hi, A couple of (newbie) questions on subgraphs and property maps: 1. I tried to re-run the example posted at http://lists.boost.org/MailArchives/boost-users/msg05889.php and I get a segfault whilst trying to assign name1[B1] - according to a follow-up message (http://lists.boost.org/MailArchives/boost-users/msg05891.php) that code snippet was supposed to be working fine. Am I doing something wrong? 2. Maybe it's another symptom of the same problem, but I am seeing runtime failures (invalid pointers) when I write code such as: > Graph *graph = wantFullGraph? rootGraph : subGraph; > MyPropertyMap mymap = get(my_type_t(), *graph); > for( v in all vertices in *graph) { > mymap[v] = blah; > } That is, after reading the docs my understanding is that if I pick up a property map from a (sub)graph, I can use the vertices in that (sub)graph to address into that map - everything should work fine provided that I am consistently using the same (sub)graph. Is this understanding correct? If so, I'm puzzled - the only way I can get this to work is to do: > Graph *graph = wantFullGraph? rootGraph : subGraph; > MyPropertyMap mymap = get(my_type_t(), *rootGraph); > for( v in all vertices in *graph) { > v1 = graph->local_to_global(v) > mymap[v1] = blah; > } I am using - gcc version 3.3.4 (pre 3.3.5 20040809) - Linux myhost 2.6.8-24.10-default #1 Wed Dec 22 11:54:27 UTC 2004 i686 i686 i386 GNU/Linux Can someone enlighten me. please? Thanks, Andrea

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Serialazation compilign under windows.
by Ken Perry 12 Jan '05

12 Jan '05

I am trying to compile Serialization with out cygwin but serialization and other libraries in boost give the error "#error wide char i/o not supported on this platform" When I try to compile under the xp pro Command line. Is there some way this and the other libraries can be compiled under Mingw even if wide char i/o is not supported I don't really need wide char i/o I just want a way to use serialization xml as my base file types under both linux and windows. Ken

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more matrix.hpp
by Becky Bendick 12 Jan '05

12 Jan '05

Here is a more detailed description of the error from the config.log /sw/include/boost/numeric/ublas/vector_expression.hpp:1837: error: due to a defect in the G++ 3.2 ABI, G++ has assigned the same mangled name to two different types In file included from /sw/include/boost/numeric/ublas/matrix.hpp:23, from conftest.cc:67: /sw/include/boost/numeric/ublas/matrix_expression.hpp:5156: error: due to a defect in the G++ 3.2 ABI, G++ has assigned the same mangled name to two different types Thanks again, Becky ------------------------------------------------------------------------ ---------------------- Rebecca Bendick, Ph.D. Bullard Laboratories University of Cambridge Madingley Road CAMBRIDGE CB3 0EZ United Kingdom bendick(a)esc.cam.ac.uk

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C++ Template Metaprogramming - Exercise 2-0
by Trask, Bruce (US SSA) 12 Jan '05

12 Jan '05

Hello, I am going through the book C++ Template Metaprogramming and wanted a sanity check on Exercise 2-0 from the book. My first question is: What would be a motivating example for why one would want a add_const_ref<T> metafunction that returned T if it was a reference and T const& otherwise? My second question is: How did I do? My guess is that the second crack is more correct. Here is crack one: My first crack at the exercise is below (my 2nd crack is below that) #include <iostream> #include <boost/type_traits/is_reference.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/static_assert.hpp> using namespace std; template<typename T, bool> struct add_const_ref { typedef T const& value_type; }; template<typename T> struct add_const_ref<T, true> { typedef T value_type; }; template<typename T> void func(typename add_const_ref<T, boost::is_reference<T>::value >::value_type t) { // .. do something } class BigClass { }; int main() { int i = 0; BOOST_STATIC_ASSERT((boost::is_same<add_const_ref<int&, boost::is_reference<int&>::value >::value_type, int&>::value)); BOOST_STATIC_ASSERT((boost::is_same<add_const_ref<int, boost::is_reference<int>::value >::value_type, int const&>::value)); func<int&>(i); BigClass myBigClass; func<BigClass>(myBigClass); return 0; } After taking a look at add_reference.hpp in boost I modified my answer to the one below: #include <iostream> #include <boost/type_traits/is_reference.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/static_assert.hpp> using namespace std; template<bool> struct const_ref_adder { template<typename T> struct result_ { typedef T const& value_type; }; }; template<> struct const_ref_adder<true> { template<typename T> struct result_ { typedef T value_type; }; }; template<typename T> struct add_const_ref { typedef typename const_ref_adder<boost::is_reference<T>::value >::template result_<T>::value_type value_type; }; template<typename T> void func(typename add_const_ref<T>::value_type t) { // .. do something } class BigClass { }; int main() { int i = 0; BOOST_STATIC_ASSERT((boost::is_same<add_const_ref<int&>::value_type, int&>::value)); BOOST_STATIC_ASSERT((boost::is_same<add_const_ref<int>::value_type, int const&>::value)); func<int&>(i); BigClass myBigClass; func<BigClass>(myBigClass); return 0; } Thanks in advance for your input, Bruce

