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RE: [Boost-Users] simplest pool_alloc example does not work on VC 6
by scleary＠jerviswebb.com 23 Apr '03

23 Apr '03

John - Sorry, Boost.Pool does not currently support MSVC, due to that compiler's extreme lack of template support. -Steve > -----Original Message----- > From: John Harris [mailto:john.harris@tradingtechnologies.com] > > Using Boost 1.30.0. MSVC6 > Tow problems: (1) I have to #define __WIN32__, and (2) Doesn't compile

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The unholy triumvirate of Boost, MacOS X & gcc
by Paul-Michael Agapow 23 Apr '03

23 Apr '03

Does any one have recent experience with compiling / installing Boost on a Mac using gcc? A brief vox-poll seems to say that most everyone on the Mac uses it with CodeWarrior, manually including it in their project. However I'm more interested in using gcc / ProjectBuilder, and distributing the source code to my programs. So, I need to know if my end-users are going to have any problems installing Boost? My attempts have been been discouraging. The first install of Spirit almost immediately consumed all the memory on my machine and thrashed. Installation of the full Boost failed with link errors reporting "unrecognised option shared". Editing this option out of the regex makefile, lead to the next problem, failures with the unittests. Suspecting I was missing something obvious, I handed the problem over to someone else who spend a few days following the same trail, eventually commenting out the unittests. Sure, I could include the boost source with every program I use it in, but this strikes me as untidy and means every time Boost updates, I have to update the x separate copies on my disk. Opinions or sympathies? p -- Dr Paul-Michael Agapow (p.agapow(a)ucl.ac.uk) Dept. Biology, University College London

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Using for_each on a std::list<boost::function0<void> >
by Russell Hind 23 Apr '03

23 Apr '03

I have a std::list of boost::function0<void> I would like to call all items using a for_each statement. Is there a standard function object that I can pass into the for_each call that will call operator() on each element? Thanks Russell

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dijkstra_shortest_paths with undirectedS example
by jfw1000 23 Apr '03

23 Apr '03

Hello, I am new to BGL, I was trying to test dijkstra_shortest_paths() with undirectedS, the result is not what I wanted, anyone giving help? Thanks, source code like dijkstra-example.cpp in the graph/example. int main(int, char *[]) { typedef adjacency_list < listS, vecS, undirectedS, no_property, property < edge_weight_t, double > > graph_t; typedef graph_traits < graph_t >::vertex_descriptor vertex_descriptor; typedef graph_traits < graph_t >::edge_descriptor edge_descriptor; typedef std::pair<int, int> Edge; const int num_nodes = 3; Edge edge_array[] = { Edge(0, 1),Edge(1, 2), Edge(2, 0) }; double weights[] = {2.0, 1.0, 1.0}; int num_arcs = sizeof(edge_array) / sizeof(Edge);// #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300 graph_t g(num_nodes); property_map<graph_t, edge_weight_t>::type weightmap = get (edge_weight, g); for (std::size_t j = 0; j < num_arcs; ++j) { edge_descriptor e; bool inserted; tie(e, inserted) = add_edge(edge_array[j].first, edge_array [j].second, g); weightmap[e] = weights[j]; } #else graph_t g(edge_array, edge_array + num_arcs, weights, num_nodes); property_map<graph_t, edge_weight_t>::type weightmap = get (edge_weight, g); #endif std::vector<vertex_descriptor> pred(num_vertices(g)); std::vector<double> d(num_vertices(g)); vertex_descriptor s = vertex(0, g); #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300 // VC++ has trouble with the named parameters mechanism property_map<graph_t, vertex_index_t>::type indexmap = get (vertex_index, g); dijkstra_shortest_paths(g, s, &pred[0], &d[0], weightmap, indexmap, std::less<double>(), closed_plus<double>(), std::numeric_limits<double>::max(), 0, default_dijkstra_visitor()); #else dijkstra_shortest_paths(g, s, predecessor_map(&p[0]).distance_map(&d [0])); #endif std::cout << "distances and parents:" << std::endl; graph_traits < graph_t >::vertex_iterator vi, vend; for (tie(vi, vend) = vertices(g); vi != vend; ++vi) { std::cout << "distance(" << *vi << ") = " << d[*vi] << ", "; std::cout << "parent(" << *vi << ") = " << pred[*vi] << std::endl; } std::cout << "min paths tree" << std::endl; adjacency_list<> tree(num_nodes); for(tie(vi,vend) = vertices(g); vi != vend; ++vi) if (*vi != pred[*vi]) add_edge(pred[*vi], *vi, tree); print_graph(tree); std::cout << std::endl; return EXIT_SUCCESS; } The result is : distances and parents: distance(0) = 0, parent(0) = 0 distance(1) = 2, parent(1) = 0 distance(0) = 1, parent(2) = 0 min paths tree 0 -> 1 2 1 -> 2 -> I think the correct one should be: distances and parents: distance(0) = 0, parent(0) = 0 distance(1) = 2, parent(1) = 2 distance(2) = 1, parent(2) = 0 min paths tree 0 -> 1 1 -> 2 2 -> Any idea what is wrong? thanks!

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RE: [Boost-Users] simplest pool_alloc example does not work on VC 6
by scleary＠jerviswebb.com 23 Apr '03

23 Apr '03

> -----Original Message----- > From: Ben Hutchings [mailto:ben.hutchings@businesswebsoftware.com] > > scleary(a)jerviswebb.com wrote: > > Sorry, Boost.Pool does not currently support MSVC, due to that > compiler's > > extreme lack of template support. > <snip> > > For VC++ 6, all that should be needed is a _Charalloc function (instead > of struct rebind) and a change to the type of deallocate's first > parameter (to void *, which actually makes more sense). The _Charalloc function requires each allocator to be able to allocate an arbitrary amount of memory. This goes against the entire design of Boost.Pool, and would be non-trivial (to say the least) to implement. > The VC++ 7 compiler is good enough to support standard allocators and > the library does use them. With the addition of a variable name and > semi-colon, the given example can be compiled with this version. Glad to hear it. Too bad it's not released yet. -Steve

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RE: [Boost-Users] Boost::Filesystem: Directory iterator and dangling links
by Ben Hutchings 23 Apr '03

23 Apr '03

You wrote: <snip> > In the case of dangling links I obtain a not_found_error. > This seems to be a contradiction. First I find something (and obtain an > iterator) and without any interference from > outside is_directory() tells me it cannot find the object. > The problem is that directory_iterator refers to the link whereas > is_directory() and the following exception refer to the target (which is > missing). <snip> To make this consistent, then, maybe is_directory() and friends should be using lstat rather than stat on Unix. Is it desirable that links be resolved? I suppose it is if the iterator is being used to walk a whole tree - but not if it's being used to list a single directory. Perhaps there is a need to include explicit support for links in the API. Windows has supported them since 2000, so they aren't just a Unix thing now.

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RE: [Boost-Users] simplest pool_alloc example does not work on VC 6
by Beman Dawes 22 Apr '03

22 Apr '03

At 01:40 PM 4/22/2003, scleary(a)jerviswebb.com wrote: >> -----Original Message----- >> From: Ben Hutchings [mailto:ben.hutchings@businesswebsoftware.com] >>... >> The VC++ 7 compiler is good enough to support standard allocators and >> the library does use them. With the addition of a variable name and >> semi-colon, the given example can be compiled with this version. > >Glad to hear it. Too bad it's not released yet. Ben is probably talking about 7.0, which has been released for a year or so. VC++ 7.1 will be released officially Thursday, the 24th, IIRC. Using the VC++ 7.1 final beta, test_pool_alloc is passing OK. --Beman

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RE: [Boost-Users] simplest pool_alloc example does not work on VC6
by Ben Hutchings 22 Apr '03

22 Apr '03

scleary(a)jerviswebb.com wrote: > Ben Hutchings <ben.hutchings(a)businesswebsoftware.com> wrote: > > scleary(a)jerviswebb.com wrote: > > > Sorry, Boost.Pool does not currently support MSVC, due to that compiler's > > > extreme lack of template support. <snip> > > The VC++ 7 compiler is good enough to support standard allocators and > > the library does use them. With the addition of a variable name and > > semi-colon, the given example can be compiled with this version. > > Glad to hear it. Too bad it's not released yet. Where have you been for the last year?

