- Boost-users - lists.boost.org

Re: [Boost-users] The boost Tokenizer package: split into a vectorof vectors of tokens
by Alex Vinokur 30 Dec '05

30 Dec '05

Pavol Droba wrote: > On Sat, Dec 24, 2005 at 09:06:51AM +0200, Alex Vinokur wrote: > > > > "Pavol Droba" <droba(a)topmail.sk> wrote in message news:20051223180408.GP15407@lenin.felcer.sk... > > > Hi, > > > > > > You might be able to do it using the string_algo find_iterator. > > > > > > #include <boost/algorithm/string.hpp> > > > > > > using namespace std; > > > using namespace boost; > > > > > > ... > > > > > [snip] > > typedef split_iterator<string::iterator> string_find_iterator; > > ------------------------------------------------------------------------------ > > > string_find_iterator It=make_find_iterator(str1, token_finder(is_space())); > > > > That line produces the following error message: > > > > error: conversion from `boost::algorithm::find_iterator<__gnu_cxx::__normal_iterator<char*, std::basic_string<char, > > std::char_traits<char>, std::allocator<char> > > >' to non-scalar type > > `boost::algorithm::split_iterator<__gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, > > std::allocator<char> > > >' requested > > > > Sorry, I have fixed one error, but the other line was tied to it. > the second line should be > string_find_iterator It=make_split_iterator(str1, token_finder(is_space())); > > Regards, > Pavol Thanks. Here is what I compiled: -------- #include<iostream> #include<boost/tokenizer.hpp> #include<boost/algorithm/string.hpp> #include<string> using namespace std; using namespace boost; void test() { string s = "ab cd \n xy z\n123"; typedef split_iterator<string::iterator> string_find_iterator; string_find_iterator It = make_split_iterator(s, token_finder(is_space())); const int maxi = 3; const int maxj = 2; for(int i=0; i < maxi; i++) { for(int j=0; j < maxj; j++) { if(It != string_find_iterator()) cout << "(" << i << ", " << j << ") : " << (*It) << endl; else break; } } } int main () { test(); return 0; } -------- And here is what I have got after running: --- (0, 0) : ab (0, 1) : ab (1, 0) : ab (1, 1) : ab (2, 0) : ab (2, 1) : ab --- Alex Vinokur email: alex DOT vinokur AT gmail DOT com http://mathforum.org/library/view/10978.html http://sourceforge.net/users/alexvn

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[iostreams] array_sink full exception
by Robert Ramey 30 Dec '05

30 Dec '05

I'm looking at array_sink stream buffer as a possible speed enhancement to binary_oarchive in some cases. My quesion is" What happens when the capacity of the array used for the buffer is exceeded? Is an exception thrown or what? I've looked through the documentation and don't find exceptions mentioned. Robert Ramey

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Re: [Boost-users] [Multi-index] Sorted range selection
by JOAQUIN LOPEZ MU?Z 29 Dec '05

29 Dec '05

Hello Tamas, ----- Mensaje original ----- De: Tamas Szepes <tamas.szepes(a)ieee.org> Fecha: Miércoles, Diciembre 28, 2005 9:11 pm Asunto: [Boost-users] [Multi-index] Sorted range selection > Hi All, > > I'm learning to use the multi-index library by rewriting an > existing STL > based code. > I'm storing rectangles (X, Y, Width, Height, ...) in a set ordered > by a > composite key on X, Y. > > What is the best way to select rectangles where X has a certain > value and > sort the result by Width? Can I use a sorted indice on Width, or I > must sort > the range? I also thought to create a composite key on X and > Width, but > sorting order is run time determined and I have a dosen other > properties. Your analysis is correct. I'm afraid you have to externally sort the interval returned by range(), pseudocode follows: std::vector<boost::reference_wrapper<const Rectangle> > rng; std::pair< YourCompositeKeyIndex::iterator, YourCompositeKeyIndex::iterator> p= yourcompositekeyindex.range(...); while(p.first!=p.second)rng.push_back(boost::cref(*p.first++)); std::sort(rng.begin(),rng.end(),WidthCompare()); Having a composite key on (X,Width) is also an option, but as you say the number of combinations might be too large, and manipulating those indices with run-time decisions is not trivial. So, my suggestion is to follow the scheme proposed on the pseudocode above. > I'm realy looking for the possibility to mimic SQL's ORDER BY clause. Well, Boost.MultiIndex does not aim to provide complete functionality for relational stuff, as stated explicitly in the rationale at http://boost.org/libs/multi_index/doc/tutorial.html. The idea is to keep Boost.MultiIndex application-agnostic and more focused on the STL conceptual framework. As I see it, this kind of funcionality could be better served by a relational-specific lib built on top of Boost.MultiIndex. There are currently two libs approaching this goal, Arkadiy Vertleyb's RTL and Calum Grant's RML (look for those on recent discussions on the Boost list.) Unfortunately, neither of these libs actually uses internally Boost.MultiIndex, but this is another story :) > > Thanks for any help in advance, I'm sorry I can't be more helpful. Thanks for using Boost.MultiIndex and please come back if you have further problems or want to comment on proposals for enhancements of the library. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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BGL question: non local exit by throwing an exception
by Andreas Fabri 29 Dec '05

29 Dec '05

Hi, I am wondering, if it is good style to throw an exception in the middle of a BGL algorithm, for example during BFS when I have found what I want. Or are there nicer ways to achive the same goal? Thanks in advance, andreas