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matrix.hpp usability
by Becky Bendick 12 Jan '05

12 Jan '05

Hi, I guess this is a 'newbie' question, so I apologize if the answer is obvious to everyone but me. I've just installed boost 1.31 on an apple powerpc using fink. However, when I run compile for the dependent software that needs the boost libraries, I get the following: checking for boost/numeric/ublas/matrix.hpp presence in /sw/include...... yes checking for boost/numeric/ublas/matrix.hpp usability...... no Is there something I can do to matrix.hpp to make it usable? I've confirmed that it exists in the right place, and isn't empty or anything. Thanks, Becky ------------------------------------------------------------------------ ---------------------- Rebecca Bendick, Ph.D. Bullard Laboratories University of Cambridge Madingley Road CAMBRIDGE CB3 0EZ United Kingdom bendick(a)esc.cam.ac.uk

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Serialization polymorphic iarchives & binary_object problem
by Sergey Skorniakov 12 Jan '05

12 Jan '05

Hello, All! This code: #include <fstream> #include <boost/archive/polymorphic_text_iarchive.hpp> #include <boost/archive/polymorphic_text_oarchive.hpp> #include <boost/archive/polymorphic_binary_iarchive.hpp> #include <boost/archive/polymorphic_binary_oarchive.hpp> #include <boost/serialization/binary_object.hpp> int main(int argc, char* argv[]) { { char testdata[4] = "asd"; std::ofstream os("test.txt", std::ios::binary); boost::archive::polymorphic_binary_oarchive ar(os); // boost::archive::polymorphic_text_oarchive ar(os); // boost::archive::text_oarchive ar(os); // boost::archive::binary_oarchive ar(os); ar & boost::serialization::make_binary_object(&testdata, sizeof(testdata)); assert(os.good()); } { char testdata[4] = " "; std::ifstream is("test.txt", std::ios::binary); assert(is.good()); boost::archive::polymorphic_binary_iarchive ar(is); // boost::archive::polymorphic_text_iarchive ar(is); // boost::archive::text_iarchive ar(is); // boost::archive::binary_iarchive ar(is); ar & boost::serialization::make_binary_object(&testdata, sizeof(testdata)); assert(is.good()); assert(testdata[0] == 'a'); } return 0; } does not work as expected - last assert failed. With text_iarchive/text_oarchive or binary_iarchive/binary_oarchive everything works fine. With polymorphic_text_archive another assert failed - is.good() returns false. I'm using VC 7.1 compiler. I had trying to compile this code with Intel 8.1 compiler but got errors, identical for polymorphic binary and text archives : Compiling with Intel(R) C++ 8.1 ...(Intel C++ Environment) TestPolyArchives.cpp C:\boost_1_32_0\boost/serialization/binary_object.hpp(43): error #308: function "boost::archive::polymorphic_oarchive::save_binary" is inaccessible ar.save_binary(m_t, m_size); ^ detected during: instantiation of "void boost::serialization::binary_object::save(Archive &, const unsigned int) const [with Archive=boost::archive::polymorphic_oarchive]" at line 90 of "C:\boost_1_32_0\boost/serialization/access.hpp" instantiation of "void boost::serialization::access::member_save(Archive &, const T &, const unsigned int) [with Archive=boost::archive::polymorphic_oarchive, T=boost::serialization::binary_object]" at line 42 of "C:\boost_1_32_0\boost/serialization/split_member.hpp" instantiation of "void boost::serialization::detail::member_saver<Archive, T>::invoke(Archive &, const T &, const unsigned int) [with Archive=boost::archive::polymorphic_oarchive, T=boost::serialization::binary_object]" at line 63 of "C:\boost_1_32_0\boost/serialization/split_member.hpp" instantiation of "void boost::serialization::split_member(Archive &, T &, const unsigned int) [with Archive=boost::archive::polymorphic_oarchive, T=boost::serialization::binary_object]" at line 49 instantiation of "void boost::serialization::binary_object::serialize(Archive &, const unsigned int) [with Archive=boost::archive::polymorphic_oarchive]" at line 106 of "C:\boost_1_32_0\boost/serialization/access.hpp" [ 4 instantiation contexts