- Boost-users - lists.boost.org

Conditionally show_progress ?
by David Doria 14 May '09

14 May '09

I would like to do something like this void Conditional(const bool show) { unsigned int NumIters = 1e9; boost::progress_display show_progress; if(show) show_progress = boost::progress_display(NumIters); double temp; for(unsigned int i = 0; i < NumIters; i++) { temp = sin(i) / i; if(show) ++show_progress; } } It doesn't seem like I can instantiate a progress_display like this. Is there a way to conditionally have a progress display? Thanks, Dave

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[BGL] A bug in graphviz parser ?
by Dmitry Bufistov 14 May '09

14 May '09

Hi, read_graphviz() parser considers names "b" and b as two different names while the native parser from AT&T does not. Regards, Dmitry

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[boost] [Test] [1.35] How would one access a global fixture's member?
by Stephen Watjen 14 May '09

14 May '09

I came across an example of a global fixture macro in the docs, 'BOOST_GLOBAL_FIXTURE( fixture )' The example that is provided with Boost demonstrates setup and teardown utilizing the constructor and destructor of the fixture passed through the macro. It does not show members in this global fixture. I added a member to the fixture and tried to access it within a test case and I received a compiler error stating that the variable had not been declared in this scope. Is it possible to access a global fixture member? If yes, then how? struct Fixture { const char* str; } BOOST_GLOBAL_FIXTURE( Fixture ) BOOST_TEST_CASE( testGlobalFixture ) { BOOST_CHECK( str != 0 ); } // The above code fails to compile stating: 'str' undeclared (first use this function) Steve Watjen

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Boost::asio // Barrier synchronization
by Dan Eaton 14 May '09

14 May '09

Hello, I'll soon be implementing barrier synchronization over TCP/boost::asio (much like MPI_Barrier) -- has anyone else implemented something similar? Is there any guidance you can offer? Many thanks :) Danny Dan Eaton Software Developer Acceleware Corp. (TSX-V:AXE) www.acceleware.com<http://www.acceleware.com/> Phone: +1.403.249.9099 Ext.295 Fax: +1.403.249.9881 Email: daniel.eaton(a)acceleware.com<mailto:daniel.eaton@acceleware.com> Get superpowered! Acceleware gets your products to market faster, better and stronger! This e-mail may contain information that is privileged and confidential and subject to legal restrictions and penalties regarding its unauthorized disclosure or use. You are prohibited from copying, distributing or otherwise using this information if you are not the intended recipient. If you have received this e-mail in error, please notify us immediately by return e-mail and delete this e-mail and its attachments from your system. Thank you. (c) 2008 Acceleware, Inc. All Rights Reserved

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[Accumulators] Are all statistics lazily evaluated by default?
by pete＠pcbartlett.com 14 May '09

14 May '09

Hi all, I really like the range of statistical properties that the accumulators library supports but am a little unclear about the laziness properties of the library. Suppose I wish to offer a interface that lets the user send a bunch of data and request the k-th moments where k is specified by the user at runtime. Will the accumulator_set accumulator_set< value_type , ba::tag::moments > acc; where k_max >= k (but the inequality may be strict) be efficient. I.e. I only do the calculations necessary to get the k-th moment not the k-max-th? The reason I ask is the documentation makes a distinction between variance and lazy_variance, but this distinction does not seem to be made for other statistics. Thanks in advance for any assistance, Pete

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(Boost.Python) How to print from C++ to the same stream as Python's 'print' does?
by Dietrich Bollmann 14 May '09

14 May '09

Hi, I would like to print from C++ to the same stream as Python's 'print' command does. I am using an embedded Python shell and when using std::cout nothing is printed at all... Currently I am using the following code: std::ostringstream oss; oss << "test\n"; std::string cs = oss.str(); PySys_WriteStdout(cs.c_str()); I wonder if there is an easier way to get the same result? Thanks, Dietrich

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Re: [Boost-users] Tips on implementing a function queue with unique queue items (compare function problem)
by Peter Åberg 14 May '09

