July 2009 - Boost-users - lists.preview.boost.org

[Signals2] Wrapper function for connecting slot won't compile
by Marc DelaCruz 07 Jul '09

07 Jul '09

I have code similar to the following: template<typename A> class SomeClass { void memFunc(FileDescBase&) { ... } }; template<typename B> class OtherClass { void setOpenCallBack(boost::signals2::signal<void (FileDescBase&) >::slot_type const& rOpenSlot) { mOpenSignal.connect(rOpenSlot); } void setCallBacks() { SomeClass myClass; setOpenCallBack(boost::bind(&SomeClass<B>::memFunc, &myClass)); //does not compile setOpenCallBack(boost::signals2::signal<void (FileDescBase&) >::slot_type(&SomeClass<B>::memFunc, &myClass)); //does not compile either } boost::signals2::signal<void (FileDescBase&) > mOpenSignal; }; Even a direct call to mOpenSignal.connect(boost::signals2::signal<void (FileDescBase&) >::slot_type(&SomeClass<B>::memFunc, &myClass)) does not comiple. Thanks.

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Boost ASIO - SO_LINGER Socket option is not working
by Nick Aschberger 07 Jul '09

07 Jul '09

Hi All, I have a situation where at termination of my program, I am closing my socket, and then deleting the socket object. Note, we are using non-asynchronous (blocking) accesses at this point, boost is version 1.36. In some cases, the socket has had some data written to it, but that data is never received by the connected client - because I destroy the socket before the data is sent. So, SO_LINGER is the socket option that is supposed to solve all my worries (it should wait on close for any unsent data to be sent), however I am using it and there is no effect. I presume because I'm doing something wrong. Here is my psuedo-code flow: /* Creation of socket */ m_socket = new boost::asio::ip::tcp::socket(m_io_service); /* Connect the socket with something like: */ acceptor.accept(*m_socket, error); /* Set SO_LINGER option on connected socket */ boost::asio::socket_base::linger linger_op(true, 2000); m_socket->set_option(linger_op); /* program executes, does some stuff */ /* At termination */ // close the socket m_socket->close(); delete(m_socket); I experimented with m_socket->shutdown() instead of close, and it made little difference. In fact, from the documentation it seems shutdown() is the one I definitely don't want to call, as close() is supposed to wait for data to be sent. If anyone has some suggestions as to what would be correct, I would much appreciate it. cheers Nick Aschberger

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STLport Support
by biolaser 06 Jul '09

06 Jul '09

Can anyone point me to a place to obtain support/technical answers (tech forum, etc) for STLport? The STLport forum at SourceForge appears to be largely abandoned. Thanks much! William Stroupe

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[pool] singlton_pool::malloc returning bad address
by Jonathan Leonard 06 Jul '09

06 Jul '09

Hi all, In a long running process on Windows, I'm seeing singleton_pool::malloc eventually return addresses such as 0x100f34b0 (which in this case [according to vmmap] is an address into a 'read-only' section (.rdata) of a DLL which was loaded for 'execute/copy on write'). The system [rightly] barfs at the request to write to that address. Anyone have an idea what could be going on here? Many thanks, Jonathan

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Licensing issues for boost users
by Avi Bahra 06 Jul '09

06 Jul '09

I am trying to understand the boost licensing in terms of users of boost. Is there any where I can find out additional information about this ? For the project I am working on, we will only ever* use* boost, are there an licensing issues/restrictions for *users* of boost ? Am I right is assuming that boost software license only applies to organization that contribute to boost, and not users? i.e I am assuming that users of boost do not need to embed the boost license in our own code that uses the boost libraries ? in essence we are free to license/copyright our own code in any manner, even though it uses boost? Any help in this matter would be greatly appreciated. Avi

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[Interprocess] Compilation errors for atomic operations.
by d s 06 Jul '09