not shown ] instantiation of "void boost::archive::detail::save_non_pointer_type<Archive, T>::invoke(Archive &, const T &) [with Archive=boost::archive::polymorphic_oarchive, T=boost::serialization::binary_object]" at line 551 of "C:\boost_1_32_0\boost/archive/detail/oserializer.hpp" instantiation of "void boost::archive::save(Archive &, const T &) [with Archive=boost::archive::polymorphic_oarchive, T=boost::serialization::binary_object]" at line 106 of "C:\boost_1_32_0\boost/archive/polymorphic_oarchive.hpp" instantiation of "void boost::archive::polymorphic_oarchive::save_override(const T &, int) [with T=boost::serialization::binary_object]" at line 87 of "C:\boost_1_32_0\boost/archive/detail/interface_oarchive.hpp" instantiation of "Archive &boost::archive::detail::interface_oarchive<Archive>::operator&(const T &) [with Archive=boost::archive::polymorphic_oarchive, T=boost::serialization::binary_object]" at line 159 of "C:\boost_1_32_0\boost/archive/detail/polymorphic_oarchive_impl.hpp" instantiation of "boost::archive::polymorphic_oarchive &boost::archive::detail::polymorphic_oarchive_impl<ArchiveImplementation>::operator&(const T &) [with ArchiveImplementation=boost::archive::binary_oarchive_impl<boost::archive::binary_oarchive>, T=boost::serialization::binary_object]" C:\boost_1_32_0\boost/serialization/binary_object.hpp(47): error #308: function "boost::archive::polymorphic_iarchive::load_binary" is inaccessible ar.load_binary(const_cast<void *>(m_t), m_size); ^ detected during: instantiation of "void boost::serialization::binary_object::load(Archive &, const unsigned int) [with Archive=boost::archive::polymorphic_iarchive]" at line 98 of "C:\boost_1_32_0\boost/serialization/access.hpp" instantiation of "void boost::serialization::access::member_load(Archive &, T &, const unsigned int) [with Archive=boost::archive::polymorphic_iarchive, T=boost::serialization::binary_object]" at line 53 of "C:\boost_1_32_0\boost/serialization/split_member.hpp" instantiation of "void boost::serialization::detail::member_loader<Archive, T>::invoke(Archive &, T &, const unsigned int) [with Archive=boost::archive::polymorphic_iarchive, T=boost::serialization::binary_object]" at line 63 of "C:\boost_1_32_0\boost/serialization/split_member.hpp" instantiation of "void boost::serialization::split_member(Archive &, T &, const unsigned int) [with Archive=boost::archive::polymorphic_iarchive, T=boost::serialization::binary_object]" at line 49 instantiation of "void boost::serialization::binary_object::serialize(Archive &, const unsigned int) [with Archive=boost::archive::polymorphic_iarchive]" at line 106 of "C:\boost_1_32_0\boost/serialization/access.hpp" [ 5 instantiation contexts not shown ] instantiation of "void boost::archive::load(Archive &, T &) [with Archive=boost::archive::polymorphic_iarchive, T=boost::serialization::binary_object]" at line 107 of "C:\boost_1_32_0\boost/archive/polymorphic_iarchive.hpp" instantiation of "void boost::archive::polymorphic_iarchive::load_override(T &, int) [with T=boost::serialization::binary_object]" at line 105 of "C:\boost_1_32_0\boost/archive/detail/interface_iarchive.hpp" instantiation of "Archive &boost::archive::detail::interface_iarchive<Archive>::operator>>(const T &) [with Archive=boost::archive::polymorphic_iarchive, T=boost::serialization::binary_object]" at line 111 of "C:\boost_1_32_0\boost/archive/detail/interface_iarchive.hpp" instantiation of "Archive &boost::archive::detail::interface_iarchive<Archive>::operator&(const T &) [with Archive=boost::archive::polymorphic_iarchive, T=boost::serialization::binary_object]" at line 182 of "C:\boost_1_32_0\boost/archive/detail/polymorphic_iarchive_impl.hpp" instantiation of "boost::archive::polymorphic_iarchive &boost::archive::detail::polymorphic_iarchive_impl<ArchiveImplementation>::operator&(const T &) [with ArchiveImplementation=boost::archive::binary_iarchive_impl<boost::archive::binary_iarchive>, T=boost::serialization::binary_object]" compilation aborted for .\TestPolyArchives.cpp (code 2) With best regards, Sergey.

