February 2012 - Boost-users - lists.preview.boost.org

PP: commas issues
by MM 29 Feb '12

29 Feb '12

Hi, I am trying to generate a list of instances of the same template with different pairs of args, to populate a mpl container, with PP so, mpl::vector< tmpl<A::x,A::y>, tmpl<B::x,B::y>, tmpl<C::x, C::y> > i'm having trouble with the commas. I successfully generate the pp sequence (tmpl<A::x,A::y>)(tmpl<B::x,B::y>) (tmpl<C::x, C::y>) but from this to get the enumeration, it's impossible using SEQ_ENUM, because the sequence contains commas MM

2 1

[multi_array] How to specify degenerate at runtime?
by Anton Daneyko 29 Feb '12

29 Feb '12

Greetings to Boosters, I have a 3D multi_array and I would like to make 2D slices using dimensions specified at runtime. I know the index of degenerate dimension and an index of slice, that I want to extract in that degenerate dimension. Currently the ugly workaround looks like that: if (0 == degenerate_dimension) { Slice slice = input_array[boost::indices[slice_index][range()][range()]]; } else if (1 == degenerate_dimension) { Slice slice = input_array[boost::indices[range()][slice_index][range()]]; } else if (2 == degenerate_dimension) { Slice slice = input_array[boost::indices[range()][range()][slice_index]]; } Is there a more beautiful way to construct index_gen object? Something like that: var slicer; for(int i = 0; i < 3; ++i) { if (degenerate_dimension == i) slicer = boost::indices[slice_index]; else slicer = boost::indices[range()]; } Slice slice = input_array[slicer]; It seems each subsequent call to boost::indices::operator[] returns a different type depending on the dimensionality, so there's no way to use a single variable, that can hold the temporary index_gen object.

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iterator_facade with incomplete type as Value argument
by Philipp Moeller 29 Feb '12

29 Feb '12

I've tried writing an iterator with iterator_facade that returns itself as the result of dereference, but the Value template argument requires a complete type because it tries to make a difference between returning by value or reference if Value is_pod (as far as I understand). #include <boost/iterator/iterator_facade.hpp> class iter : public boost::iterator_facade< iter, iter, boost::forward_traversal_tag > { public: void fancy_non_iterator_member(); private: friend class boost::iterator_core_access; void increment() { } bool equal(iter const& other) const { return true; } iter& dereference() const { return const_cast<Derived&>(static_cast<const Derived&>(*this)); } }; Is this the intended behavior of iterator_facade? Is there some workaround? Would such an iterator actually be conforming? -- Philipp Moeller GeometryFactory

1 1

boost python & context manager/with statement
by Avi Bahra 29 Feb '12

29 Feb '12

Does boost python support context management using the with statement? In my case I need to manage __enter__/__exit__ on the c++ side. Could not find any examples for this in the documentation. Any help appreciated. Best regards, Ta, Avi

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Using boost with PathScale v4.x under Linux
by Roberto Fichera 29 Feb '12

29 Feb '12

Hi there, I've compiled the last boost v1.49 against PathScale v4.x compiler under 64bit linux distribution, but when compiling certain library that uses the boost/numeric/interval/rounded_transc.hpp include file, I end up on getting some error regarding asinh(), acosh() and atanh() which were searched in the std namespace. Compiling the same library against g++ or MSVC goes pretty straight without problems. /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_exact<T, Rounding>::asinh_down(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:42: error: 'std::asinh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_exact<T, Rounding>::asinh_up(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:42: error: 'std::asinh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_exact<T, Rounding>::acosh_down(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:43: error: 'std::acosh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_exact<T, Rounding>::acosh_up(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:43: error: 'std::acosh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_exact<T, Rounding>::atanh_down(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:44: error: 'std::atanh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_exact<T, Rounding>::atanh_up(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:44: error: 'std::atanh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_std<T, Rounding>::asinh_down(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:77: error: 'std::asinh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_std<T, Rounding>::asinh_up(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:77: error: 'std::asinh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_std<T, Rounding>::acosh_down(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:78: error: 'std::acosh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_std<T, Rounding>::acosh_up(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:78: error: 'std::acosh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_std<T, Rounding>::atanh_down(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:79: error: 'std::atanh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_std<T, Rounding>::atanh_up(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:79: error: 'std::atanh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_opp<T, Rounding>::asinh_down(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:122: error: 'std::asinh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_opp<T, Rounding>::asinh_up(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:122: error: 'std::asinh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_opp<T, Rounding>::atanh_down(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:123: error: 'std::atanh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_opp<T, Rounding>::atanh_up(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:123: error: 'std::atanh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_opp<T, Rounding>::acosh_down(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:132: error: 'std::acosh' has not been declared /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp: In member function 'T boost::numeric::interval_lib::rounded_transc_opp<T, Rounding>::acosh_up(const T&)': /TempData/boost_1_49_0_pathscale/boost/numeric/interval/rounded_transc.hpp:132: error: 'std::acosh' has not been declared Thus, I had a look in the boost include file boost/numeric/interval/detail/bugs.hpp and look like that apply the patch below fixes the compilation error: --- numeric/interval/detail/bugs.hpp.orig 2012-02-29 10:44:06.876597264 +0100 +++ numeric/interval/detail/bugs.hpp 2012-02-29 10:18:42.831581398 +0100 @@ -25,7 +25,7 @@ #else # define BOOST_NUMERIC_INTERVAL_using_math(a) using std::a # if defined(BOOST_HAS_INV_HYPERBOLIC) -# if defined(__GLIBCPP__) || defined(__GLIBCXX__) +# if defined(__GLIBCPP__) || defined(__GLIBCXX__) || defined(__GLIBC__) # define BOOST_NUMERIC_INTERVAL_using_ahyp(a) using ::a # else # define BOOST_NUMERIC_INTERVAL_using_ahyp(a) using std::a does anyone can comment? Thanks in advance, Roberto Fichera.