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Newbie boost help needed..
by Bryan Coon 22 Apr '03

22 Apr '03

Hi, I am totally new to boost and just wanted to ask a couple of simple questions... First, I compiled the boost libraries okay with msvc. I updated the include path in my vc++ 6.0, and can include boost files via #include <boost/xxx.hpp>. So far so good! I wanted to try some things out, like boost's mersenne twister random number generator. I first did this: #include <boost/random/mersenn_twister.hpp> And got no errors. Then I read there was a random.hpp for convenience so I changed this to: #include <boost/random.hpp> And received as a reward complaints: d:\dev\devproject\boost_1_30_0\boost\random\uniform_01.hpp(44) : error C2275: 'std::numeric_limits<`template-parameter258'>::is_integer' : illegal use of this type as an expression d:\dev\devproject\boost_1_30_0\boost\random\uniform_01.hpp(95) : see reference to class template instantiation 'boost::uniform_01<UniformRandomNumberGenerator,RealType>' being compiled There were 6 of these errors. What am I doing wrong? Also, is there a way to include the boost libs in vc++ where I get the autocompletion if I use boost:: ? It is very difficult to figure out how the libs are supposed to be used (for me) by looking at example code or the documentation. Autocompletion as if boost were part of my project would be very useful. Thanks, B

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RE: [Boost-Users] simplest pool_alloc example does not work on VC6
by Ben Hutchings 22 Apr '03

22 Apr '03

scleary(a)jerviswebb.com wrote: > Sorry, Boost.Pool does not currently support MSVC, due to that compiler's > extreme lack of template support. <snip> For VC++ 6, all that should be needed is a _Charalloc function (instead of struct rebind) and a change to the type of deallocate's first parameter (to void *, which actually makes more sense). The VC++ 7 compiler is good enough to support standard allocators and the library does use them. With the addition of a variable name and semi-colon, the given example can be compiled with this version. Is there some other reason why VC++ cannot be supported?

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simplest pool_alloc example does not work on VC6
by John Harris 22 Apr '03

22 Apr '03

Using Boost 1.30.0. MSVC6 Tow problems: (1) I have to #define __WIN32__, and (2) Doesn't compile Am I doing something wrong, here? #include "afxwin.h" #include <map> #define __WIN32__ // why do I have to define this??? #include "boost/pool/pool_alloc.hpp" int main() { std::map<int,int,std::less<int>, boost::pool_allocator<int> > return 0; } :\Program Files\Microsoft Visual Studio\VC98\INCLUDE\xtree(587) : error C2664: 'deallocate' : cannot convert parameter 1 from 'struct std::_Tree<int,struct std::pair<int const ,int>,struct std::map<int,int,struct std::less<int>,class boost::pool_al locator<int,struct boost::default_user_allocator_new_delete,class boost::details::pool::win32_mutex,32> >::_Kfn,struct std::less<int>,class boost::pool_allocator<int,struct boost::default_user_allocator_new_delete,class boost::details::pool::win32_m utex,32> >::_Node *' to 'int *const ' Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast C:\Program Files\Microsoft Visual Studio\VC98\INCLUDE\xtree (587) : while compiling class-template member function 'void __thiscall std::_Tree<int,struct std::pair<int const ,int>,struct std::map<int,int,struct std::less<int>,class boost::poo l_allocator<int,struct boost::default_user_allocator_new_delete,class boost::details::pool::win32_mutex,32> >::_Kfn,struct std::less<int>,class boost::pool_allocator<int,struct boost::default_user_allocator_new_delete,class boost::details::pool::win 32_mutex,32> >::_Freenode(struct std::_Tree<int,struct std::pair<int const ,int>,struct std::map<int,int,struct std::less<int>,class boost::pool_allocator<int,struct boost::default_user_allocator_new_delete,class boost::details::pool::win32_mutex,32 > >::_Kfn,struct std::less<int>,class boost::pool_allocator<int,struct boost::default_user_allocator_new_delete,class boost::details::pool::win32_mutex,32> >::_Node *)'

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boost::thread warnings?
by olexander_shyrokov 21 Apr '03

21 Apr '03

I got some warnings when compiling my program (see below). I am using Visual Studio C++ 6 and STLport 4.5.3 I've seen some questions about this issue in the mailing list, but did not get the feeling that I understand what is going on and when I can safly ignore them? Thanks a lot. c:\src\boost\boost\thread\exceptions.hpp(29) : warning C4275: non dll-interface class '_STL::logic_error' used as base for dll-interface class 'boost::lock_error' c:\progra~1\micros~3\vc98\include\stlport\stdexcept(72) : see declaration of 'logic_error' c:\src\boost\boost\thread\exceptions.hpp(35) : warning C4275: non dll-interface class '_STL::runtime_error' used as base for dll-interface class 'boost::thread_resource_error' c:\progra~1\micros~3\vc98\include\stlport\stdexcept(80) : see declaration of 'runtime_error' c:\src\boost\boost\thread\mutex.hpp(37) : warning C4275: non dll-interface class 'boost::noncopyable' used as base for dll-interface class 'boost::mutex' c:\src\boost\boost\noncopyable.hpp(22) : see declaration of 'noncopyable' c:\src\boost\boost\thread\mutex.hpp(75) : warning C4275: non dll-interface class 'boost::noncopyable' used as base for dll-interface class 'boost::try_mutex' c:\src\boost\boost\noncopyable.hpp(22) : see declaration of 'noncopyable' c:\src\boost\boost\thread\mutex.hpp(115) : warning C4275: non dll-interface class 'boost::noncopyable' used as base for dll-interface class 'boost::timed_mutex' c:\src\boost\boost\noncopyable.hpp(22) : see declaration of 'noncopyable' c:\src\boost\boost\thread\thread.hpp(39) : warning C4275: non dll-interface class 'boost::noncopyable' used as base for dll-interface class 'boost::thread' c:\src\boost\boost\noncopyable.hpp(22) : see declaration of 'noncopyable' c:\src\boost\boost\thread\thread.hpp(68) : warning C4275: non dll-interface class 'boost::noncopyable' used as base for dll-interface class 'boost::thread_group' c:\src\boost\boost\noncopyable.hpp(22) : see declaration of 'noncopyable' c:\src\boost\boost\thread\thread.hpp(79) : warning C4251: 'm_threads' : class '_STL::list<class boost::thread *,class _STL::allocator<class boost::thread *> >' needs to have dll-interface to be used by clients of class 'boost::thread_group'

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Problems linking with Boost 1.29.0 thread lib, Linux/g++ 3.2.2 -r2
by subsample 21 Apr '03

21 Apr '03

Failing to link a program with libboost_thread, even though I supply the -lboost_thread directive in the makefile. I'm kind of new to makefiles, having only used Visual C++ in Windows untill recently. I 've tried changing things around a bit, doesn't help. A minimal test program I wrote links fine with boost_thread though. My makefile looks like this: CC=g++ CFLAGS=-g LDFLAGS=-L/home/sub/Libs/alsa/lib -lasound -lboost_thread -lpthread alsatest: alsatest.o $(CC) $(LDFLAGS) -o alsatest SmallObj.o alsatest.o alsatest.o: smallobj.o $(CC) $(CFLAGS) alsatest.cpp -c smallobj.o: $(CC) $(CFLAGS) /usr/include/loki/SmallObj.cpp -c clean: rm -f *.o alsatest g++ complains about the same missing references no matter if I include the -lboost_thread or not. If someone could point out what I'm doing wrong I'd be grateful : )