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compile 1_32 on darwin fails for test library (unit_test, prg_exec_monitor, etc)
by John A Meinel 12 Jan '05

12 Jan '05

I'm currently trying to compile all of boost on OS X (10.3.7), using TOOLS=darwin. I already read about the problems with xml_grammar, so I just added: #ifdef NDEBUG template class basic_xml_grammer<char>; #endif //NDEBUG This at least lets the compilation finish. And I'm not using boost::serialization yet. Hopefully Apple will get a fix (I am compiling with their latest build 1671). But I'm running into another problem during the link stage of the test libraries "libboost_unit_test_framework.dylib" It happens in both debug and release builds, I get: ld: Undefined symbols: init_unit_test_suite(int, char**) I found this function defined in auto_unit_test.hpp, and referenced in some of the .cpp files. Now, I'm guessing that this might be intentionally undefined, so that when you bind to the dynamic library, you define your own initialization (probably through a macro), and the library uses that. Has anyone else had this problem? I tried looking through the regression tests, but I haven't found anything that looks like this problem. I saw this post on the mailing list: http://thread.gmane.org/gmane.comp.lib.boost.user/6489 But there were no follow-ups, so I decided to re-post. Is this just a problem with dynamic libraries on Mac, that they can't have undefined symbols? Or is it something else? If it just means that you can only use the static library, that's fine. But why is it compiling the dynamic ones on Mac if they won't succeed? Thanks, John =:->

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Re: size of libboost_thread-gcc-mt.so
by Vladimir Prus 12 Jan '05

12 Jan '05

Alexander Nasonov wrote: > Amerio wrote: >> Hello, >> After compiling libboost_thread-gcc-mt.so on debian/gcc-2.95.4, this so >> weights 195kB, while libpthread weights only 100kB. >> Why such a huge difference ? Isn't boost::thread meant to be as >> lightweight as possible ? > > Try building it with Boost.Build v2 (bjam --v2 gcc release). It's only > 64K because read_write_mutex.o (223K in release) is excluded from link. > I don't know whether it's intentional or an oversight. I'm afraid it's an oversight -- that's a recently added feature. I'm surprised that it adds so much to the size though, let me try here. Without read_write_mutex the size of gcc/release/shared build is 46K. With read_write_mutex the size is 136K. Wow, that's a difference! When I comment out explicit template instantiations in that source file, the library is becomes 76K. The comment says explicit instantination are needed to detect syntax errors in templates but those instantination bloat the library. BTW, I'm not sure read_write_mutex should be a template, either. Maybe, we need class polymorphic_mutex; and template<class Mutex> class concrete_polymorphic_mutex : public polymorphic_mutex { }; and read_write_mutex_impl must be implemented in terms of polymorphic_mutex? - Volodya

