- Boost-users - lists.boost.org

Re: Iterator adaptor interoperability
by Kris Braun 28 Feb '04

28 Feb '04

Dave Abrahams wrote: > Your best bet is to write an type generator: > template <class Iterator> > struct simple_iterator > { > typedef boost::transform_iterator< > do_nothing< typename Iterator::value_type > > , Iterator > > type; > }; Thank you for the quick and clear reply! I'm now having a very similar problem with a slightly more complicated example (that builds on the first): template< class Iterator > struct harder_iterator { typedef simple_iterator< Iterator >::type inner_type; typedef boost::indirect_iterator< inner_type > type; static type Create( const Iterator& iter ) { return type( inner_type( iter ) ); } }; This "composite" iterator not only has problems with comparison, but assignment from non-const to const as well. Is there a way to handle this case? Thanks, Kris __________________________________ Do you Yahoo!? Yahoo! Mail SpamGuard - Read only the mail you want. http://antispam.yahoo.com/tools

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building boost 1.31.0
by Greg Silverman 27 Feb '04

27 Feb '04

Hi, I have not been able to build version 1.31.0. I run bjam -sTOOLS=gcc-nocygwin Basically, I get a lot of undefined references from the linker. The linker cannot find "cpp_main", "init_unit_test_suite", and, so on. It seems to be a problem with the testing, regression testing, unit testing, etc. Greg Silverman Northrop Grumman San Jose, CA

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lambda / boost usage questions
by Luis De la Parra 26 Feb '04

26 Feb '04

hello, I don't have much experience with boost, so I'm having problems getting boost lambda to work...hope someone here can point me in the right direction. I have: class Song {public: string artist( ) const { return m_artist } string title( ) const { return m_title } private: string m_artist, m_title; } typedef boost::shared_ptr<Song> pSong; vector<pSong> c; and I am trying to use lambda to find a song in c which matches a certain artist and title...something like iterator it = find_if( c.begin(), c.end(), something ) but I havn't figured out what "something" should look like I've tried find_if(begin(),end(), (_1->artist() == "a1" && _1->title = "t1" ) ); but the compiler -- or I =) -- doesn't seem to know the type of _1 --> error: base operand of `->' has non-pointer type `const boost::lambda::lambda_functor<boost::lambda::placeholder<1> >' If I try it = find_if(begin(),end(), boost::bind(&Song::artist,_1) == "a1" ); it fails because "_1" is ambiguos (defined as lambda/placeholder and boost/arg ) using boost::lambda::bind (and not including the "normal" bind ) gives a bunch cryptic errors... I've tried several other variants with lambda / lambda::bind / boost::bind but I havn't figured it out... can anyone help me out? I'd also like to know what's the difference between boost::bind and boost::lambda::bind ? Also... is there a way to know when a lambda object is going to be constructed?, it's probably just that I don't know much about the BLL, but in cases where you have several nested lambdas and binds, I'm not sure which lambda objects will get constructed. regards, luis

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bug in numeric_cast<unsigned long>, <unsigned char>, and <unsigne d int> in gcc 3.3.2
by King, William D 26 Feb '04

26 Feb '04

Hello, I am seeing a bug that the regression tests miss for numeric_cast<unsigned long> with gcc 3.3.2. Specifically, the following code is throwing an exception: double small_value = 1.25; unsigned long l=0; l = numeric_cast<unsigned long>(small_value); // throws exception! unsinged char c=0; c = numeric_cast<unsigned char>(small_value); // throws exception! I am under the impression that numeric_cast is supposed to accept losses of precision (by truncating the fractional values), and to throw exceptions only if there is a range or sign error. Is this so? This error happens only when I try to cast a value with a non-zero fraction; i.e. 1.25 breaks but 1.0 is fine. It only occurs for unsigned types -- signed int, char, and long appear to work correctly. I have found the same incorrect behavior with gcc 3.3.2 on both solaris and linux. Using sunpro on solaris, the same code runs correctly. The regression tests don't catch this, since they only test numeric_cast with integral values 1 and LONG_MAX. Any ideas? It looks like a compiler problem to me. Davis King william.d.king(a)bankofamerica.com

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Boost.Test and Threads
by p.klotz＠icoserve.com 26 Feb '04