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Typo in boost/config/compiler/visualc.hpp
by Vaclav Vesely 19 Apr '03

19 Apr '03

line 26: #if (_MSC_VER <= 1300) // 1200 == VC++ 7.0 The comment is inconsistent with the code. Regards, w

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RE: [Boost-Users] lexical_cast regression
by Tom Matelich 18 Apr '03

18 Apr '03

> From: Terje Slettebø [mailto:tslettebo@chello.no] > > >From: "Tom Matelich" <tmatelich(a)zetec.com> > > > I haven't gone and looked at the boost ml archives to track > > the reason for > > this down, but the addition of stream.unsetf(std::ios::skipws) in > > lexical_cast caused some of our code to fail. I've commented it out > > locally, and was wondering why it was decided this is more > > appropriate default behavior. > > It was done to avoid the problems with throwing exceptions on > whitespace. > For example, without it, the following would throw a bad_lexical_cast: > > lexical_cast<std::string>(' '); // A space character > > What kind of code is the current version failing at? > We have some legacy files that are converted to xml through some process (I didn't write it) and it ends up with space-padded strings for ints. So the test case was dying converting " 86" to an int. I can see its purpose, except that example wouldn't happen because of the std::string overload, right? Tom ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------

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Re: [boost] lexical_cast problem
by Terje Slettebø 18 Apr '03

18 Apr '03

>From: "Terje Slettebø" <tslettebo(a)chello.no> > Hm, just now, I sent a reply to a similar problem report at Boost-Users > list, about why whitespace skipping is turned off in the new lexical_cast > version. It was to avoid having things like "lexical_cast<std::string>(' '); > // Space character" work, which used to throw an exception. I meant it was to avoid having it throw an exception, in other words, to _have_ it work. Terje

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Re: [boost] lexical_cast problem
by Terje Slettebø 18 Apr '03

18 Apr '03

>From: "Vladimir Prus" <ghost(a)cs.msu.su> >Subject: [boost] lexical_cast problem Not again. :) > I've just updated my project to use boost 1.30 and also gcc 3.2 and see > exception which reads: > > bad lexical cast: source type value could not be interpreted as target, > Target=i, Source=Ss Ah, yes, good ol' g++ with its wonderfully descriptive type_info names... ;) > The simple reproduction recipe is: > > #include <boost/lexical_cast.hpp> > #include <string> > > int main() > { > boost::lexical_cast<int>(std::string(" 0")); > } "Houston, we have a problem..." Hm, just now, I sent a reply to a similar problem report at Boost-Users list, about why whitespace skipping is turned off in the new lexical_cast version. It was to avoid having things like "lexical_cast<std::string>(' '); // Space character" work, which used to throw an exception. However, it seems this change has had undesired side-effects, in that code like the above now fails to work. Frankly, I don't know what to do with this... > Note the space in string. The exception does not occur with gcc 2.95, but only > with 3.2. I wonder if this should/can be fixed? Personally, I'd expect this > code to work. > > And a related note: the exception's what() above is not quite helpfull. The current version in the CVS has got a changed exception handling, where bad_lexical_cast now looks like this: class bad_lexical_cast : public std::bad_cast { public: // ... const std::type_info &source_type() const const std::type_info &target_type() const virtual const char *what() const throw() { return "bad lexical cast: " "source type value could not be interpreted as target"; } }; In other words, what() now returns the original text, and the type_info objects for the types used is now returned by member functions. > Is it > possible to output the stringstream content (if source -> stringstream > conversion was successfull?) Yes, that's possible. I guess I'll leave it to Kevlin to comment on this. Thanks for the report, to both you and Tom Matelich at Boost-Users list. Regards, Terje

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lexical_cast regression
by Tom Matelich 18 Apr '03

18 Apr '03

I haven't gone and looked at the boost ml archives to track the reason for this down, but the addition of stream.unsetf(std::ios::skipws) in lexical_cast caused some of our code to fail. I've commented it out locally, and was wondering why it was decided this is more appropriate default behavior. Thanks, Tom ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------

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kinda, sorta, like an iterator for dynamic_bitset, but not really.
by Andy Klapper 18 Apr '03

18 Apr '03

I'm currently writing some code for a client where I make extensive use of dynamic_bitsets to determine very quickly which options are appropriate based on a number of criteria. I set up before hand dynamic_bitset for each person, place, and thing which are then bitwise AND'd together to determine where the points of intersection are. What I need is something with an iterator syntax that returns the indexes whose values are set. I could of course just loop through looking for set values, but that seems silly when you think that entire blocks of bits can be skipped if the block has a value of zero. So my questions is, before I set out to write some code, has somebody already done this? It seems like a logical use of dynamic_bit set so it does not seem implausible. If not, any suggestions or warnings? Thanks, Andy

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Understanding MPL
by Edward Diener 18 Apr '03

18 Apr '03

I am trying to understand how the MPL library works. I first read "The Boost C++ Metaprogramming Library" by Aleksey Gurtovoy and David Abrahams. When I get to Basic Usage I see this: template< typename Condition , typename T1 , typename T2 > struct if_ { typedef /*unspecified*/ type; }; I am really having trouble understanding the next to last line. How can "typedef type;" be a valid C++ construct and, if it is, what does it mean ? I always though that a typedef must specify an actual type but I don't see any in the expression above.

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RE: [Boost-Users] Re: command line parsing
by Ben Hutchings 17 Apr '03

17 Apr '03

E. Scott Larsen wrote: > Just FYI to this thread in general. It's been a while since I've messed > with WinMain and command lines, but if my memory serves me right (it was > at a different place, so I don't have the code here), there's some > additional whacky issues here. WinMain recieves the first arguments > differently depending on how it is run: > *) from MSVC debugger > *) from a commandline > *) by clicking on an shortcut icon > *) by clicking in an explorer window I find this hard to believe, as WinMain is just given a pointer into the command line returned by GetCommandLine(), incremented past the program name and any following space. > don't remember which is which, but one gives just the executable name, > one gives the full path to the executable (seems like there's two > variations on this, like one is quoted and one is not, don't remember > the details), and it seems like there's one that doesn't give the > executable at all. I can imagine there's some variation in program name; it's normal for programs to be started with short names rather than their full filenames. The quoting is weird though; that should be removed before you see it. > Also, I _distinctly_ remember something very whacky when I used unicode, > I don't remember the details, but the commandline arguments were a > significant pain for a program built with unicode support using the > unicode windows entry function. That still tastes bad in my mouth. According to the docs, this ought to work: wchar_t ** argv; int argc; argv = CommandLineToArgvW(GetCommandLineW(), &argc); but I've never tried it; maybe it doesn't. If you were using WinCE then I feel your pain and hope you've recovered.