14 May '09

Excellent, spot on, thanks gurus :-) /Peter Åberg Steven Watanabe wrote: > If the caller of push knows the type of the function object, > then you can template the push function. > > template<class F> > void push(const F& f) { > if(std::find_if(queue.begin(), queue.end(), f == _1) != queue.end()) { > queue.push_back(item); > } > } > > This is going to be pretty inefficient because of the linear search, > but the same idea applies if you want to store the function objects > in a data structure that supports faster lookup. > > In Christ, > Steven Watanabe > > Nat Goodspeed Wrote: > You're right that we can't compare two boost::function objects, but it > *is* permitted to compare a boost::function with an rvalue that could > initialize it. If you make your push() method a template accepting an > argument of arbitrary type, presumably you could compare each existing > item with that new value before storing it into the deque. > >

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[test] boost::test equivalent of CppUnit's "protectors" ?
by Tim Day 14 May '09

14 May '09

I've used both CppUnit and boost::test for C++ unittesting. Generally I prefer boost::test, mainly because the auto-test macros minimise the effort to setup tests. But there's one thing I really miss from CppUnit: the ability to register your own custom "protectors", instances of which automatically wrap all the run tests. (Technically, you install a test "listener", and that can wrap each test run in a protector scope. Multiple listeners and nested protectors are possible). I've found these invaluable in the past for monitoring unittests for unexpected side effects (e.g checking code hasn't changed the floating-point unit state flags, or messed with other global state). I can't see any equivalent in the boost::test documentation, although BOOST_FIXTURE_TEST_CASE maybe comes closest. (However, whereas a CppUnit protector can return a bool to indicate pass/fail, it's less clear to me how a fixture destructor should indicate failure). Any suggestions for how to best achieve the same thing as CppUnit's protectors in boost::test (and without updating the body of each test) ? Thanks for any advice Tim

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date_time\gregorian\conversion.hpp : fatal error C1001 MSVC 7.1
by Wilkinson, John (Software) 14 May '09

14 May '09

I get the following error with boost 1.39 and MSVC 7.1 SP1 when including <boost/thread/thread.hpp>. c:\boost_libs\V1_39_0\boost\date_time\gregorian\conversion.hpp(43) : fatal error C1001: INTERNAL COMPILER ERROR (compiler file 'msc1.cpp', line 2708) Please choose the Technical Support command on the Visual C++ Help menu, or open the Technical Support help file for more information This problem was in 1.38 as reported here http://archive.netbsd.se/?ml=boost-users&a=2009-02&t=9851835. I was wondering should I raise a bug? I have searched the bugs database but cannot find it already there. Also can anyone suggest a work-around? Turning the browse facility off is not an option; it is a feature I often use. Thanks John <DIV><FONT size="1"> E-mail confidentiality. -------------------------------- This e-mail contains confidential and / or privileged information belonging to Spirent Communications plc, its affiliates and / or subsidiaries. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution and / or the taking of any action based upon reliance on the contents of this transmission is strictly forbidden. If you have received this message in error please notify the sender by return e-mail and delete it from your system. If you require assistance, please contact our IT department at helpdesk(a)spirent.com. Spirent Communications plc Northwood Park, Gatwick Road, Crawley, West Sussex, RH10 9XN, United Kingdom. Tel No. +44 (0) 1293 767676 Fax No. +44 (0) 1293 767677 Registered in England Number 470893 Registered at Northwood Park, Gatwick Road, Crawley, West Sussex, RH10 9XN, United Kingdom. Or if within the US, Spirent Communications, 26750 Agoura Road, Calabasas, CA, 91302, USA. Tel No. 1-818-676- 2300 </FONT></DIV>

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Boost gzip_decompressor - compilation errors
by einav_i2 14 May '09