06 Jul '09

I am using managed_shared_memory to implement a cache. However during compilation I get the following error - g++ -o .build/CacheLib/cachebase.pic.o -c -fPIC -m64 -g -isystem /usr/local/include/c++/3.4.2 -isystem /usr/local/include/c++/3.4.2/sparc-sun-solaris2.9 -isystem /usr/include -isystem /usr/local/include-isystem /usr/local/lib/gcc/sparc-sun-solaris2.9/3.4.2/include -isystem /usr/include/sys -nostdinc -nostdinc++ -I/usr/local/include/boost-1_39 -I/geneva1/apps/IRB_2.2.30/2.2.30_CURRENT/include -I/oracle/product/9.2.0/rdbms/demo -I.build/CacheLib -Isrc/CacheLib -I/usr/local/include/log4cpp src/CacheLib/cachebase.cpp In file included from /usr/local/include/boost-1_39/boost/interprocess/detail/managed_open_or_create_impl.hpp:20, from /usr/local/include/boost-1_39/boost/interprocess/managed_mapped_file.hpp:20, from src/CacheLib/cachebase.h:12, from src/CacheLib/cachebase.cpp:8: /usr/local/include/boost-1_39/boost/interprocess/detail/atomic.hpp: In function `boost::uint32_t boost::interprocess::detail::atomic_add32(volatile boost::uint32_t*, boost::uint32_t)': /usr/local/include/boost-1_39/boost/interprocess/detail/atomic.hpp:331: error: `atomic_add_32_nv' undeclared (first use this function) /usr/local/include/boost-1_39/boost/interprocess/detail/atomic.hpp:331: error: (Each undeclared identifier is reported only once for each function it appears in.) /usr/local/include/boost-1_39/boost/interprocess/detail/atomic.hpp: In function `boost::uint32_t boost::interprocess::detail::atomic_cas32(volatile boost::uint32_t*, boost::uint32_t, boost::uint32_t)': /usr/local/include/boost-1_39/boost/interprocess/detail/atomic.hpp:341: error: `atomic_cas_32' undeclared (first use this function) /usr/local/include/boost-1_39/boost/interprocess/detail/atomic.hpp: In function `boost::uint32_t boost::interprocess::detail::atomic_inc32(volatile boost::uint32_t*)': /usr/local/include/boost-1_39/boost/interprocess/detail/atomic.hpp:347: error: `atomic_add_32_nv' undeclared (first use this function) /usr/local/include/boost-1_39/boost/interprocess/detail/atomic.hpp: In function `boost::uint32_t boost::interprocess::detail::atomic_dec32(volatile boost::uint32_t*)': /usr/local/include/boost-1_39/boost/interprocess/detail/atomic.hpp:353: error: `atomic_add_32_nv' undeclared (first use this function) scons: *** [.build/CacheLib/cachebase.pic.o] Error 1 scons: building terminated because of errors. I am using gcc version 3.4.2 on solaris 9. Reading specs from /usr/local/lib/gcc/sparc-sun-solaris2.9/3.4.2/specs Configured with: ../configure --with-as=/usr/ccs/bin/as --with-ld=/usr/ccs/bin/ld --disable-nls Thread model: posix gcc version 3.4.2 Kindly advice what is the problem? Is there any way I can use pthread atomic operation instead to solaris atomic operations. Note: The same code is working fine on RHEL Enterprise 5 and Hp-UX.

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Using iostreams to serialize into and from a memory buffer
by Ivan Gonzalez 06 Jul '09

06 Jul '09

Dear all, I have some numerical data in my code that I'm saving to a file. My code loops thousands of times generating a set of this data in each loop step. The data is reused within the same step but there is no need to save it to the next one. Currently I'm using the serialization library to write all the data to a binary file (using the optimization for contiguous arrays) and then read it. I thought (maybe naively) I could increase performance keeping the data in memory instead of write/read to disk. I came across this post http://lists.boost.org/boost-users/2008/05/36235.php where how to serialize into/from a memory buffer using boost::iostreams is explained. However I found that using the solution in the post is way slower than write/read to disk. In fact modifying the code in the post to use std::ofstream and std::ifstream open with the std::ios::binary flag makes the code 5 times faster. Am I missing something or is it right that the iostream solution is slower ?. (I understand that sometimes you don't have the option to write to a file, but is this the fastest way to use a memory buffer ?) Thanks in advance, Ivan

