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[iostreams] Obfuscator
by Robert Bielik 22 Apr '08

22 Apr '08

Hi all, I'm trying to make filter to obfuscate some data so its not that obvious what it is. Problem is (I think) that in some cases, the obfuscator produces a null character as its output, and I'm not sure, but it seems that upon reading back the data, the null character is interpreted as EOF. At least, that is what I get from boost::iostreams::get(src) at the position where the null character was in the output. Can I somehow tell the stream that it is binary and not care about null characters? TIA /Rob

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Re: [Boost-users] Applying Boost license to non boost projects
by Robert Marion 22 Apr '08

22 Apr '08

You may wish to consider applying the liberal BSD (http://www.opensource.org/licenses/bsd-license.php) or MIT (http://www.opensource.org/licenses/mit-license.php) licenses. These are both in widespread use for open source, and impose no restrictions, aside from attribution, on the user. Putting the license text at the top of all headers is not strictly necessary, but not a bad idea. Robert Marion http://www.palamida.com > I am interested in adopting the Boost Software license for an open source C++ > library (Castor: http://www.mpprogramming.com/2.html) > > [ snip ] > - Does this same guideline apply to non boost projects ? The need for stating > Boost.org there might confuse some users of non boost prj to think that the > library is supplied by Boost. > - Do all header files in my prj (which is a pure header library) need to > include this text at the top/somewhere in order to adopt the license. > > -Roshan

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[BGL] implicit astar_search weirdness, bug in mutable_queue?
by Oliver Seiler 21 Apr '08

21 Apr '08

Hi there -- long-time reader, first-time poster! I've been trying to use astar_search from the graph library for a little problem I'm working on. Specifically, I wanted to use it to perform a search on an implicit graph (more specifically, an implicit tree), as touched on briefly in the docs for astar_search. In this case, I'm using boost 1.33.1 Unfortunately, this doesn't appear to be well supported "out of the box". Google didn't turn up much on the subject, except for a paper done by Kris Beevers and Jufeng Peng (www.cs.rpi.edu/~beevek/research/astar_bgl04.pdf) which mentions the need for a non-const version of the breadth-first search code in BGL, and a message to the list from Ian Downes, Feb 28th, asking about doing an implicit search as well (couldn't find any followups). Using Beevers paper as a template, I started bumping into some serious memory corruptions problems with my test-cases. Finally today I ran the tests under valgrind and managed to track it down to mutable_queue (boost/pending/mutable_queue.hpp), which is used by the astar_search code to manage the set of partial solutions. mutable_queue is constructed with a vector of integers, index_array, sized to the initial size of the implicit graph (1 vertex in my case). Unfortunately, this vector is never resized, so calls to mutable_queue::push wind up walking off the end of the index_array vector as the graph gets expanded (by my astar_visitor::examine_vertex callback), with various undefined (but generally bad) side-effects. So, after some mucking around, I've wound up with a solution to this where I specialize mutable_queue for my graph's vertex type, leaving astar_search and the standard mutable_queue definitions alone. The specialization is basically a copy of mutable_queue.hpp, with a change to the push method to ensure that index_array is sized correctly before indexing into it. Problem solved, everything working like a charm. Now, is this a bug in mutable_queue? Reading the two-paragraph description in mutable_queue.hpp, I'd guess this is how it is supposed to act. This would mean that implicit search with astar_search (and presumably any other search) isn't supported, because the queue that it uses for partial results can't get bigger as the graph itself grows. The documentation probably shouldn't mention implicit search if this is the case, or maybe there is need for a non-const version of astar_search that can use a more appropriate queue type... My solution, though it seems to work fine, is a bit of a bodge... As a side-note, I initially thought that the memory corruption that I was seeing was a result of vertex iterators becoming invalidated as the graph was expanded. I attempted a switch over to using listS for the VertexList parameter of the adjacency_list template (from vecS), but this causes all sorts of compiler errors under gcc 4.1.2. I tried making a similar change to the astar_search example program (astar-cities.cpp) and this too fails to compile (with 1.33.1 and 1.34.1). Shouldn't listS and vecS for the VertexList parameter be interchangeable? Cheers, Oliver

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Installed library names
by Yang Zhang 21 Apr '08

21 Apr '08

Hi, I'm working with a project whose build system passes -lboost_serialization as a flag to gcc. As far as I can tell from the configure options and from the Getting Started documentation, boost's installer only ever uses fully qualified names (libboost_serialization-gcc41-mt-1_35.so.1.35.0 on my system). Could the installer have possibly provided a libboost_serialization.so as well? Or did the authors of the project I'm trying to build probably manually create symlinks (or have their package manager create these) and assume that I would have the same? Thanks!