26 Feb '04

Hi After our migration from Boost 1.30.2 to Boost 1.31.0 several multithreaded tests no longer work stable. We tracked it down to the macros BOOST_UT_LOG_BEGIN and BOOST_UT_LOG_END. When one protects this macro calls with a mutex, the tests work stable again. After the investigation we found 'Support for the testing of multithreaded programs.' on the open issues list of Boost.Test. Does this mean that Boost.Test is not thread-safe at all? Do we misuse Boost.Test by calling things like BOOST_CHECK_EQUAL, BOOST_CHECK and BOOST_REQUIRE concurrently from different threads? Any clarification on this topic is welcome. Best regards, Peter.

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newbie doubts in compilation process
by Gustavo Sánchez 26 Feb '04

26 Feb '04

Hi all, I am newbie in Boost libraries, and I'm specially interested in Graph Library (BGL). I'm working with VC++ 6.0 and I have a couple of questions about usign the library under this SDK. Of course I've read the Boost documentation and I know VC++ 6 doesn't pass the regresion test but I'm doubty about the compilation process. Those are the steps I followed: 1.- I did the outlined comands in getting started cd boost_1_31_0 bjam "-sTOOLS=msvc" install As result I obtained in drive C: a boost dir with "include" and "libs" subdirs and boost_date_time-vc6-mt-1_31.dll boost_date_time-vc6-mt-gd-1_31.dll boost_filesystem-vc6-mt-1_31.dll boost_filesystem-vc6-mt-gd-1_31.dll boost_regex-vc6-mt-1_31.dll boost_regex-vc6-mt-gd-1_31.dll boost_signals-vc6-mt-1_31.dll boost_signals-vc6-mt-gd-1_31.dll boost_thread-vc6-mt-gd-1_31.dll and the related .lib files. Why aren't there any .dll file of the others libraries(graph, math, type_traits...)??? 2.- I executed bjam in directory: BOOST_ROOT\libs\graph\test and what I obtained was empty directories like BOOST_ROOT\bin\boost\libs\graph\test\vector_graph_cc.test\msvc\debug just one for every test source. I supose that is due to VC++ 6.0 is not able to compile the BGL, is that the reason??? I get something similar if I executed bjam in directory: BOOST_ROOT\libs\graph\examples 3. I did that ---> A full set of tests and status tables can be run thusly on a Windows system: cd %BOOST_ROOT%\status bjam --dump-tests test >bjam.log 2>&1 start notepad bjam.log (this is just a cut of the full file ilustrating the output related to graph library) boost-test(COMPILE) "property_iter" : "libs\graph\test\property_iter.cpp" boost-test(COMPILE) "copy" : "libs\graph\test\copy.cpp" boost-test(COMPILE) "vector_graph_cc" : "libs\graph\test\vector_graph_cc.cpp" boost-test(RUN) "isomorphism" : "libs\graph\test\isomorphism.cpp" boost-test(RUN) "subgraph" : "libs\graph\test\subgraph.cpp" boost-test(COMPILE) "reverse_graph_cc" : "libs\graph\test\reverse_graph_cc.cpp" boost-test(COMPILE) "graph_concepts" : "libs\graph\test\graph_concepts.cpp" boost-test(RUN) "graph" : "libs\graph\test\graph.cpp" boost-test(COMPILE) "filtered_graph_cc" : "libs\graph\test\filtered_graph_cc.cpp" boost-test(COMPILE) "edge_list_cc" : "libs\graph\test\edge_list_cc.cpp" boost-test(COMPILE) "dijkstra_cc" : "libs\graph\test\dijkstra_cc.cpp" boost-test(COMPILE) "dfs_cc" : "libs\graph\test\dfs_cc.cpp" boost-test(RUN) "dfs" : "libs\graph\test\dfs.cpp" boost-test(COMPILE) "bfs_cc" : "libs\graph\test\bfs_cc.cpp" boost-test(RUN) "bfs" : "libs\graph\test\bfs.cpp" boost-test(COMPILE) "adj_matrix_cc" : "libs\graph\test\adj_matrix_cc.cpp" boost-test(COMPILE) "adj_list_cc" : "libs\graph\test\adj_list_cc.cpp" boost-test(RUN) "transitive_closure_test" : "libs\graph\test\transitive_closure_test.cpp" What is quite surprising to me because it's suposed VC++ can't compile all BGL, http://boost.sourceforge.net/regression-logs/cs-win32.html. Some explanation about this ??? Thanks a lot ...(I continue diving in ) --------------------------------- Antivirus Filtros antispam 6 MB gratis ¿Todavía no tienes un correo inteligente?