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RE: [Boost-Users] Powers
by Jim.Hyslop 17 Apr '03

17 Apr '03

basicxml2011 [mailto:basicxml2011@yahoo.com] wrote: > Is their any library or function that can raise a number to a power? Do you mean besides the standard pow() function? -- Jim

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mpl::is_same<Class<A>, T> ?
by Markus Werle 17 Apr '03

17 Apr '03

Hi! Is there a convenient way inside boost::mpl to check whether a certain type T is a template Class<A> with A unspecified? Markus -- Compile time analytic differentiation? Yes, at http://daixtrose.sourceforge.net/

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How to build regex on an Alpha-Dec (True64)?
by Ralf Hupfer 17 Apr '03

17 Apr '03

Hi All, I am having trouble with regex on an Alpha-Dec with Compaq's compiler 6.3. I've got regex to compile with generic.mak as follows: CXX="cxx" CXXFLAGS="-inline-none" -D__USE_STD_IOSTREAM -DBOOST_REGEX_NO_EXTERNAL_TEMPLATES" LINKER="cxx" gnumake generic.mak but then it comes to the link step an error occures: ld: Unresolved: main Nevertheless, boost_regex.so is being build, but when I try to link an application with boost_regex.so I do get loads of errors concerning the C++ standard library: ld (prelink): /usr/lib/cmplrs/cxx/V6.3-008/libcxxstd.a(cxxl_std_init.o): std::cout: multiply defined Warning: std::basic_string<char, std::char_traits<char>, std::allocator<char> >::npos defined as GLOBAL RCONST but is defined in a shared lib as a GLOBAL OBJECT Warning: std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >::npos defined as GLOBAL RCONST but is defined in a shared lib as a GLOBAL OBJECT Warning: std::locale::collate defined as GLOBAL RCONST but is defined in a shared lib as a GLOBAL OBJECT Warning: std::locale::ctype defined as GLOBAL RCONST but is defined in a shared lib as a GLOBAL OBJECT Warning: std::locale::monetary defined as GLOBAL RCONST but is defined in a shared lib as a GLOBAL OBJECT Warning: std::locale::numeric defined as GLOBAL RCONST but is defined in a shared lib as a GLOBAL OBJECT ... Does anybody know what's wrong there? Both -D__USE_STD_IOSTREAM and -DBOOST_REGEX_NO_EXTERNAL_TEMPLATES are necessary to compile regex at all. -D__USE_STD_IOSTREAM tells the compiler to use the standard iostream library instead of the older non-standard version (which is the default for this platform). Without -DBOOST_REGEX_NO_EXTERNAL_TEMPLATES the compiler complains about some templates. I also tried to compile regex with gcc, but again I could not link the application. Linking gcc-compiled (c++) libraries with Compaq's object files and vice versa does not seem to work in generall. Building everything with gcc failed due to seome other incompatibilities. Thanks for any help. Ralf

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RE: [Boost-Users] Re: command line parsing
by Ben Hutchings 17 Apr '03

17 Apr '03

I wrote: > That is correct. Windows programs receive given a single string of > arguments to parse whereas Unix programs receive a vector which can > be passed to main unchanged by the startup code. ... > A full solution will need to be a little bit more complicated. There > isn't a specification of how Windows command-lines should be generated > or interpreted from an array of strings... What I should have written is: Windows programs receive a single string of arguments to parse whereas Unix programs receive an array which can be passed to main unchanged by the startup code. ... A full solution will need to be a little bit more complicated. There isn't a specification of how Windows command-lines should be converted to or from an array of strings... By the way, the startup code or other command-line parser does not have to handle redirection or variable substitution; this *is* done by the command processor (which implies that it does parse the command- line, even though it doesn't give you the results of this).

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It's there a pitfall in boost::regex?
by Phipps Xue 17 Apr '03

17 Apr '03

Good morning all, I used regex library which is shipped with boost 1.30 in my project. But I found in the case I list below, the regex_match() will crash. Is there a pitfall in it? ===================== CODE LIST BEGIN ========================= #include "stdafx.h" #include <afxconv.h> #include <boost/regex.hpp> using namespace boost; void do_regex_match(const string& s) { USES_CONVERSION; CString _c1,_c2; _c1 = "\\_gl_glcf]a:(D_N~yOA_gg_aeN_o/>jm_gf'0(m_--\\6L_gi_AE_gd5<&0A~_E'_Y-'-,uO7_so_glTc G_gl_C,_o/*6hC=@_u"; // Failed _c2 = "\\_gl_glcf]a:(D_N~yOA_gg_aeN_o/jm_gf'0(m_--\\6L_gi_AE_gd5<&0A~_E'_Y-'-,uO7_so_glTc G_gl_C,_o/*6hC=@_u"; // Passed wstring ws1(L""),ws2(L""); ws1=A2W(_c1); ws2=A2W(_c2); wstring wsMatchString(L""); wsMatchString=A2W(".*(要)?.*天气.*"); boost::wregex e(wsMatchString/*,boost::regbase::normal|boost::regbase::icase*/); boost::regex_match(ws2,e);// Pass boost::regex_match(ws1,e);// Crash } ======================== CODE LIST END ========================= As you can see in the code, if any change is made to _c1, the test will pass or it will crash. I will list my compiler and system information below. Compiler: Microsoft Visual C++ 6.0 Professionall with SP5 OS: Microsoft Windows 2000 Professional with SP3 RAM: 512M CPU: PIII 700 Any help will be appreciated. Phipps Xue Software Engineer, MCP/MCSD Email: xuejm(a)sina.com

2 1

Powers
by basicxml2011 17 Apr '03

17 Apr '03

Is their any library or function that can raise a number to a power?

1 0

RE: [Boost-Users] Re: command line parsing
by Ben Hutchings 17 Apr '03

17 Apr '03

Vladimir Prus wrote: > cl_corba_at wrote: <snip> > >> Frankly, I've missed the WinMain case, and not sure what to do. > >> The problem is that single string might erase important > >> information --- what happens if you have command line argument > >> with embedded space. > > > > Embedded spaces should be placed in quotation marks which should be > > removed by the tokenizer. Arguments could be seperated by one ore more > > space. > > Do you mean that if I type > > program "a b c" "C:/Program files" > > then the program will receive this string, with quotes there? > (The linux shell will strip quotes completely). That is correct. Windows programs receive given a single string of arguments to parse whereas Unix programs receive a vector which can be passed to main unchanged by the startup code. <snip> > Is this solution is OK? (The only problem is that adjuacent spaces are > mishandled, but that's fixable). A full solution will need to be a little bit more complicated. There isn't a specification of how Windows command-lines should be generated or interpreted from an array of strings, but it seems to be sensible to interpret them in the same way as Microsoft's run-time library does it: * Outside a quoted section, a double-quote begins a quoted section. * Outside a quoted section, a string of one or more spaces is a separator if there are non-space characters both before and after it; otherwise it's just padding. * Inside a quoted section, a double-quote preceded by an odd number of backslashes (call this n) represents (n-1)/2 backslashes followed by a double-quote. * Inside a quoted section, a double-quote preceded by an even number of backslashes (possibly zero; call this n) represents n/2 backslashes and ends the quoted section. * All other characters represent themselves. Note that double-quotes are not separators and backslashes are not usually escape characters. Also note that a quoted section does not have to be terminated. tokenizer is probably not up to this job. You could probably use regular expressions, but a custom state machine might be the best solution.

2 1

Converting boost::shared_ptr< const T > to boost::shared_ptr< T >
by Alex Tibbles 17 Apr '03

17 Apr '03

Apologies, news editor != text editor (cntrl-enter != autocomplete). I have persistent objects in my appplication and their factory dishes out only constant references (more precisely only copies of a shared_ptr< const T >). In order to make the persistent objects writable, an underlying record needs to be locked in the RDBMS. A friend template instantiation (a WritablePointer< T >) controls this locking, and effectively gives non-const access to the persistent object. The WritablePointer's constructor takes a shared_ptr< const T >. What I want to be able to do is like this (with non-smart pointers): template< typename T > class WritablePointer { public: WritablePointer(const T* const p) : p_(const_cast< T* const >(p)) { p_->lock(); } // ... private: T *p_; }; I have: template< typename T > class WritablePointer { public: typedef typename boost::shared_ptr< T > SmartPointerType; typedef typename boost::shared_ptr< const T > ConstSmartPointerType; WritablePointer(const ConstSmartPointerType& p) : p_(static_cast< const SmartPointerType& >(p)) { p_->lock(); } private: SmartPointerType p_; }; This compiles under gcc 3.2.1 but with a warning: /usr/include/boost/shared_ptr.hpp:153: warning: invalid conversion from `const T* const' to `T*' /usr/include/boost/shared_ptr.hpp: In constructor [I have changed the concrete type from my application to T to simplify]. What I want to do is cast away the const-ness in exactly one place - the WritablePointer ctor. But because I get the warnings it's harder to spot truly illicit conversions. (I copied this technique from an article I read (on Dr. Dobb's or CUJ probably) which used volatile and a mutex to protect shared data between threads, and a smart pointer much like mine to provide write access. I'd be grateful for any suggestions. Alex