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Re: [Boost-users] [multi_index] custom template class for handle multi_index map
by damny＠web.de 21 Apr '08

21 Apr '08

hi joaquin, you are a genius :o) the absent default copy ctor and assignment operator were the reason for my problem ... can't see the wood for the trees. thank you daniel _________________________________________________________________________ In 5 Schritten zur eigenen Homepage. Jetzt Domain sichern und gestalten! Nur 3,99 EUR/Monat! http://www.maildomain.web.de/?mc=021114

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Mingw cross compilation
by James Choa 21 Apr '08

21 Apr '08

Hello everyone, Is there anyway for me to create a cross compilation version of the boost libraries? I have already compiled the linux version of the boost libraries and now I would like to compile a windows version of it. I'm using Fedora 8 with i386-mingw32 as my cross compiler (gcc 4.2.1). Any help would be greatly appreciated :) --James Choa

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Re: [Boost-users] [multi_index] how to check if an iterator ist still valid
by joaquin＠tid.es 21 Apr '08

21 Apr '08

Kowalke Oliver (QD IT PA AS) escribió: > Hi, > how can I ensure that an iterator is still valid (item was not > removed from the index)? > Well, there is no legal way to determine whether an iterator is valid or not unless you already have this information from other sources (the state your program is in or other contextual info). The reason is that if you've got an invalid iterator you cannot do anything with it except assign it a new valid value: iterator it=cont.find(...); cont.erase(it); // "it" is now invalid *it; // ILLEGAL ++it; --it; // ILLEGAL it2=it; // ILLEGAL foo(it); // ILLEGAL, provided foo accepts "it" by value it=cont.find(...); // OK [That said, you can grossly abuse the functionality provided by Boost.MultiIndex's safe mode (http://www.boost.org/doc/libs/1_35_0/libs/multi_index/doc/tutorial/debug.ht… ) to check whether an iterator is valid, but this is totally non-recommendable as safe mode is a debugging aid and not program-level functionality, you really oughtn’t do it.] Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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Facing problem while running sample code for filesystem
by Ashish Agrawal 21 Apr '08

21 Apr '08

Hi Users, I am very new user of Boost libraries. I am facing a problem while I am running a sample code of filesystem. My system is MAC OS X 10.4.11. I am executing following command for the attached .cpp file: c++ -I/usr/local/include/boost-1_35 test.cpp -o test \ /usr/local/lib/libboost_filesystem-mt-1_35.dylib I am getting following errors: /usr/bin/ld: warning can't open dynamic library: libboost_system-mt-1_35.dylib referenced from: /usr/local/lib/libboost_filesystem-mt-1_35.dylib (checking for undefined symbols may be affected) (No such file or directory, errno = 2) /usr/bin/ld: Undefined symbols: boost::system::get_posix_category() boost::system::get_system_category() boost::system::get_posix_category() referenced from libboost expected to be defined in libboost_system-mt-1_35.dylib boost::system::get_system_category() referenced from libboost expected to be defined in libboost_system-mt-1_35.dylib collect2: ld returned 1 exit status Thanks a lot in advance. -- Ashish Kumar Agrawal +41-76-358-5982

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boost::serialization - duplicate symbol from portable_binary_*archive
by j.c. 21 Apr '08

21 Apr '08

If you include the file "portable_binary_iarchive.hpp" or "portable_binary_oarchive.hpp" in a common header the result is: ld: duplicate symbol boost ::archive ::detail ::archive_pointer_iserializer < portable_binary_iarchive >::find(boost::serialization::extended_type_info const&)in /Users/jo/ Documents/packet_serialization_test/build/ orchid_packet_serialization.build/Debug/ packet_serialization_test.build/Objects-normal/i386/packet_base.o and / Users/jo/Documents/packet_serialization_test/build/ orchid_packet_serialization.build/Debug/ packet_serialization_test.build/Objects-normal/i386/main.o

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[multi_index] how to check if an iterator ist still valid
by Kowalke Oliver (QD IT PA AS) 21 Apr '08

21 Apr '08

Hi, how can I ensure that an iterator is still valid (item was not removed from the index)? regards,Oliver

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