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boost::lambda and MinGW on Windows
by Vladimir Suhoy 26 Feb '04

26 Feb '04

I have troubles compiling boost::lambda with MinGW on windows MinGW: 2.0.0-3 (yeah, I know its old) gcc: 3.2 (mingw special 20020817-1) The compiler thinks that types in boost/lambda/construct.hpp in boost::detail::destructor are undefined.. However when I put #include <boost/type_traits/remove_cv.hpp> #include <boost/type_traits/is_pointer.hpp> lines in boost/lambda/construct.hpp - then it works. _________________________________________________________________ Add photos to your messages with MSN 8. Get 2 months FREE*. http://join.msn.com/?page=features/featuredemail

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RE: [Boost-users] newbie doubts in compilation process
by Ben Hutchings 26 Feb '04

26 Feb '04

Gustavo Sánchez <gustsanc(a)yahoo.es> wrote: [snip] 1.- I did the outlined comands in getting started cd boost_1_31_0 bjam "-sTOOLS=msvc" install As result I obtained in drive C: a boost dir with "include" and "libs" subdirs and [snip list of DLLs] and the related .lib files. Why aren't there any .dll file of the others libraries(graph, math, type_traits...)??? All their source code is included in header files as inline functions or function templates. Whatever code you use from them will automatically be compiled into your executable. I can't answer your other questions. Ben.

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RE: [Boost-users] Re: about license
by Ben Hutchings 26 Feb '04

26 Feb '04

Darryl Green <Darryl.Green(a)unitab.com.au> wrote: > Cross posted from boost-users... > > > -----Original Message----- > > From: David Abrahams [mailto:dave@boost-consulting.com] > > Sent: Wednesday, 25 February 2004 11:43 AM > > Marleny Rafferty <marleny(a)rafferty.net> writes: > > > > > Hi- > > > > > > I am considering using boost in my applications, but I have a > > > question about the boost license at > > > http://www.boost.org/LICENSE_1_0.txt . It says (edited) > > > "Permission is hereby granted, free of charge, to ... use [and] > > > reproduce ... the Software". > > > > > > It also says that any derivative works must also have the same > > > license grant. > > > > > > If my application uses boost libraries unchanged, is it > > > considered a derivative work? > > > > Yes. > > Really? The ligitimacy of this stance seems questionable (but ianal > etc). Further I did not see it as being part of the objectives for the > license. Quite the opposite in fact. (Disclaimer: IANAL, and any reputable lawyer would take plenty of time to provide you with considered advice.) My understanding is that executable or object code is a derivative work of all the source code that it is built from. So any executable that uses a library is a derivative work of that library. (There is a question as to whether this applies to header files that only define named constants and structure layouts, but little question that it applies to inline and statically-linked function definitions. The FSF asserts that using dynamically-linked function definitions also creates a derivative work.) Your source code, however, does not become a derivative work of a library that it depends on, unless you copy part or all of the library's source code into it.

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shared_ptr/shared_array Question
by voodoo4 26 Feb '04

26 Feb '04

I downloaded yesterday the boost libraries (mainly for the memory libs) and to tell the truth i'm impressed with pool and smart pointers. Especially the boost smart pointers will save me from months of coding! However i have a question about smart pointers. Let's say i have these objects(the code is just an example): class Slave { Slave(); ~Slave(); }; class Master { Master(); Master(int size); ~Master(); Slave *sl; }; I want "sl" to be an array of Slaves on the free store but the sized will be determined in the constructor. With normal pointers i would write: Master::Master(int val) { sl=new Slave[val]; } Master::~Master() { delete sl; } How can i achieve the same with boost smart pointers? I've read the manual three or four times but i still don't get how to work this out. Does this have something to do with the empty ptr? I believe solution is in front of my eyes but i'm too blind(as usual) to see it...

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