2 2

boost:format Problems.
by Bernhard Glück 16 Apr '03

16 Apr '03

Hi ! Today my company switched over to MSVC 1310 ( Visual Studio .NET 2003 ) We make heavy use of some boost libraries. And now we have a real showstopper, boost::format does nto compile anymore without errors. Are there any fixes for that ? we use boost_1_30_0 built using the VC7 toolset ( from MSVC 7.1 ) Here is the code passage that causes errors ( but many others do the same ) // Generate a unique dummy name. boost::format uniqueName("Unknown%1%"); int idNumber = sNames.size() + sIdCounter; // Just an integer. uniqueName % idNumber; Here are the compiler errors: d:\Sdk\boost\boost\format\feed_args.hpp(79) : error C2065: 'disambiguater' : undeclared identifier d:\Sdk\boost\boost\format\feed_args.hpp(140) : see reference to function template instantiation 'void boost::io::detail::`anonymous-namespace'::put_head<char,std::char_traits<char>,T>(std::basic_ostream<_Elem,_Traits> &,const T &)' being compiled with [ T=int, _Elem=char, _Traits=std::char_traits<char> ] d:\Sdk\boost\boost\format\feed_args.hpp(237) : see reference to function template instantiation 'void boost::io::detail::`anonymous-namespace'::put<Ch,Tr,T>(T,const boost::io::detail::format_item<Ch,Tr> &,std::basic_string<_Elem,_Traits,_Ax> &,std::basic_ostringstream<_Elem,_Traits,_Alloc> &)' being compiled with [ Ch=boost::basic_format<char>::CharT, Tr=boost::basic_format<char>::Traits, T=const int &, _Elem=char, _Traits=std::char_traits<char>, _Ax=std::allocator<char>, _Alloc=std::allocator<char> ] d:\Sdk\boost\boost\format\feed_args.hpp(246) : see reference to function template instantiation 'void boost::io::detail::distribute<Ch,Tr,T>(boost::basic_format<Ch> &,T)' being compiled with [ Ch=boost::basic_format<char>::CharT, Tr=boost::basic_format<char>::Traits, T=const int & ] d:\Sdk\boost\boost\format\format_class.hpp(63) : see reference to function template instantiation 'boost::basic_format<Ch> &boost::io::detail::feed<boost::basic_format<Ch>::CharT,boost::basic_format<Ch>::Traits,const T&>(boost::basic_format<Ch> &,const int)' being compiled with [ Ch=char, T=int ] d:\Work\FakedReality\Source\Core\Engine\Identifier.cpp(87) : see reference to function template instantiation 'boost::basic_format<Ch> &boost::basic_format<Ch>::operator %<int>(const T &)' being compiled with [ Ch=char, T=int ] d:\Sdk\boost\boost\format\feed_args.hpp(79) : error C2275: 'Ch' : illegal use of this type as an expression d:\Sdk\boost\boost\format\feed_args.hpp(140) : see declaration of 'Ch' d:\Sdk\boost\boost\format\feed_args.hpp(79) : error C2039: 'put_head' : is not a member of 'operator``global namespace''' d:\Sdk\boost\boost\format\feed_args.hpp(79) : error C2780: 'void boost::io::detail::`anonymous-namespace'::put_head(std::basic_ostream<Ch,Tr> &,const T &)' : expects 2 arguments - 3 provided d:\Sdk\boost\boost\format\feed_args.hpp(78) : see declaration of 'boost::io::detail::`anonymous-namespace'::put_head' d:\Sdk\boost\boost\format\feed_args.hpp(83) : error C2275: 'Ch' : illegal use of this type as an expression d:\Sdk\boost\boost\format\feed_args.hpp(155) : see declaration of 'Ch' d:\Sdk\boost\boost\format\feed_args.hpp(155) : see reference to function template instantiation 'void boost::io::detail::`anonymous-namespace'::put_last<char,std::char_traits<char>,T>(std::basic_ostream<_Elem,_Traits> &,const T &)' being compiled with [ T=int, _Elem=char, _Traits=std::char_traits<char> ] d:\Sdk\boost\boost\format\feed_args.hpp(83) : error C2039: 'put_last' : is not a member of 'operator``global namespace''' d:\Sdk\boost\boost\format\feed_args.hpp(83) : error C2780: 'void boost::io::detail::`anonymous-namespace'::put_last(std::basic_ostream<Ch,Tr> &,const T &)' : expects 2 arguments - 3 provided d:\Sdk\boost\boost\format\feed_args.hpp(82) : see declaration of 'boost::io::detail::`anonymous-namespace'::put_last' d:\Sdk\boost\boost\format\feed_args.hpp(83) : error C3861: 'disambiguater': identifier not found, even with argument-dependent lookup Framework.cpp d:\Sdk\boost\luabind\object.hpp(153) : error C2027: use of undefined type 'luabind::object' d:\Sdk\boost\luabind\object.hpp(90) : see declaration of 'luabind::object' d:\Sdk\boost\luabind\object.hpp(177) : see reference to class template instantiation 'luabind::detail::proxy_caller<Tuple>' being compiled Actor.cpp d:\Sdk\boost\luabind\object.hpp(153) : error C2027: use of undefined type 'luabind::object' d:\Sdk\boost\luabind\object.hpp(90) : see declaration of 'luabind::object' d:\Sdk\boost\luabind\object.hpp(177) : see reference to class template instantiation 'luabind::detail::proxy_caller<Tuple>' being compiled Log.cpp d:\Sdk\boost\boost\format\feed_args.hpp(79) : error C2065: 'disambiguater' : undeclared identifier d:\Sdk\boost\boost\format\feed_args.hpp(140) : see reference to function template instantiation 'void boost::io::detail::`anonymous-namespace'::put_head<char,std::char_traits<char>,T>(std::basic_ostream<_Elem,_Traits> &,const T &)' being compiled with [ T=int, _Elem=char, _Traits=std::char_traits<char> ] d:\Sdk\boost\boost\format\feed_args.hpp(237) : see reference to function template instantiation 'void boost::io::detail::`anonymous-namespace'::put<Ch,Tr,T>(T,const boost::io::detail::format_item<Ch,Tr> &,std::basic_string<_Elem,_Traits,_Ax> &,std::basic_ostringstream<_Elem,_Traits,_Alloc> &)' being compiled with [ Ch=boost::basic_format<char>::CharT, Tr=boost::basic_format<char>::Traits, T=const int &, _Elem=char, _Traits=std::char_traits<char>, _Ax=std::allocator<char>, _Alloc=std::allocator<char> ] d:\Sdk\boost\boost\format\feed_args.hpp(246) : see reference to function template instantiation 'void boost::io::detail::distribute<Ch,Tr,T>(boost::basic_format<Ch> &,T)' being compiled with [ Ch=boost::basic_format<char>::CharT, Tr=boost::basic_format<char>::Traits, T=const int & ] d:\Sdk\boost\boost\format\format_class.hpp(63) : see reference to function template instantiation 'boost::basic_format<Ch> &boost::io::detail::feed<boost::basic_format<Ch>::CharT,boost::basic_format<Ch>::Traits,const T&>(boost::basic_format<Ch> &,const int)' being compiled with [ Ch=char, T=int ] d:\Work\FakedReality\Source\Core\Debug\Log.cpp(114) : see reference to function template instantiation 'boost::basic_format<Ch> &boost::basic_format<Ch>::operator %<int>(const T &)' being compiled with [ Ch=char, T=int ] d:\Sdk\boost\boost\format\feed_args.hpp(79) : error C2275: 'Ch' : illegal use of this type as an expression d:\Sdk\boost\boost\format\feed_args.hpp(140) : see declaration of 'Ch' d:\Sdk\boost\boost\format\feed_args.hpp(79) : error C2039: 'put_head' : is not a member of 'operator``global namespace''' d:\Sdk\boost\boost\format\feed_args.hpp(79) : error