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[Boost.Test] C++ Unit Tests With Boost.Test, Part 5
by legalize+jeeves＠mail.xmission.com 05 Jul '09

05 Jul '09

[Please do not mail me a copy of your followup] <http://legalizeadulthood.wordpress.com/2009/07/05/c-unit-tests-with-boost-t…> In Part 4 of this series, we completed some UI functionality using a test-driven development style. In this final part of the series, I will cover the facilities in Boost.Test for sharing common setup and teardown actions between tests and organizing tests into suites. -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://legalizeadulthood.wordpress.com>

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[Boost.Test] C++ Unit Tests With Boost.Test, Part 4
by legalize+jeeves＠mail.xmission.com 05 Jul '09

05 Jul '09

[Please do not mail me a copy of your followup] <http://legalizeadulthood.wordpress.com/2009/07/05/c-unit-tests-with-boost-t…> In Part 3 of this series, we completed Bob Martin's Prime Factors Kata using test-driven development and unit tests written in C++ with Boost.Test. In this part, I will discuss test-driven UI development. Please post comments to the blog. Thanks! -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://legalizeadulthood.wordpress.com>

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Request for generalized `overview' documentation
by tom fogal 05 Jul '09

05 Jul '09

Hi all, I'd like to put in a request for an additional kind of documentation to be distributed with boost. Current boost documentation, I would argue, is very good at answering questions of the form, 'How can I get Boost.X to do functionalityA?' It is not so good at answering the question, 'How can I obtain functionalityA?' To make a long story (somewhat) short, especially when one wants to do something relatively simple and limited, many boost libraries might be able to fill the role. Today's problem is providing a callback mechanism. A simple freestanding function would work fine. Yet at some point, I know somebody is going to wish they could pass a member function, and then someone else will want to pass any object that implements operator(), and then ... There are multiple libraries which I might use to fulfill this goal. What's lacking is a way to (quickly!) figure out which one I want. >From limited skimming, it seems like Boost.Function might do what I want. However, I might consider that a future use case would allow multiple functions to get called from a single callback `site', which would cause me to choose Boost.Signals. If I'm concerned with thread safety, it seems like I might choose Boost.Signals2. I think Boost.FunctionTypes might fit in here somehow too, but I'm still not sure. In this case, I'm concerned with compilation time, but execution time is not likely to be important. It seems like the only way I could determine which library fits best given that restriction is to implement a few simple programs. Given today's inquiry, a short blurb like the following would go a long way: Boost.X grew out of frustrations implementing nitz-frobbing in terms of Boost.Y. Along the way, it was discovered that X provided a natural vehicle for standardizing foo-like syntax such that compile-time errors could be generated in the bar case. The price paid for the ability to easily frob your nitzes is memory. X must store 16 additional words of state for every nitz to guarantee an O(log n) traversal of a nitz-holding container (it's actually 2*log n due to the requirement of identifing the internal node with the highest stitzel before the frobbing can start). Note: Boost.Z provides an alternative methodology for foo-ing which adheres to the SomeConceptA protocol (which X does not). There's an incredible amount of useful information here. If Boost.Y looked relevant before, I could presumably decide if I should go with that based on whether I think I'll need to frob the nitz in the future. Presumably looking at the 30-second blurb from Y and Z would let me reason out which library I would want for foo-ing. The performance characterization gives the information I need to choose between implementations with a good O() versus, say, implementations which will fit all of my nitzes in cache on my most important platform. You might also think of an alternative form, which categorizes Boost libraries and provides a `category introduction' to overview them. Given the somewhat distributed nature of Boost libraries, I figure a blurb per library is easier, but from a user's perspective I'm not convinced it matters. Thanks for reading, -tom

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