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B is_convertible to A<T> for some T
by Agoston Bejo 12 Jan '05

12 Jan '05

Hello, how do I express through template metaprogramming or in a similar way that a class is convertible to a template class for some T1? I.e., the condition: "There exists some T1 such that B is convertible to A<T1>". An example program: (Platform: VC++7.1) --------------------------------------------------- #include <iostream> #include <boost/utility/enable_if.hpp> using namespace std; using namespace boost; template<typename T> struct A {}; struct B : public A<int> {}; template<typename T> struct isA { static const bool value = false; }; template<typename T> struct isA< A<T> > { static const bool value = true; }; // This would give the desired result, but I don't know how it should // legally be expressed it in C++ (if anyhow): //template<typename T, typename TEnabler = void> //struct A { static const bool value = false; }; // //template<typename T, > //struct isA< T, // enable_if<{{T where T is convertible to A<T1> for some T1}}> > //{ // static const bool value = true; //}; int _tmain(int argc, _TCHAR* argv[]) { cout << isA< A<int> >::value << endl; // 1 cout << isA< A<double> >::value << endl;// 1 cout << isA< B >::value << endl; // 0 - not what I want cout << isA<int>::value << endl; // 0 return 0; } ---------------------------------------------------

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Boost Graph Reading and Writing ATT graphviz example compile error
by Welson Sun 12 Jan '05

12 Jan '05

Hi, My platform is Linux (Fedora Core 2), gcc version: gcc (GCC) 3.3.3 20040412 (Red Hat Linux 3.3.3-7) I need to read and write the ATT graphviz format, so this is what I did: 1. Generated the libbgl-viz library. In boost_1_32_0/libs/graph/src/ directory, use the default Makefile, generated the libbgl-viz library without error. And I copied them to /usr/local/lib 2. g++ boost_1_32_0/libs/graph/example/graphviz.cpp, but I got the nasty error: ccVhyZaG.o(.text+0x602):graphviz.cpp: undefined reference to `boost::read_graphviz(std::basic_string<char, std::char_t raits<char>, std::allocator<char> > const&, boost::subgraph<boost::adjacency_lis t<boost::vecS, boost::vecS, boost::directedS, boost::property<boost::vertex_attr ibute_t, std::map<std::basic_string<char, std::char_traits<char>, std::allocator <char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > , std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, s td::allocator<char> > const, std::basic_string<char, std::char_traits<char>, std ::allocator<char> > > > >, boost::no_property>, boost::property<boost::edge_attr ibute_t, std::map<std::basic_string<char, std::char_traits<char>, std::allocator <char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > , std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, s td::allocator<char> > const, std::basic_string<char, std::char_traits<char>, std ::allocator<char> > > > >, boost::property<boost::edge_index_t, int, boost::no_p roperty> >, boost::property<boost::graph_graph_attribute_t, std::map<std::basic_ string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<c har, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string <char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pai r<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, bo ost::property<boost::graph_vertex_attribute_t, std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::cha r_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::c har_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_ string<char, std::char_traits<char>, std::allocator<char> > const, std::basic_st ring<char, std::char_traits<char>, std::allocator<char> > > > >, boost::property <boost::graph_edge_attribute_t, std::map<std::basic_string<char, std::char_trait s<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char >, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, st d::char_traits<char>, std::allocator<char> > const, std::basic_string<char, std: :char_traits<char>, std::allocator<char> > > > >, boost::property<boost::graph_n ame_t, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, b oost::no_property> > > >, boost::listS> >&)' collect2: ld returned 1 exit status What's the matter?