C2780: 'void boost::io::detail::`anonymous-namespace'::put_head(std::basic_ostream<Ch,Tr> &,const T &)' : expects 2 arguments - 3 provided d:\Sdk\boost\boost\format\feed_args.hpp(78) : see declaration of 'boost::io::detail::`anonymous-namespace'::put_head' d:\Sdk\boost\boost\format\feed_args.hpp(83) : error C2275: 'Ch' : illegal use of this type as an expression d:\Sdk\boost\boost\format\feed_args.hpp(155) : see declaration of 'Ch' d:\Sdk\boost\boost\format\feed_args.hpp(155) : see reference to function template instantiation 'void boost::io::detail::`anonymous-namespace'::put_last<char,std::char_traits<char>,T>(std::basic_ostream<_Elem,_Traits> &,const T &)' being compiled with [ T=int, _Elem=char, _Traits=std::char_traits<char> ] d:\Sdk\boost\boost\format\feed_args.hpp(83) : error C2039: 'put_last' : is not a member of 'operator``global namespace''' d:\Sdk\boost\boost\format\feed_args.hpp(83) : error C2780: 'void boost::io::detail::`anonymous-namespace'::put_last(std::basic_ostream<Ch,Tr> &,const T &)' : expects 2 arguments - 3 provided d:\Sdk\boost\boost\format\feed_args.hpp(82) : see declaration of 'boost::io::detail::`anonymous-namespace'::put_last' d:\Sdk\boost\boost\format\feed_args.hpp(83) : error C3861: 'disambiguater': identifier not found, even with argument-dependent lookup State.cpp d:\Sdk\boost\luabind\object.hpp(153) : error C2027: use of undefined type 'luabind::object' d:\Sdk\boost\luabind\object.hpp(90) : see declaration of 'luabind::object' d:\Sdk\boost\luabind\object.hpp(177) : see reference to class template instantiation 'luabind::detail::proxy_caller<Tuple>' being compiled d:\Sdk\boost\boost\iterator_adaptors.hpp(1409) : see reference to class template instantiation 'boost::filter_iterator_generator<Predicate,Iterator,Value,Reference,Pointer,Category,Distance>' being compiled d:\Work\FakedReality\Source\Core\Scripting\State.cpp(303) : error C3861: 'lua_dostring': identifier not found, even with argument-dependent lookup Script.cpp d:\Sdk\boost\luabind\object.hpp(153) : error C2027: use of undefined type 'luabind::object' d:\Sdk\boost\luabind\object.hpp(90) : see declaration of 'luabind::object' d:\Sdk\boost\luabind\object.hpp(177) : see reference to class template instantiation 'luabind::detail::proxy_caller<Tuple>' being compiled IScriptExport.cpp d:\Sdk\boost\luabind\object.hpp(153) : error C2027: use of undefined type 'luabind::object' d:\Sdk\boost\luabind\object.hpp(90) : see declaration of 'luabind::object' d:\Sdk\boost\luabind\object.hpp(177) : see reference to class template instantiation 'luabind::detail::proxy_caller<Tuple>' being compiled Type.cpp d:\Sdk\boost\luabind\object.hpp(153) : error C2027: use of undefined type 'luabind::object' d:\Sdk\boost\luabind\object.hpp(90) : see declaration of 'luabind::object' d:\Sdk\boost\luabind\object.hpp(177) : see reference to class template instantiation 'luabind::detail::proxy_caller<Tuple>' being compiled IConverter.cpp d:\Sdk\boost\luabind\object.hpp(153) : error C2027: use of undefined type 'luabind::object' d:\Sdk\boost\luabind\object.hpp(90) : see declaration of 'luabind::object' d:\Sdk\boost\luabind\object.hpp(177) : see reference to class template instantiation 'luabind::detail::proxy_caller<Tuple>' being compiled Version.cpp d:\Sdk\boost\boost\format\feed_args.hpp(79) : error C2065: 'disambiguater' : undeclared identifier d:\Sdk\boost\boost\format\feed_args.hpp(140) : see reference to function template instantiation 'void boost::io::detail::`anonymous-namespace'::put_head<char,std::char_traits<char>,T>(std::basic_ostream<_Elem,_Traits> &,const T &)' being compiled with [ T=int, _Elem=char, _Traits=std::char_traits<char> ] d:\Sdk\boost\boost\format\feed_args.hpp(237) : see reference to function template instantiation 'void boost::io::detail::`anonymous-namespace'::put<Ch,Tr,T>(T,const boost::io::detail::format_item<Ch,Tr> &,std::basic_string<_Elem,_Traits,_Ax> &,std::basic_ostringstream<_Elem,_Traits,_Alloc> &)' being compiled with [ Ch=boost::basic_format<char>::CharT, Tr=boost::basic_format<char>::Traits, T=const int &, _Elem=char, _Traits=std::char_traits<char>, _Ax=std::allocator<char>, _Alloc=std::allocator<char> ] d:\Sdk\boost\boost\format\feed_args.hpp(246) : see reference to function template instantiation 'void boost::io::detail::distribute<Ch,Tr,T>(boost::basic_format<Ch> &,T)' being compiled with [ Ch=boost::basic_format<char>::CharT, Tr=boost::basic_format<char>::Traits, T=const int & ] d:\Sdk\boost\boost\format\format_class.hpp(63) : see reference to function template instantiation 'boost::basic_format<Ch> &boost::io::detail::feed<boost::basic_format<Ch>::CharT,boost::basic_format<Ch>::Traits,const T&>(boost::basic_format<Ch> &,const int)' being compiled with [ Ch=char, T=int ] d:\Work\FakedReality\Source\Core\Platform\Win32\Version.cpp(38) : see reference to function template instantiation 'boost::basic_format<Ch> &boost::basic_format<Ch>::operator %<int>(const T &)' being compiled with [ Ch=char, T=int ] d:\Sdk\boost\boost\format\feed_args.hpp(79) : error C2275: 'Ch' : illegal use of this type as an expression d:\Sdk\boost\boost\format\feed_args.hpp(140) : see declaration of 'Ch' d:\Sdk\boost\boost\format\feed_args.hpp(79) : error C2039: 'put_head' : is not a member of 'operator``global namespace''' d:\Sdk\boost\boost\format\feed_args.hpp(79) : error C2780: 'void boost::io::detail::`anonymous-namespace'::put_head(std::basic_ostream<Ch,Tr> &,const T &)' : expects 2 arguments - 3 provided d:\Sdk\boost\boost\format\feed_args.hpp(78) : see declaration of 'boost::io::detail::`anonymous-namespace'::put_head' d:\Sdk\boost\boost\format\feed_args.hpp(83) : error C2275: 'Ch' : illegal use of this type as an expression d:\Sdk\boost\boost\format\feed_args.hpp(155) : see declaration of 'Ch' d:\Sdk\boost\boost\format\feed_args.hpp(155) : see reference to function template instantiation 'void boost::io::detail::`anonymous-namespace'::put_last<char,std::char_traits<char>,T>(std::basic_ostream<_Elem,_Traits> &,const T &)' being compiled with [ T=int, _Elem=char, _Traits=std::char_traits<char> ] d:\Sdk\boost\boost\format\feed_args.hpp(83) : error C2039: 'put_last' : is not a member of 'operator``global namespace''' d:\Sdk\boost\boost\format\feed_args.hpp(83) : error C2780: 'void boost::io::detail::`anonymous-namespace'::put_last(std::basic_ostream<Ch,Tr> &,const T &)' : expects 2 arguments - 3 provided d:\Sdk\boost\boost\format\feed_args.hpp(82) : see declaration of 'boost::io::detail::`anonymous-namespace'::put_last' d:\Sdk\boost\boost\format\feed_args.hpp(83) : error C3861: 'disambiguater': identifier not found, even with argument-dependent lookup Generating Code...

