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[Boost.Serialization] Dealing with offsets
by Júlio Hoffimann 27 Jul '11

27 Jul '11

Dear Boost users/devs, Suppose i have a simulator S: R^n ---> R such that each run is during about 1 hour. Even using Boost.MPI, is expensive to run thousands of simulations all the time. To solve this problem, i'm wondering in use Boost.Serialization to store the pairs inputs/output in a boost::serialization::binary_archive and check before run if those inputs had an associated output already. By reading the Boost.Serialization docs, i can't found a way to deal with offsets in the archive, in really i don't know if it's possible. My intention is to get an archive like: 1.3, 2.5, ..., 4.6 0.1, 4.3, ..., 5.0 ... ... 123445 1234542 9893 1234 ... and skip the first rows, which are the inputs, to get the associated outputs. If you have any advice to solve this or know another more appropriate approach for this restart feature, please let me know. The second option i have in mind is work with C++ file streams and save the floating points by using the low-level std::fstream::read std::fstream::write functions. Best regards, Júlio.

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ASIO async_accept() and c++2011 lambas
by Claude 27 Jul '11

27 Jul '11

Hi, I found this example for use the async_accept() method: void accept_handler(const boost::system::error_code& error) { if (!error) { // Accept succeeded. } } ... boost::asio::ip::tcp::acceptor acceptor(io_service); ... boost::asio::ip::tcp::socket socket(io_service); acceptor.async_accept(socket, accept_handler); It is possible use the async_accept with a (c++0x) lambda function instead of the function accept_handler()? -- View this message in context: http://boost.2283326.n4.nabble.com/ASIO-async-accept-and-c-2011-lambas-tp36… Sent from the Boost - Users mailing list archive at Nabble.com.

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Chrono.hpp
by Sarkar, Arup 27 Jul '11

27 Jul '11

Hi: I am just getting to know boost library, I was able to execute the lambda program mentioned in the documentation without any problem. Now I am trying out with chrono, so I am doing the following, I am getting an error. #include <boost/chrono/chrono.hpp> Same is true for posix_time.hpp as well, the error says Cannot open include library file: 'boost/chrono/chrono.hpp' No such file or directory, but it is not complaining when I am using lambda. Can anyone please help. Regards, Arup

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Is now a good time to use Boost.Log?
by bear330 27 Jul '11

27 Jul '11

Hi, I am looking for a good logging library, I very like boost libraries and almost all my C++ projects use it. So the Boost.Log is the first choice I am considering. But Boost.Log is accepted for a long time and still not ship with latest Boost library. I heard about it is developing v2. I am not sure about its API will change a lot or not. If I use Boost.Log v1 now, would that be painful to upgrade to final Boost.Log that ships with Boost library? And is Boost.Log v1 efficient enough or stable enough just like other boost libraries? (I concern about that because it is not ship with boost release for a long time). Thanks a lot. -- View this message in context: http://boost.2283326.n4.nabble.com/Is-now-a-good-time-to-use-Boost-Log-tp36… Sent from the Boost - Users mailing list archive at Nabble.com.

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[Python] Handling std::vector and boost::tuple
by Johan Råde 27 Jul '11

27 Jul '11

The following code fails with the error message: "Boost.Python.ArgumentError: Python argument types in m.f(list) did not match C++ signature: ..." How do I make it work? Do I have to write a custom translator? C++: void f(const vector<tuple<double, string, bool> >& x); BOOST_PYTHON_MODULE(m) { def("f", &f); } Python: import m m.f([(4.3, 'abc', True)]) Thank you, Johan Råde

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boost::units units symbols/names
by Michael Powell 26 Jul '11

26 Jul '11

Boost::units users, How do I get at the unit symbol or name? I think this type thing would be essential when receiving and parsing textual quantities from a client side application. So say I am given "1.0 in" or "2.3 m/s^2" and so on, and be able to translate that into the appropriate compile-time dimensional quantity. Thanks... Regards, Michael

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[cross-compiling]
by Wilde, Donald S 26 Jul '11

26 Jul '11

We have a somewhat tricky cross-compile, and I'm hoping I can get some feedback to help me be sure that I'm doing this right. In my user-config.jam, I (think I) need to put the following line: Using gcc : 4.5.1 : : "/path/to/target/compiler" <compileflags> -I/path/to/sdk/includes <cxxflags> -std=c++0x <cflags> -Wall -march=atom Does that sound right? Does boost depend on standard precompiled libraries like libstdc++.so? I've been bit by having the system crash hard in different places, and I suspect that sometimes this is caused by the fact that the host is i686 linux and the target is an atom-based SoC with custom linux libraries. Boost wants to pull them from the host, so I need to tell it everything it should NOT pull silently. Correct? Do I also need a <linkflags> -L/path/to/target/lib/directory? -- Don Wilde DHG | TSPO 480-552-3792 donald.s.wilde(a)intel.com

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[Review] Lockfree review: two more days left
by Hartmut Kaiser 26 Jul '11

26 Jul '11

Hi all, We have two more days left for the review of Tim Blechmann's Lockfree library. If you're interested in this library, please consider contributing a review! Please see the original (slightly corrected) announcement below: ----------------------------------------------------- About the library: Boost.Lockfree provides implementations of lock-free data structures. Lock-free data structures can be accessed by multiple threads without the necessity of blocking synchronization primitives such as guards. Lock-free data structures can be used in real-time systems, where blocking algorithms may lead to high worst-case execution times, to avoid priority inversion, or to increase the scalability for multi-processor machines. The following data structures are provided: - boost::lockfree::fifo, a lock-free fifo queue - boost::lockfree::stack, a lock-free stack - boost::lockfree::ringbuffer, a wait-free single-producer/single-consumer ringbuffer. The library is accessible from here: http://tim.klingt.org/boost_lockfree.tar.gz. Boost.Lockfree depends on C++0x atomics. They are not well supported with current compilers yet. For this reason Boost.Lockfree depends on the *unreviewed* Boost.Atomic library, that emulates C++0x atomics for C++98. This review is about Boost.Lockfree and not about Boost.Atomic, although it is included in the tarball and the git repository. If Boost.Lockfree will be accepted, it won't be merged into trunk before Boost.Atomic is accepted. --------------------------------------------------- Please always state in your review, whether you think the library should be accepted as a Boost library! Additionally please consider giving feedback on the following general topics: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? Regards Hartmut Review Manager

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[boost-users] [geometry] segment concept
by Sergei Politov 26 Jul '11

26 Jul '11

Hello, I play with new boost geometry library. There is thing that I don't understand, possible it is bug. I'm trying to register segment concept. It is struct with fields named "point1" and "point2", that represents endpoints of this segment. I've specified tag, point_type, indexed_access for this struct. And length works fine. But intersection requires that this struct contains fields named "first" and "second". I'm new to this library, so I don't know whether it is bug in library or my code. I've attached minimal c++ file that reproduces the problem. If I uncomment //#define point1 first //#define point2 second all compiles and works fine. Best Regards, Sergey

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[Serialization] Writing an old version of a class
by Don 26 Jul '11

26 Jul '11

I apologize if this is a duplicate posting. I sent this 2 days ago, and it appears in the archives, but I never received it back from the list and there have been no replies, so I am posting it again. Using boost serialization, I would like to be able to write an old version of a class, so that I can save data in an "old" format to allow other users with an old version of my program to read the file. I see from the archives that this has come up before, and Robert Ramey indicated it was doable and on the todo list, but I don't see it in the release notes or documentation. Did anything every come of this? Or, has anyone else done this? Any suggestions on how to accomplish this? Thanks, Don

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