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RE: [Boost-users] Re: MPL Question on crossing the compile \ runtimebarrier with bind | adding to boost profiler abstracted file access
by Brian Braatz 31 Mar '05

31 Mar '05

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org [mailto:boost-users- > > "Brian Braatz" <brianb(a)rmtg.com> writes: > > > I can always pass in a functor, but what I really want for Christmas is > > to be able to > > > > Tyepdef MyClass<std::ofstream, > > bind(&std::ofstream::open,_1,"MyFile.txt") > MyNewClass; > > > > This doesn't work because bind returns an actual OBJECT instead of a > > type. (intuitively - it would be cool if I could say > > bind(...)::Type which would give me the TYPE of the generated > > functor) > > > > SO that led me to be up until 3 am reading about mpl::lambda. I am still > > trying to determine if THAT can be used in place, but the dots are not > > connecting for me yet. > > > > Any suggestions or directions pointed GREATLY appreciated. > [Dave Abrahams Writes:] > You want "typeof," a mythical operator not yet in the C++ language -- > but many implementations support some form of it as an extension. > There's a prototype typeof library in the Sandbox files area now, by > Arkadiy Vertleyb and others. Check it out. I suggest you browse the > recent thread on typeof in boost-devel as well. [Brian Braatz Writes:] As always THANK YOU Dave What about the boost\Lambda.bind vs MPL bind?. Is there a way to write the Tyepdef MyClass<std::ofstream,bind(&std::ofstream::open,_1,"MyFile.txt") MyNewClass; As a MPL driven expression, or is the "typeof" the only option (I am ignoring the hand coded functor option). (I am asking partially because I am having a hard time "seeing" the difference between the MPL lambda and the boost lambda- I will keep re-reading the MPL book... :) ) (also don't get me wrong, the typeof looks very cool- I am just trying to connect the dots) ALSO I REALLY WISH I could pass strings to templates, maybe if I am lucky Santa will join the C++ committee....... Thanks again Brian

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Link error Boost.Serialization
by Christian Heinemann 31 Mar '05

31 Mar '05

Hi, i want to use serialization library from boost. I'm enthused about the functionality. But when i try to compile and link the first example (which can be find on http://www.boost.org/libs/serialization/doc/index.html) i get the following error messages: (with g++ -o serialize serialize.cpp -lboost_serialization-gcc -I/usr/local/include/boost-1_32) "/usr/local/lib/gcc/x86_64-unknown-linux-gnu/3.4.3/../../../libboost_serialization-gcc.a(basic_iarchive.o)(.text+0x1ef): Infunction `boost::archive::detail::basic_iarchive::~basic_iarchive()': : undefined reference to `std::__default_alloc_template::_S_force_new' /usr/local/lib/gcc/x86_64-unknown-linux-gnu/3.4.3/../../../libboost_serialization-gcc.a(basic_iarchive.o)(.text+0x254): Infunction `boost::archive::detail::basic_iarchive::~basic_iarchive()': : undefined reference to `std::__default_alloc_template::_S_force_new' /usr/local/lib/gcc/x86_64-unknown-linux-gnu/3.4.3/../../../libboost_serialization-gcc.a(basic_iarchive.o)(.text+0x279): Infunction `boost::archive::detail::basic_iarchive::~basic_iarchive()': .... (~ 10 Pages) " And with "g++ -o serialize serialize.cpp -lboost_serialization-gcc -I/usr/local/include/boost-1_32 -lboost_thread-gcc-mt" only: "`.gnu.linkonce.t._ZNK5boost7archive17archive_exception4whatEv' referenced in section `.rodata' of /usr/local/lib/gcc/x86_64-unknown-linux-gnu/3.4.3/../../../libboost_serialization-gcc.a(basic_iarchive.o): defined in discarded section `.gnu.linkonce.t._ZNK5boost7archive17archive_exception4whatEv' of /usr/local/lib/gcc/x86_64-unknown-linux-gnu/3.4.3/../../../libboost_serialization-gcc.a(basic_iarchive.o) " I use Boost at first time and i'm going to despair.. Maybe it is important: i have installed Boost with gcc 3.4.3 on SuSE 9.2 (x86_64). With gcc 3.3.4 similar error message occur (g++ -o serialize serialize.cpp -lboost_serialization-gcc -I/usr/local/include/boost-1_32 ): "`.gnu.linkonce.t._ZNK5boost7archive17archive_exception4whatEv' referenced in section `.rodata' of /usr/local/lib/libboost_serialization-gcc.a(basic_iarchive.o): defined in discarded section `.gnu.linkonce.t._ZNK5boost7archive17archive_exception4whatEv' of /usr/local/lib/libboost_serialization-gcc.a(basic_iarchive.o) " Thank you for help! Christian _________________________________________________________________________ Mit der Grupppen-SMS von WEB.DE FreeMail können Sie eine SMS an alle Freunde gleichzeitig schicken: http://freemail.web.de/features/?mc=021179

