June 2006 - Boost-users - lists.boost.org

boost::iostreams' zlib and writing multiple files
by Sascha Friedmann 14 Jun '06

14 Jun '06

Hello, how can I write/create an archive (gzlip or zlib) that contains multiple files. At the moment I can create only an archive which contains a file (named like the archive but ommitted the file-type) that contains my output. But what I need is to create an archive which contains multiple files. Is this even possible with the boost::iostreams framework? thanks Sascha

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[installer] No test libraries?
by Johan Nilsson 14 Jun '06

14 Jun '06

Hi, is there any specific reason as for why the Boost.Test libraries aren't available for download in the installer? // Johan

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Re: [Boost-users] Boost.Thread locking across two functions
by Moshe Matitya 14 Jun '06

14 Jun '06

On Fri, 09 Jun 2006 22:51:48 -0300, Peteris Krumins [Newsgroups] <pknewsgroups_at_[hidden]> wrote: > > Hello! > > I am using a library which itself internally does not use any thread > sync mechanisms but it provides callback functions > lib_lock() and lib_unlock() which I can specify if the lib is used in > multithread environment. > lib_lock() would get called before critical segment and after it > lib_unlock() would get called. > > I read Boost.Thread documentation and I understand that lock concept is > not thread-safe itself and should be used only at block scope. > This makes me think that I have no way to use locking provided by Boost > to acquire a lock in > lib_lock() function and release it in lib_unlock()? But I am not sure. > > Do you have any suggestions if this can be done using Boost? > > Thanks! > P.Krumins I don't think it was intended to be used this way, but you can accomplish what you want with the lock_ops<> class: mutex m; lib_lock() { boost::detail::thread::lock_ops<boost::mutex>::lock (m); } lib_unlock() { boost::detail::thread::lock_ops<boost::mutex>::unlock (m); } Moshe

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[test] Output log file name
by Johan Nilsson 14 Jun '06

14 Jun '06

Hi, I'm using the Boost.Test (unit test framework) from cvs, trying to get xml output redirected into files. The xml format itself is not a problem, but I can't find any options to get the output into files. Is this possible to do using either command-line arguments or environment variables? It's possible, but awkard, to use unit_test_log::set_stream, but I figured I'd check if there were any options before implementing that. / Johan

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n3wb question: Compiling boost::python "hello world" demo
by Salim Fadhley 13 Jun '06

13 Jun '06

I'm an experienced python developer, but unfortunately a ten-years out of practice C++ developer. For a future project I was hoping to play with Boost.python as a means of speeding up some calculations that were very tedious in python. For starters I wanted to get the "hello.cpp" demo compiling, but I am failing almost at step one. For starters in this file I am supposed to set the BOOST_ROOT: http://www.boost.org/libs/python/example/tutorial/Jamrules However I am not 100% sure that the operating system (Gentoo Linux) even installed the files in the right area. Is there a particular file that is allways going to be in the "BOOST ROOT", that way I will know for certain what to run. Next I am supposed to set up some environment variables. The instructions provided are for Windows only and say: " Make sure that the environment is set so that we can invoke the C++ compiler. With MSVC, that would mean running the Vcvars32.bat batch file. For instance:" Is there a Linux equivalent? Next I am told to use "bjam" to do the actual build. The instructions are once again very windows-centric: "bjam -sTOOLS=vc-7_1" What might be the corresponding syntax for users of GNU C++? Thanks! Sal

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type_with_alignment<5> ?
by Gottlob Frege 13 Jun '06

13 Jun '06

I'd like type_with_alignment<> to handle sizes between 'true' alignments, and/or have a way to map 'in bwetween' alignments to their lower alignment. ie I have a struct of unknown type, but known size = 5. What is it's alignment? You could 'punt' and say max_align, but I suggest that its alignment is <= 5 (ie probably 4 for a typical platform). ie imagine that the struct might have an int as it's first member, but can't have a double (assuming sizeof(double) > 5), so the alignment might need to be alignment_of<int>, but can't be alignment_of<double>. Does this assumption hold true? So how can I map (at compile time) an integer 'n' to the closest 'x' <= n where x is from the set S, and where S is the set of possible alignments? Tony

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Re: [Boost-users] [boost.multi_array] Best use of memory
by Ronald Garcia 13 Jun '06

13 Jun '06

Hello Sebastien, Ideally, you should be able to work with an array of doubles, rather than an array of pointers to double. I can create an multi_array with the dimensions you mention. To answer your questions, multi_array uses a standard library allocator to allocate a contiguous block of memory in which to hold the array data. I'm afraid I do not know why you cannot exceed these limits. ron > I'm currently using multi_array to represent 3D matrices of doubles, I > was wondering which would be the best use since the array has to > hold a > very large amount of data. I' currently testing whith a multi_array of > 800x800x100 to hold double or pointers to double and I have memory > problems. When I declare the multi_array whith pointers to doubles > I can > usually go up to 775x775x100 without problems but when I try the same > thing with a multi_array of doubles I get a bad alloc error. My real > needs for the moment are for a multi_array of 800x600x57 but I will > need > bigger storage capacity in the near future, what are your sugesstions. > Is the multi_array a pointer itself? > How is memory management handled? > How can go beyond these limits? > > > > -- > Sébastien Fortier

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[Tokenizer] Separate by multiple characters?
by Stian Karlsen 13 Jun '06

13 Jun '06

Hi. Can the Boost Tokenizer be used to split a string with a delimiter of several characters? With this I mean that the delimiter ";;" would split ("12;3;;45") into ("12;3","45"). I can't find functions etc for this in the documentation and the examples. Is there any other class that does this easily? Best Regards, Stian

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how to turn on multiline option of boost::regex_search() algorithm
by Renjie Zhao 13 Jun '06

13 Jun '06

Can any one tell me how to specify "Multiline" search while using regex? e.g. std::string fb; // fb stores a fragment of html code, multiline; boost::regex pattern("</tr>\r\n</table>\r\n</td>\r\n</tr>\r\n</table>\r\n</td>\r\n</tr>\r\n</table>"); boost::smatch res; boost::match_flag_type flags = boost::match_default; std::string::const_iterator s , e; s = fb.begin(); e = fb.end(); if(boost::regex_search(s, e, res, pattern, flags)) { //process the match. } else { //I am always here } When I use some other regex tools to check the same target string and match pattern string, I always get the right thing as expected. How can I alter the option of boost::regex_search to satisfy the original request? thanks -- This is my Very Signature. Ha, pretty good?

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Link options(TO DALE MCCOY)
by umut tabak 13 Jun '06

13 Jun '06

Dear, Sorry for replying to a specific person since the reply link is not operational for me(at least). g++ -c -I/usr/local/include/boost-1_33_1 filename.cc -c option only creates the linkable object file(correct me if I am mistaken so you have link some libraries to get the proper exe file(I am under XP now)) but -c option does not call the linker. I have chosen both boost and boost devel packages for install under Cygwin. I was using the same code under linux with the following link options g++ -g -o filename filename.cc -I/usr/local/opt/boost_1_33_1/include/boost-1_33_1/ -L/usr/local/opt/boost-1_33_1/lib -lboost_filesystem-gcc So I was linking to the boost_filesystem-gcc library. I tried the same but it gave errors, Regards,

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