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[BGL] Mixing bundled properties and property lists
by Nicola Vitacolonna 29 Dec '05

29 Dec '05

Hi, consider the following (excerpt from a) class wrapper around an adjacency_list: using namespace boost; template <typename VertexProperty = no_property> class MyGraphWrapper { private: typedef adjacency_list<vecS, listS, bidirectionalS, property<vertex_index_t, int, VertexProperty> > GraphImpl; // ... }; I want to store some property (in this case, a vertex index) inside the graph implementation, but at the same time I want to allow the client to specify further properties via the template parameter. May the client use the bundled property mechanism, e.g. struct Label { std::string lab; }; MyGraphWrapper<Label> g; My test compiled and it seems to run fine. Is it really possible/safe to mix bundle properties with property lists in this way? Or, is there a way to avoid property lists? Nicola

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Re: [Boost-users] [boost] bug in signals library? - segmentation fault (onlylinked) -> exit(11) called
by Oliver.Kowalke＠infineon.com 29 Dec '05

29 Dec '05

Hi, Strange - the segmentation fault disappears if I link with the debug-version of libboost_signals (-lboost_signals-gcc-d-1_33_1)! It seams to me that some assert statements contain required code (removed in release version if signals)?! >> I get an segmentation fault if I try to link against >> libboost_signals-gcc-1_33_1 or libboost_signals-gcc-mt-1_33_1! >> The application consist only of an empty main function and the binary is >> linked against the signals library. >> I've appended an output (tusc.out) of tusc (trace unix system calls) >> which indicates, that exit(11) is called and so a core dump created. > >Can you run the program under gdb debugger, and when hittin segfault >produce >backtrace with the "backtrace" command. That will be more usefull, in any >case, then syscall trace. I'm not familiar with gdb! What I did (hopefully correct): [src]$ /opt/langtools/bin/gdb32 test HP gdb 5.2 for PA-RISC 1.1 or 2.0 (narrow), HP-UX 11.00 and target hppa1.1-hp-hpux11.00. Copyright 1986 - 2001 Free Software Foundation, Inc. Hewlett-Packard Wildebeest 5.2 (based on GDB) is covered by the GNU General Public License. Type "show copying" to see the conditions to change it and/or distribute copies. Type "show warranty" for warranty/support. .. (gdb) run Starting program: /eda-home/kowalke/Projects/test/debug/src/test Program received signal SIGSEGV, Segmentation fault si_code: 0 - SEGV_UNKNOWN - Unknown Error. 0xc0017cd8 in <unknown_procedure> () (gdb) backtrace #0 0xc0017cd8 in <unknown_procedure> () warning: Attempting to unwind past bad PC 0xc0017cd8 #1 0xc0027400 in <unknown_procedure> () #2 0xc0027400 in <unknown_procedure> () Error accessing memory address 0x3e7: Bad address.

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boost: debug step into extremely slow at VC8
by David Xiao 29 Dec '05

29 Dec '05

Hi Guys: In my computer, if compile with VC8 with boost library, the debug stepping speed is extremely slow! I have to wait 3-5 second for one step! With VC7.1 everything is ok. Who has the same problem with me ? Rgds, David Xiao

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[Multi-index] Sorted range selection
by Tamas Szepes 28 Dec '05

28 Dec '05

Hi All, I'm learning to use the multi-index library by rewriting an existing STL based code. I'm storing rectangles (X, Y, Width, Height, ...) in a set ordered by a composite key on X, Y. What is the best way to select rectangles where X has a certain value and sort the result by Width? Can I use a sorted indice on Width, or I must sort the range? I also thought to create a composite key on X and Width, but sorting order is run time determined and I have a dosen other properties. I'm realy looking for the possibility to mimic SQL's ORDER BY clause. Thanks for any help in advance, Tamas

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cannot open file 'libboost_date_time-vc71-sgd-1_33_1.lib'
by Subrahmanyam (Arun) 28 Dec '05

28 Dec '05

Hi, I am new to boost libraries. I have viewed some samples in http://www.boost.org/doc/html/date_time/examples.html#date_time.examples.da… in which i tried to build "Days Alive" example. The application reports: boost1 fatal error LNK1104: cannot open file 'libboost_date_time-vc71-sgd-1_33_1.lib' I have searched this in my list of libraries/files installed, but failed to find the same. Can any one please help how to overcome this error. Thanks, Arun.

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Re: [Boost-users] [serialization]Mal-formed XML output
by Merrill Cornish 28 Dec '05

28 Dec '05

Robert, I changed the archive output from XML to text. The example I sent you prevously ran to completion without error. However, the text format doesn't have enough syntax detail to make a syntax error obvious. The text archive it generated was 22 serialization::archive 3 0 1 1 1 0 0 0 0 0 1 -1 4 abcd 0 0 0 0 8 20051227 0 0 0 18 41 40 0 I had also written a serialization test for another class. Its serialize() function looks like this private: friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const unsigned int version) { ar & BOOST_SERIALIZATION_NVP(mNode); ar & BOOST_SERIALIZATION_NVP(mInputIndex); ar & BOOST_SERIALIZATION_NVP(mIsInbound); }//serialize() where, again, mNode is a shared_ptr, mInputIndex is size_t, and mIsInbound is a bool. The code to generate the archive and to then read is back is as I showed you before. The archive generated was 22 serialization::archive 3 0 1 1 1 0 0 0 1 Is that enough of an archive to record the serialize() function above? The serialization of the mNode data member should have included the value 1142 in it, but I see nothing that would represent that. Merrill

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