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Errors Compiling exception
by Eyal Inbar 31 Mar '05

31 Mar '05

I'm trying to use dijkstra-example and i get /usr/local/include/boost/graph/dijkstra_shortest_paths.hpp:137: exception handling disabled, use -fexceptions to enable I'm not sure what version i have but i have the folder /i386-glibc21-linux if its help? eyal

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MPL Question on crossing the compile \ runtime barrier with bind | adding to boost profiler abstracted file access
by Brian Braatz 30 Mar '05

30 Mar '05

I have been reading (ahem and re-reading) "C++ Template Metaprogramming" I have a problem I am trying to solve and was up late last night looking for the answer to jump out at me. If nothing else this helps me as I tend to re-read the same chapters over and over. Here is what I am trying to do In working on coded I am adding to the proposed Boost Profiler (started by Chris Diggings, inherited by yours truly). I am using RAII all "over" my program in the extensions I am adding to the profiler. This puts me in a spot where I have MACROs which stuff the profile points in the program. Now the problem is I would like to be able to add a template param to the TYPE of the profile points which gives it the initialization code for the STREAM it is using. The problem is since the objects themselves get created ALL OVER the program, I don't have a single point of construction (because I am using RAII to track the life cycles inside the functions themselves). I.e. I want to be able to use Boost.IOstreams or ofstream or whatever for these objects.I just need to , at the TYPE DEFINITION be able to define how to initialize this passed stream. I need to be able to do something like this Template <typename STREAMTYPE, typename INITFUNCTOR> Class MyClass { Public: STREAMTYPE outstream; MyClass() { INITFUNCTOR f(outstream); // open the file, init iostreams , or whatever } }; I can always pass in a functor, but what I really want for Christmas is to be able to Tyepdef MyClass<std::ofstream, bind(&std::ofstream::open,_1,"MyFile.txt") > MyNewClass; This doesn't work because bind returns an actual OBJECT instead of a type. (intuitively - it would be cool if I could say bind(...)::Type which would give me the TYPE of the generated functor) SO that led me to be up until 3 am reading about mpl::lambda. I am still trying to determine if THAT can be used in place, but the dots are not connecting for me yet. Any suggestions or directions pointed GREATLY appreciated. Is there a way to make this work with MPL::Lambda? Thanks Brian

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RE: [Boost-users] Boost.lambda
by Brian Braatz 30 Mar '05

30 Mar '05

Ah Kindred spirits. I asked a similar question awhile ago (like last year). I am sorry I was not able to find the original message. The answer I was given was that the & is the correct syntax per the CPP standard. What you are doing is taking the address of a memberfunction. What was confusing to me was that some compilers allow you to LEAVE OFF the & while others don't. The ones that do are trying to be helpful but are not conformant. ________________________________ From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Sean DeNigris Sent: Tuesday, March 29, 2005 7:31 PM To: boost-users(a)lists.boost.org Subject: [Boost-users] Boost.lambda Can anyone explain why the class member functions need their address taken when used in a boost::lambda::bind inside the class? e.g. vector<int> v; MyClass theClass; for_each(v.begin(), v.end(), bind(MyClass::DoSomething, &theClass, _1)); //The above compiles fine, but... class MyClass { public: void DoSomething(const int& i) { ... } void Go() { for_each(myInts.begin(), myInts.end(), /*--------------------->*/ bind(MyClass::DoSomething, this, _1)); } vector<int> myInts; }; The above code does not compile. The marked line needs to be: bind(&MyClass::DoSomething, this, _1)); Why? Thanks. - Sean

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Re: size of libboost_thread-gcc-mt.so
by Vladimir Prus 30 Mar '05

30 Mar '05

Amerio wrote: >>>> After compiling libboost_thread-gcc-mt.so on debian/gcc-2.95.4, >>>> this so weights 195kB > [...] >> Without read_write_mutex the size of gcc/release/shared build is 46K. >> With read_write_mutex the size is 136K. >> >> Wow, that's a difference! >> >> When I comment out explicit template instantiations in that source >> file, the library is becomes 76K. The comment says explicit >> instantination are needed to detect syntax errors in templates but >> those instantination bloat the library. > > Would there be any problem if I comment out the explicit instantations in > this file for production code ? > Are they in there *only* for syntax checking ??? I think that's the case. Adding #ifndef NDEBUG might be a reasonable solution. Note that if you use all of mutex types, you'll still get the code size penalty, but most likely you won't use all of them. > In this case, what about commiting a new rev in the cvs without this ? That's up to Boost.Thread maintainers. > Note : In my case, 100kB wasted is large enough to be an issue (running > low on free space, embedded system) I understand. - Volodya