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bug in mersenne twister
by Morgan 11 Jan '05

11 Jan '05

This is my first bug report(ever), so feel free to point out how I could do a better job of this... Anyways I have found a bug with the mersenne_twister random number generator class, where results when calling for a random number vary between codewarrior 9.0 and gcc 3.4.1 with boost 1.31.0. A simple example is shown below: #include <boost/random/mersenne_twister.hpp> // for mt11213b typedef boost::mt11213b base_generator_type; class foo { public: foo(const base_generator_type gen):m_gen(gen) {} ~foo(void) {} rand_type operator() ( void ) { const float x = m_gen(); return x; } private: base_generator_type m_gen; } int main(void) { base_generator_type gen( (uint32_t) 2000); seed is not important foo f(gen); cout << "Random result is " << f() << endl; } The resulting numbers will be different between codewarrior 9.0 running on windows and gcc 3.4.1 running on Suse linux 7.3.(Hope that is enough info). I tracked the cause of the bug down to class initialization. In the case of CW9.0, the compiler when constructing a foo, will use a mersenne_twister copy ctor when initializing m_gen, while in the case of gcc 3.4.1 it will choose the following in the .hpp file template<class Generator> explicit mersenne_twister(Generator & gen) { seed(gen); } therefore using the provided generator as a seed to the new generator rather than just copying its state, even though no template parameter is provided. Anyways I will leave it up to the more informed to decide which is more desirable/proper; however, this is a fairly nasty bug at the moment as

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How can I uninstall Boost with bjam?
by Welson Sun 11 Jan '05

11 Jan '05

I tried "bjam uninstall", but doesn't work. I searched the web and maillist, looks like no one has ever talked about it. Yours, Welson Sun

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Serialization and shared_ptr
by Jarl Lindrud 11 Jan '05

11 Jan '05

Hi! A question on serializing pointers to derived classes: When I serialize naked polymorphic pointers through base pointers, things work as expected, ie the derived classes are serailized and deserialized. However, when I replace the naked pointers with corresponding boost::shared_ptr's, I get an archive_exception, to the tune of "unregistered class". I'm using BOOST_CLASS_EXPORT, and not the register_type<> functions. Is this supposed to happen, or do I need some additional type registration beyond what was necessary for serializing naked pointers? Thanks! Jarl. The code: //B and C derive from A std::ostringstream os; boost::archive::text_oarchive oa(os); //A *pb0 = new B(15,16); //A *pc0 = new C(17, 18, 19); boost::shared_ptr<A> pb0( new B(15,16) ); boost::shared_ptr<A> pc0( new C(17, 18, 19) ); oa << pb0; oa << pc0; std::string data = os.str(); { std::istringstream is(data); boost::archive::text_iarchive ia(is); //A *pa1 = NULL; //A *pa2 = NULL; boost::shared_ptr<A> pa1; boost::shared_ptr<A> pa2; ia >> pa1; ia >> pa2; B* pb = dynamic_cast<B *>(pa1.get()); C* pc = dynamic_cast<C *>(pa2.get()); } _________________________________________________________________ Express yourself instantly with MSN Messenger! Download today it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/

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Forwarding problem in base_from_member
by Jens Theisen 11 Jan '05

11 Jan '05

Hello, the above class (doesn't?) currently addresses the forwarding problem by passing constructor argument by value. Would it not be a better idea to use const&? We can't pass variable references at the moment, can we? Cheers, Jens

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RE: [Boost-users] Re: C++ Template Metaprogramming - Exercise 2-0
by Trask, Bruce (US SSA) 11 Jan '05

11 Jan '05

Philippe, > Given that, it is trivial to modify Eric's solution to have the > proper result. > Right. As they say in New England, Dawn in beginning to break over Marblehead. It took me four cracks to get it, but I think I got it now (see below and tell me if I do). (thanks for not telling me the answer outright) I starting to get the hang of it. Exercise 2.0 down. That's one in a row :) #include <iostream> #include <boost/type_traits/is_reference.hpp> #include <boost/type_traits/add_reference.hpp> #include <boost/type_traits/add_const.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/static_assert.hpp> using namespace std; template<typename T> struct add_const_ref { typedef typename boost::add_reference<typename boost::add_const<T>::type>::type type; }; int main() { BOOST_STATIC_ASSERT((boost::is_same<boost::add_const<int>::type, const int>::value)); BOOST_STATIC_ASSERT((boost::is_same<boost::add_reference<int>::type, int&>::value)); BOOST_STATIC_ASSERT((boost::is_same<boost::add_const<int&>::type, int&>::value)); BOOST_STATIC_ASSERT((boost::is_same<boost::add_reference<boost::add_cons t<int>::type>::type, int const&>::value)); BOOST_STATIC_ASSERT((boost::is_same<add_const_ref<int&>::type, int&>::value)); BOOST_STATIC_ASSERT((boost::is_same<add_const_ref<int>::type, int const&>::value)); return 0; } Thanks for the input, Bruce > Philippe > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Re: C++ Template Metaprogramming - Exercise 2-0
by Lemings, Eric B. (Contr) 11 Jan '05