4 4

uBlas Lapack binds - part 2
by geert_ceuppens 16 Apr '03

16 Apr '03

I realise that the binding will need quite some work to get right under VC6 (see previous posting). I would welcome suggestions to do the conversion directly (so without all the traits stuff) and not as general. Goal would be to quickly start and then (hopefully) one day be able to migrate to the traits version. Maybe the getrf function in Lapack would be a good starting point? Thanks ... By the way Toon, I think there is a typo in lapack.hpp: template < typename matrix_type, typename IpivIterator > int getrf(matrix_type& a, IpivIterator begin_ipiv, IpivIterator end_ipiv) { using namespace boost::numeric::bindings::traits ; typedef typename matrix_type::value_type value_type ; typedef typename boost::numeric::bindings::traits::value_traits< value_type >::value_type bind_type ; int m = boost::numeric::bindings::traits::matrix_size1( a ) ; int n = boost::numeric::bindings::traits::matrix_matrix_size2( a ) ; Shouldn't matrix_matrix_size2 be matrix_size2? (I can't compile so I did a visual compilation ;^) ... Rgds Geert

3 2

big int library
by Vaclav Vesely 16 Apr '03

16 Apr '03

Are there any plans about adding a big int library to the Boost? There are at least two implementations in the Sandbox. Thanks, w

2 1

command line parsing
by cl_corba_at 16 Apr '03

16 Apr '03

What is the "boost way" of parsing command line arguments? When I searched the archives, some user recommended spirit for this task, but this seems to heavy-weighted for me. I tried tokenizer, but a seperator for the command line is not provided. - you have to remove quotations marks (only escaped_list_separator can do this) - your have to ignore multiple tokens (only char_seperator can do this) If I write this seperator its still wouldn't provide the api I would like to see for a command line parser. I saw in the past there have been an attemp by Bill Kempf to provide a command line parser for boost but it didn't find its way into the library from reasons I don't know. So is there a recommended way to parse options I did overlook? Is a command line parser planned? Thanks for your answers, CL

5 8

GNU istream::scan
by Pat McCormack 15 Apr '03

15 Apr '03

Hi Is there anything like the GNU extension istream::scan() (to use a scanf style format string) in the Boost libraries? The boost format library seems designed to work solely on output streams (am I right on this?) Thanks Pat

1 0

RE: [Boost-Users] Boost weak_ptr<>
by bjorn.karlsson＠readsoft.com 15 Apr '03

15 Apr '03

> From: Edward Diener [mailto:eddielee@tropicsoft.com] > > I don't understand what the practical use of Boost weak_ptr<> > is ? Anyone > like to clue me in ? I understand that Boost weak_ptr<> > creates an internal > reference to a Boost shared_ptr<> but I don't understand what that is > supposed to accomplish. A weak_ptr is an observer of the pointee, i.e it doesn't take part of the lifetime management of the resource. One use for it is to break cyclic dependencies; another is to avoid dangling pointers. When a shared_ptr deallocates its pointee, it notifies the weak_ptrs. When the weak_ptr is subsequently used, it knows that the resource is gone (compare this with storing raw pointers, where there is no way to tell whether the pointer is still valid or not). Example: A Company class has a container that holds elements of type shared_ptr<Employee>. Now, the Supervisor class needs to know things about certain Employees, but it cannot/must not control their lifetime (in the context of the Company class, that is). Rather than asking the Company to search through each Employee (for example by name) each time Supervisor needs to access/update some Employee information, it caches information in weak_ptr<Employee> for efficient access. If an Employee quits (is removed from the container of shared_ptr<Employee>), the Supervisor class will be informed of this the next time it tries to access that weak_ptr<Employee>. At the time of access, a (temporary) shared_ptr is created from a weak_ptr, to ensure that the pointee isn't deleted in the midst of using it. Without weak_ptr, the above would be hard(er) to accomplish: * Asking Company to find an Employee each time it is needed may be too inefficient. * Storing shared_ptr<Employee> in the Supervisor class interferes with lifetime management and can cause inconsistent state. * Storing a raw pointer to an Employee is extremely dangerous (known as the dangling Employee problem); there's no way of telling if the pointer is valid. Bjorn Karlsson

2 1

shard_ptr
by Christian Gmeiner 15 Apr '03

15 Apr '03

Hi! I want to use boost's shared_ptr in my project, which is a dll. At the moment it looks like this: in the h: extern MY_API CCPUDetect * gCPU; in the cpp: CCPUDetect * gCPU = CCPUDetect::GetInstance(); I have problems to make the same with boost, so that gCPU is a smartpointer. Thanks, Christian Gmeiner [Non-text portions of this message have been removed]

2 1

Boost weak_ptr<>
by Edward Diener 15 Apr '03

15 Apr '03

I don't understand what the practical use of Boost weak_ptr<> is ? Anyone like to clue me in ? I understand that Boost weak_ptr<> creates an internal reference to a Boost shared_ptr<> but I don't understand what that is supposed to accomplish.

2 1

boost::date_time don't work under Kylix
by Konstantin M. Litvinenko 15 Apr '03

15 Apr '03

Hello, All! #include <boost/date_time/posix_time/posix_time.hpp> #include <iostream> int main() { using namespace boost::posix_time; using namespace boost::gregorian; date d(1990,1,1); ptime t(d); std::cout << to_simple_string(t); return 0; } I have tested this sample under 4 compilers - vc7, gcc 2.96 asplinux, builder 5.6.4 and kylix3 (compiler borland 5.6). Under Kylix it produce floating point error. I figure out that this happens because t, after this line ptime t(date(1990,1,1)); have {0} (as i see in debuger). Is this library or kylix bug? It seems to be a __int64 arithmetic error but i am not sure. With best regards, Konstantin M. Litvinenko aka Dark Angel. E-mail: darkangel(a)malva.ua

2 2

Question about SPirit parser terminology
by satya_vajja 14 Apr '03

14 Apr '03

Can anyone explain me what is the difference between a rule, grammar and parser in SPIRIT parser library. Thanks

2 1

Macintosh Carbon Thread Error with Boost 1.30.0
by Bobby Thomale 14 Apr '03

14 Apr '03

Hey guys, I just tried to get the new Boost 1.30.0 release to work on MacOS, using TARGET_CARBON (with threads turned on). I have a problem to report: there's a new "lightweight mutex" being used by the smart pointer library. There does not seem to be a lightweight mutex implementation for the "Carbon MP tasks" thread implementation. So - when I compile my code under Boost 1.30 I end up at: # error Unrecognized threading platform in lightweight_mutex.hpp when it tries to compile any of the smart pointer stuff. Help! :-) -- Bobby --------------------------------------------------------------------- Bobby Thomale Senior Software Developer Inoveon Corporation http://www.inoveon.com/ ---------------------------------------------------------------------

2 3

uBlas Lapack binds from Sandbox - pb with templ. specialisation
by geert_ceuppens 14 Apr '03