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[PREDEF] Review ends today
by Joel Falcou 29 Feb '12

29 Feb '12

The review of Boost.PRedef by Rene Rivera is ending today, February 29th. I recall to all people wanting to submit a formal review to do so. Regards

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Metaprogramming Question
by John M. Dlugosz 28 Feb '12

28 Feb '12

I've not had much opportunity to do much template metaprogramming in my work, but I've kept up with my reading. So, might I get some advice on how to approach this problem? I'm thinking of an assert-like statement that follows the syntax of Boost.Format, thus avoiding the variadic argument list. MY_FANCY_ASSERT (cond, "format string") % arg % arg; works if the macro expands to an unnamed temporary, whose destructor does the interesting work if the first argument is false. my_assert_formatter_type (cond, "cond", __FILE__, __LINE__, "format string") This is easy to do, simply deriving from boost::formatter, I would think. But, I want to avoid doing any work except on failure. This means remembering the arguments including the following %arg stuff, and passing everything through to Boost.Format based on the condition. So I'm thinking that template metaprogramming can let me collect all the arguments (any number of them) into one object, efficiently at compile time. So, what approach should I use? Plain MPL and classic metaprogramming? Fusion? Phoenix? and any concrete suggestions on how to proceed, or pointers to similar works? Thanks, —John

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boost::python handles boost::shared_ptr specially...
by Neal Becker 28 Feb '12

28 Feb '12

Will it just work if I use std::shared_ptr instead?

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WIN64 vs _WIN64
by Roberto Fichera 28 Feb '12

28 Feb '12

Hi All, I got a compilation error while compiling a library under Win64 arch that includes the boost/numeric/interval/msvc_rounding_control.hpp c:\boost_1.48\include\boost/numeric/interval/detail/msvc_rounding_control.hpp(33) : error C4235: nonstandard extension used : '_asm' keyword not supported on this architecture c:\boost_1.48\include\boost/numeric/interval/detail/msvc_rounding_control.hpp(33) : error C2065: 'FLD' : undeclared identifier c:\boost_1.48\include\boost/numeric/interval/detail/msvc_rounding_control.hpp(34) : error C4235: nonstandard extension used : '_asm' keyword not supported on this architecture So I checked the code under boost/numeric/interval/detail/msvc_rounding_control.hpp and it seems that it does a preprocessor check against WIN64 instead of _WIN64 namespace boost { namespace numeric { namespace interval_lib { namespace detail { #if BOOST_MSVC < 1400 || *defined(WIN64)* extern "C" { double rint(double); } #else inline double rint(double x) { _asm FLD [x] ; _asm FRNDINT ; //_asm RET ; } #endif Is there any reason why do not check against _WIN64 instead of WIN64 since the boost does always check against _WIN64? _WIN64 is also already pre-defined as normal MSVC definition when targeting x86_64 archs. [roberto@roberto include]$ grep -R WIN64 * boost/serialization/force_include.hpp:#elif ! defined(_WIN32) && ! defined(_WIN64) boost/detail/win/synchronization.hpp: #if defined(_WIN64) boost/detail/win/basic_types.hpp:# ifdef _WIN64 boost/intrusive/detail/mpl.hpp:#if defined(_MSC_EXTENSIONS) && !defined(__BORLAND__) && !defined(_WIN64) boost/python/converter/builtin_converters.hpp:# if defined(_MSC_VER) && defined(_WIN64) && PY_VERSION_HEX < 0x03000000 boost/xpressive/xpressive_fwd.hpp:# if (defined(_WIN32) || defined(_WIN64) || defined(_WINCE)) \ boost/thread/win32/thread_primitives.hpp:# ifdef _WIN64 boost/regex/config.hpp:# if(defined(_WIN32) || defined(_WIN64) || defined(_WINCE)) \ boost/signals2/detail/lwm_win32_cs.hpp:#if defined(_WIN64) boost/config/compiler/intel.hpp:#if (!(defined(_WIN32) || defined(_WIN64)) && defined(__STDC_HOSTED__) && (__STDC_HOSTED__ && (BOOST_INTEL_CXX_VERSION <= 1200))) || defined(__GXX_EXPERIMENTAL_CPP0X__) boost/config/compiler/intel.hpp:#if defined(_WIN32) || defined(_WIN64) boost/smart_ptr/detail/lwm_win32_cs.hpp:#if defined(_WIN64) *boost/numeric/interval/detail/msvc_rounding_control.hpp:#if BOOST_MSVC < 1400 || defined(WIN64)*