14 May '09

Hi! I'm trying to compile the following function on Boost 1.34.1 (Ubuntu 8.04): void decompress(string &gzipString, string & target) { boost::iostreams::filtering_ostream decompressingStream; boost::iostreams::gzip_decompressor gzdc; decompressingStream.push(gzdc); decompressingStream.push(boost::iostreams::back_inserter(target)); decompressingStream << gzipString; boost::iostreams::flush(decompressingStream); } And I'm getting the following (quite long) error: /usr/include/boost/iostreams/chain.hpp: In member function ‘void boost::iostreams::detail::chain_base<Self, Ch, Tr, Alloc, Mode>::push_impl(const T&, int, int) [with T = boost::iostreams::basic_gzip_decompressor<std::allocator<char> >, Self = boost::iostreams::chain<boost::iostreams::output, char, std::char_traits<char>, std::allocator<char> >, Ch = char, Tr = std::char_traits<char>, Alloc = std::allocator<char>, Mode = boost::iostreams::output]’: /usr/include/boost/iostreams/chain.hpp:207: instantiated from ‘void boost::iostreams::detail::chain_base<Self, Ch, Tr, Alloc, Mode>::push(const T&, int, int, typename boost::disable_if<boost::iostreams::is_std_io<T>, void>::type*) [with T = boost::iostreams::basic_gzip_decompressor<std::allocator<char> >, Self = boost::iostreams::chain<boost::iostreams::output, char, std::char_traits<char>, std::allocator<char> >, Ch = char, Tr = std::char_traits<char>, Alloc = std::allocator<char>, Mode = boost::iostreams::output]’ /usr/include/boost/iostreams/chain.hpp:465: instantiated from ‘void boost::iostreams::detail::chain_client<Chain>::push_impl(const T&, int, int) [with T = boost::iostreams::basic_gzip_decompressor<std::allocator<char> >, Chain = boost::iostreams::chain<boost::iostreams::output, char, std::char_traits<char>, std::allocator<char> >]’ /usr/include/boost/iostreams/chain.hpp:453: instantiated from ‘void boost::iostreams::detail::chain_client<Chain>::push(const T&, int, int, typename boost::disable_if<boost::iostreams::is_std_io<T>, void>::type*) [with T = boost::iostreams::gzip_decompressor, Chain = boost::iostreams::chain<boost::iostreams::output, char, std::char_traits<char>, std::allocator<char> >]’ main.cpp:93: instantiated from here /usr/include/boost/iostreams/chain.hpp:233: error: invalid application of ‘sizeof’ to incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false>’ /usr/include/boost/iostreams/stream_buffer.hpp: At global scope: /usr/include/boost/iostreams/stream_buffer.hpp: In instantiation of ‘boost::iostreams::stream_buffer<boost::iostreams::basic_gzip_decompressor<std::allocator<char> >, std::char_traits<char>, std::allocator<char>, boost::iostreams::output>’: /usr/include/boost/iostreams/chain.hpp:246: instantiated from ‘void boost::iostreams::detail::chain_base<Self, Ch, Tr, Alloc, Mode>::push_impl(const T&, int, int) [with T = boost::iostreams::basic_gzip_decompressor<std::allocator<char> >, Self = boost::iostreams::chain<boost::iostreams::output, char, std::char_traits<char>, std::allocator<char> >, Ch = char, Tr = std::char_traits<char>, Alloc = std::allocator<char>, Mode = boost::iostreams::output]’ /usr/include/boost/iostreams/chain.hpp:207: instantiated from ‘void boost::iostreams::detail::chain_base<Self, Ch, Tr, Alloc, Mode>::push(const T&, int, int, typename boost::disable_if<boost::iostreams::is_std_io<T>, void>::type*) [with T = boost::iostreams::basic_gzip_decompressor<std::allocator<char> >, Self = boost::iostreams::chain<boost::iostreams::output, char, std::char_traits<char>, std::allocator<char> >, Ch = char, Tr = std::char_traits<char>, Alloc = std::allocator<char>, Mode = boost::iostreams::output]’ /usr/include/boost/iostreams/chain.hpp:465: instantiated from ‘void boost::iostreams::detail::chain_client<Chain>::push_impl(const T&, int, int) [with T = boost::iostreams::basic_gzip_decompressor<std::allocator<char> >, Chain = boost::iostreams::chain<boost::iostreams::output, char, std::char_traits<char>, std::allocator<char> >]’ /usr/include/boost/iostreams/chain.hpp:453: instantiated from ‘void boost::iostreams::detail::chain_client<Chain>::push(const T&, int, int, typename boost::disable_if<boost::iostreams::is_std_io<T>, void>::type*) [with T = boost::iostreams::gzip_decompressor, Chain = boost::iostreams::chain<boost::iostreams::output, char, std::char_traits<char>, std::allocator<char> >]’ main.cpp:93: instantiated from here /usr/include/boost/iostreams/stream_buffer.hpp:66: error: invalid application of ‘sizeof’ to incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false>’ A similar "compress" function seem to compile without any problems. Any ideas what can cause this error? Thanks, Einav -- View this message in context: http://www.nabble.com/Boost-gzip_decompressor---compilation-errors-tp235353… Sent from the Boost - Users mailing list archive at Nabble.com.

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