14 Apr '03

Toon & Kresimir, I've downloaded the lapack and blas binds from the boost sandbox, and I found out the hard way (again :^( ...) the 'features' of the VC6 compiler, i.e. the lack of support for template specialisation. The offending code is: (line nbr may differ due to versioning) *) boost\numeric\bindings\traits\algorithm.hpp(45): template < typename T > struct is_equal vs: template < typename T > struct is_equal< boost::numeric::ublas::matrix< T > > --> template class has already been defined as a non-template class *) libs\numeric\bindings\blas\test\blas.hpp(51): template < typename T > struct assign_multiplier vs: template < typename T > struct assign_multiplier< std::complex< T > > *) boost\numeric\bindings\traits\traits.hpp(46): template <typename V, typename T = typename V::value_type> struct default_vector_traits vs: template <typename V, typename T> struct default_vector_traits<V const, T> *) boost\numeric\bindings\traits\traits.hpp(112 & 114): This one gave more errors: template <typename MatrixT> inline typename matrix_traits<MatrixT>::pointer matrix_storage (MatrixT& m) { return matrix_traits<MatrixT>::storage (m); } error C2039: 'pointer' : is not a member of 'matrix_traits<M>' error C2146: syntax error : missing ';' before identifier 'matrix_storage' error C2433: 'pointer' : 'inline' not permitted on data declarations error C2501: 'pointer' : missing storage-class or type specifiers error C2059: syntax error : ';' error C2065: 'MatrixT' : undeclared identifier error C2065: 'm' : undeclared identifier 'matrix_storage' : missing storage-class or type specifiers syntax error : missing ';' before '<end Parse>' Any chance of providing non-specialised versions of these so I can use the VC6 compiler? Thanks - Geert

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RE: [Boost-Users] command line parsing
by Jim.Hyslop 14 Apr '03

14 Apr '03

Joe Mariadassou [mailto:joemar@vcisnet.net] wrote: > The URL appears to be invalid. > joe > > -----Original Message----- > From: HartmutKaiser(a)t-online.de [mailto:HartmutKaiser@t-online.de] > Sent: Monday, April 14, 2003 3:04 AM > To: Boost-Users(a)yahoogroups.com > Subject: RE: [Boost-Users] command line parsing > > > As far as I remember Vladimir Prus has requested Boost review for his > program_options library. You can find it here: > > http://zigzag.cs.msu.su:7813/program_options > Works OK for me - maybe the problem is temporary. -- Jim

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test
by iad929 13 Apr '03

13 Apr '03

plz ignore. Mohammed

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RE: [Boost-Users] Unary predicate for shared_ptr == 'real' pointe r?
by dick.bridges＠tais.com 11 Apr '03

11 Apr '03

Thanks! In a sense, I can sympathize with your co-workers. I spent hours trying to get that predicate right - I kept screwing up the 'inner' bind. I keep hoping the more I work with the boost libraries the easier it will get. In my case, that's yet to be seen. ;) Thanks again. Tom Matelich <tmatelich@zetec To: "'Boost-Users(a)yahoogroups.com'" <Boost-Users(a)yahoogroups.com> .com> cc: Subject: RE: [Boost-Users] Unary predicate for shared_ptr == 'real' pointe r? 04/11/2003 01:55 PM Please respond to Boost-Users > From: Mark Storer [mailto:mstorer@cardiff.com] > Sent: Friday, April 11, 2003 1:51 PM > > The whole "new int" thing seems a little odd, but that's an > artifact of creating example code. precisely > What do your co-workers say? I feel like I'm missing something here. While the elegance of the double bind is appreciated, I've heard complaints about it being confusing. ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. ----------------------------------------------------------------------- Info: <http://www.boost.org> Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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RE: [Boost-Users] Unary predicate for shared_ptr == 'real' pointe r?
by Tom Matelich 11 Apr '03

11 Apr '03

> From: Mark Storer [mailto:mstorer@cardiff.com] > Sent: Friday, April 11, 2003 1:51 PM > > The whole "new int" thing seems a little odd, but that's an > artifact of creating example code. precisely > What do your co-workers say? I feel like I'm missing something here. While the elegance of the double bind is appreciated, I've heard complaints about it being confusing. ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------

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RE: [Boost-Users] Unary predicate for shared_ptr == 'real' pointe r?
by Mark Storer 11 Apr '03

11 Apr '03

The whole "new int" thing seems a little odd, but that's an artifact of creating example code. What do your co-workers say? I feel like I'm missing something here. --Mark Storer Software Engineer Cardiff Software #include <disclaimer> typedef std::disclaimer<Cardiff> Discard;

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RE: [Boost-Users] Unary predicate for shared_ptr == 'real' pointe r?
by Tom Matelich 11 Apr '03

11 Apr '03

> From: dick.bridges(a)tais.com [mailto:dick.bridges@tais.com] > Sent: Friday, April 11, 2003 11:54 AM > > This is probably more of a C++ than an boost question but, since it > involves shared_ptr, I thought I'd try it here first. I've > got a vector of > shared_ptrS (e.g., vector<shared_ptr<T> > v;) and I need to > find the entry > given the 'real' pointer to the underlying T. Looping thru > the vector like > this: > > <snippet> > for( vector<shared_ptr<T>::iterator itr = v.begin(); itr != > v.end(); itr++) > { > if( itr->get() == real_this){...} > } > </snippet> > > works but seems klunky. I should be able to use [find_if( > v.begin(), v.end > (), ???)] but I can't work out the predicate. Any help or > "pointers" ;) > will be greatly appreciated. > Here's how I like to do it, though my co-workers sometimes complain: #include "boost/shared_ptr.hpp" #include "boost/bind.hpp" #include <vector> #include <iostream> int main() { typedef std::vector<boost::shared_ptr<int> > V; V vec; int* foo = new int; vec.push_back(boost::shared_ptr<int>(foo)); V::iterator iter = std::find_if(vec.begin(), vec.end(), boost::bind(std::equal_to<int*>(), boost::bind(&boost::shared_ptr<int>::get, _1), foo)); if(iter != vec.end()) std::cout << "Life is good" << std::endl; //don't delete foo!!! return 0; } Tom ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------

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Unary predicate for shared_ptr == 'real' pointer?
by dick.bridges＠tais.com 11 Apr '03

11 Apr '03

This is probably more of a C++ than an boost question but, since it involves shared_ptr, I thought I'd try it here first. I've got a vector of shared_ptrS (e.g., vector<shared_ptr<T> > v;) and I need to find the entry given the 'real' pointer to the underlying T. Looping thru the vector like this: <snippet> for( vector<shared_ptr<T>::iterator itr = v.begin(); itr != v.end(); itr++) { if( itr->get() == real_this){...} } </snippet> works but seems klunky. I should be able to use [find_if( v.begin(), v.end (), ???)] but I can't work out the predicate. Any help or "pointers" ;) will be greatly appreciated. TIA

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RE: [Boost-Users] Boost random's min < max assert
by Glen Knowles 11 Apr '03

11 Apr '03

From: Jens Maurer >> Uniform int contains an assert if min < max. If I ask for a random between 1 >> and 1 I'm expecting a 1, not an assert. Is there some reason this was deemed >> inappropriate? > >When I wrote that code, I never thought somebody would want to generate >a constant 1 as a random number. I agree that this looks non-orthogonal >on first sight. I'll look into it. In my specific case I have a number of objects determined at run time and am randomly picking a number between one and the number of objects in order to select one. The workaround is to simply test for one before the call, but the assert was unexpected. Thanks, Glen [Non-text portions of this message have been removed]

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RE: [Boost-Users] Problem with boost::pool_alloc
by scleary＠jerviswebb.com 11 Apr '03

11 Apr '03

> -----Original Message----- > From: Ilya Chvetsov(work) [mailto:chvetsov@kdlab.com] > > Hi! > I try to use boost::pool_alloc with STLport-4.5-0119 snapshot. > STLPort call pool_alloc::allocate(const size_type n) with n = 0. > STLPort naitive allocator returns in such case NULL, but pool_alloc > tries return memory. Hmmm... You seem to have uncovered a corner case, not covered by the Standard requirements. I will change the pool_allocator (and fast_pool_allocator) to be able to handle this by returning NULL. > Method simple_segregated_storage<SizeType>::try_malloc_n( > void * & start, size_type n, const size_type partition_size) has > problem too if parameter n is 0. Problem is in while condition: > while (--n != 0)... This is correct; (n > 0) is a precondition for that function. -Steve

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