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size of libboost_thread-gcc-mt.so
by Amerio 30 Mar '05

30 Mar '05

Hello, After compiling libboost_thread-gcc-mt.so on debian/gcc-2.95.4, this so weights 195kB, while libpthread weights only 100kB. Why such a huge difference ? Isn't boost::thread meant to be as lightweight as possible ? What about the raw inpact on runtime memory consumption compared to std pthreads ?

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Mailing list archive change and list downtime
by Beman Dawes 30 Mar '05

30 Mar '05

DongInn Kim, Jeff Squyres, and the other sysadmins at Indiana University are planning to switch all the Boost mailing list archives they host from MHonArc to Hypermail. They report "Hypermail seems to be much more stable, faster, and more efficient than MHonArc. We've been quite pleased with it, and have deployed it across most other lists on the listserver already (the boost lists were saved until last)." The old archives will still be available, and DongInn and Jeff have made various plans to minimize disruptions. All the listservers will be down during the transition, which is planned to start at 11 PM Saturday night (Eastern US time). Thanks to all the folks at IU for their help with Boost list hosting, --Beman

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Errors Compiling date_time Serialization Headers w/ Gcc on Linux
by Jalon, Arnon 30 Mar '05

30 Mar '05

Hi, I am new to the list. Appologies in advance if I'm posting something that's been already addressed, but I was unable to find anything related to it while searching the archives. I'm trying to use the date_time serialization headers in my application. I'm actually using the boost headers and libraries that came with the fedora core 3 linux distribution, and compiling with gcc 3.4.2. Including boost/date_time/time_serialize.hpp in my source gives me several compilation errors. I perused the time_serialize.hpp and greg_serialize.hpp headers and found places where the typename keyword was being used in front of class types that were simply qualified by namespace, as well functions where variables were used that weren't declared. I modified the headers to get it to compile, but would like to see if anyone else has been able to work around the problem in a less intrusive way? If need be I can post the patch files I created to a proper place. Below are the errors I was getting: g++ -g -I. -c parseAccessLog.cpp In file included from /usr/include/boost/date_time/posix_time/time_serialize.hpp :13, from logobject.hpp:11, from parseAccessLog.cpp:19: /usr/include/boost/date_time/gregorian/greg_serialize.hpp: In function `void boost::serialization::save(Archive&, const boost::gregorian::date_period&, unsigned int)': /usr/include/boost/date_time/gregorian/greg_serialize.hpp:150: error: no class template named `date' in `boost::gregorian' /usr/include/boost/date_time/gregorian/greg_serialize.hpp:150: error: invalid type in declaration before '=' token . . Repeated several times for similar condition through out greg_serialize.hpp . . /usr/include/boost/date_time/gregorian/greg_serialize.hpp: In function `void boost::serialization::load_construct_data(Archive&, boost::gregorian::nth_kday_of_month*, unsigned int)': /usr/include/boost/date_time/gregorian/greg_serialize.hpp:336: error: `pd' undeclared (first use this function) /usr/include/boost/date_time/gregorian/greg_serialize.hpp:336: error: (Each undeclared identifier is reported only once for each function it appears in.) . . Also repeated several times for similar condition . . In file included from logobject.hpp:11, from parseAccessLog.cpp:19: /usr/include/boost/date_time/posix_time/time_serialize.hpp: In function `void boost::serialization::save(Archive&, const boost::posix_time::time_period&, unsigned int)': /usr/include/boost/date_time/posix_time/time_serialize.hpp:131: error: no class template named `ptime' in `boost::posix_time' /usr/include/boost/date_time/posix_time/time_serialize.hpp:131: error: invalid type in declaration before '(' token . .

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Boost.lambda
by Sean DeNigris 30 Mar '05

30 Mar '05

Can anyone explain why the class member functions need their address taken when used in a boost::lambda::bind inside the class? e.g. vector<int> v; MyClass theClass; for_each(v.begin(), v.end(), bind(MyClass::DoSomething, &theClass, _1)); //The above compiles fine, but. class MyClass { public: void DoSomething(const int& i) { . } void Go() { for_each(myInts.begin(), myInts.end(), /*--------------------->*/ bind(MyClass::DoSomething, this, _1)); } vector<int> myInts; }; The above code does not compile. The marked line needs to be: bind(&MyClass::DoSomething, this, _1)); Why? Thanks. - Sean

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