11 Jan '05

Dave Abrahams wrote: > Actually there's a much more concise solution using the type traits > library. That is, after all, the focus of the chapter. I believe that would be: template <typename T> struct add_const_ref { typedef add_const<add_ref<T>::type>::type type; }; Correct me if I'm wrong. Eric.

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Re: C++ Template Metaprogramming - Exercise 2-0
by Lemings, Eric B. (Contr) 11 Jan '05

11 Jan '05

Dave Abrahams wrote: > Actually there's a much more concise solution using the type traits > library. That is, after all, the focus of the chapter. I believe that would be: template <typename T> struct add_const_ref { typedef add_const<add_ref<T>::type>::type type; }; Correct me if I'm wrong. Eric.

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Zero/Null Metafunction?
by Lemings, Eric B. (Contr) 10 Jan '05

10 Jan '05

Hi, I was wondering if there is a zero/null value metafunction in the Boost libraries? Something like the following: null<int>::value // 0 null<float>::value // 0.0 null<void*>::value // 0 or NULL null<int&>::value // undefined Thanks, Eric.

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Re: [sigc] Re: [Boost-users] Signals & Slots
by Doug Gregor 10 Jan '05

10 Jan '05

On Jan 9, 2005, at 11:35 AM, Martin Schulze wrote: > Am 07.01.2005 14:19:20 schrieb(en) Douglas Gregor: >> If I'm right in assuming that the code will not compile (because the >> signatures do not match exactly), then the "No Clue" could be replaced >> by "Not Applicable", because >> Signals performs all of the implicit conversions. > > I'm afraid, you're wrong here. Implicit conversions do work. > retype(_return) is for explicit conversions. > However, using implicit conversions in libsigc++-2.0 without > retype(_return) can cause troubles (at least warnings) with some > compilers. Okay, good. Then I don't have to try to motivate the need for implicit conversions :) >> - About ptr_fun/mem_fun: you can use them in either library, if >> you'd >> like to be more explicit. >> - About bind: bind is now in the C++ Library TR (an addendum to the >> standard, which should be approved in the near future), so we're >> forced >> to build on it to create any signals & slots library for the standards >> committee. (We'll have a long, uphill battle if we try to introduce >> our >> own special binders and don't support bind). > > Is there a way to deduce the return type of the bind functor object > that is part of the TR? Yes. It's called "result_of" in the Library TR. > Will it be possible to "visit the targets" that are stored in the > bind functor object with a function like Boost::visit_each() or > sigc::visit_each()? This functionality was not included because it was not necessary for anything in the Library TR (and would otherwise be hard to motivate). We could propose this as part of a signals 'n' slots system, of course. >> - Regarding libsigc++'s specialization for T_accumulator=nil: We >> don't need to discuss this in a standards proposal, because it's >> entirely a quality-of-implementation issue. >> - Regarding Signals and Function: They don't play well together, >> but >> we're going to have to deal with this one way or another because >> Function is also part of the C++ Library TR. > > I always thought that Boost had quite some influence on standard > proposal? Who come that the TR is in a bad shape for a signal system, > then? I wouldn't say that it is in bad shape for a signal system. The problem with {boost:: or tr1::}function and a signals system is that they both do the same thing: erase the static type of a function object so that it can be called through an entity that does not encode that type. The problem is that we need to call visit_each before we erase that type: 'function' shouldn't do it all the time, because that could be costly, and the signal/slot can't do it because the type is gone. We can probably come up with a not-too-painful solution, if we're clever enough. Doug

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