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C++ guru required!
by Robert Ramey 27 Feb '12

27 Feb '12

I've got a really dumb question. My question is illustrated by the following code snippit. template<class T, class U> T inline operator%(const T & lhs, const U & rhs) { if(0 == rhs) throw std::domain_error("Divide by zero"); if(boost::is_same<T, boost::uintmax_t>::value && boost::numeric::is_signed<U>::value ){ if(1 == rhs || -1 == rhs) // is this dropped? overflow("unsigned type can hold this result"); } return lhs % rhs; } I would like to think that the second if is always dropped from the compile for a particular pair of types since this can be evaluated at compile time. If I'm correct, I can replace some tedious template metaprogramming for some straightforward and transparent code inserted in a convenient code inserted in the most convenient place. Andre Alex... gave a talk at "Going Native" proposing a "static if" for this case. But I don't see the necessity for for this since I would assume that the compiler just optimises away the "dead" code. I've compiled the above and it seems to do what I want but still I wonder. Basically I see lots of applications of variations on this idea to get the benefits of tmp without the attendent pain. Am I missing anything here? Robert Ramey

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[quickbook] how to use
by Nathan Ridge 27 Feb '12

27 Feb '12

Hello, I am trying to use QuickBook to write documentation for a project (that's not a Boost library), and I have a basic question about how to use it. So far I've followed the setup instructions on this page, built the quickbook executable by running bjam in BOOST_ROOT\tools\quickbook, written a .qbk file in QuickBook format, and ran the quickbook executable on my .qbk file to produce an XML file which looks like BoostBook XML. Now how do I go about generating HTML or PDF from that BoostBook XML file? Thanks, Nate

2 1

[build] Is there any interest in a configure auto generator for boost-build?
by Tianjiao Yin 27 Feb '12

27 Feb '12

Hello all: Boost build configure (site-config.jam) is not easy to write for me, especially when I install some new compilers or tools. So I wrote a script to generate the configure in "/etc/site-config.jam" automatically for myself. You can get the whole source code here: http://ideone.com/kkI2G When I run this script by using argument "--setup", it will generate a new configure in "/etc/site-config.jam" like this: http://ideone.com/4yWyI I am using archlinux, not tested in any other platform. For archers, this script is part of boost-build-nightly in AUR, it works for me. BTW, boost-build 2.0_m12 is in the archlinux official repository. But this version is too outdated to build many examples in the boost 1.48.0. When m13 release? Regards, Tianjiao

1 0

[Container] comment on slist/forward_list documentation
by Brian Wood 26 Feb '12

26 Feb '12

Iiuc, Boost.Container implements slist but not forward_list. I'd like to suggest tweaking the following sentence. *"Boost.Container* updates the classic slist container with C++11 features like move semantics and placement insertion and implements it a bit differently for the standard C++11 forward_list." ^^ It might be better to say "and implements it a bit differently than the standard C++ forward_list." ? I wondered if you had both an slist and a forward_list implementation for a while and did some other checking to figure out what was in the library. http://www.boost.org/doc/libs/1_49_0/doc/html/container/non_standard_contai… Shalom Brian Wood Ebenezer Enterprises http://webEbenezer.net

2 1

[Iterators] How to implement proxy iterators?
by Oswin Krause 26 Feb '12

26 Feb '12

Hi Everybody, I'm trying to implement a proxy_iterator for ublas::matrix which should behave as an iterator over the matrix rows. My "obvious" solution does not seem to work: typedef boost::numeric::ublas::matrix<double> Matrix; typedef boost::numeric::ublas::matrix_row<Matrix> MatrixRow; typedef boost::numeric::ublas::vector<double> Vector; struct MatrixIterator: public boost::iterator_facade< MatrixIterator, Vector,//the semantic value type is a Vector boost::random_access_traversal_tag, MatrixRow//reference is a row of a matrix >{ //snip constructors private: friend class boost::iterator_core_access; //snip iterating stuff //fun part MatrixRow dereference() const { return row(*m_matrix,m_element); } std::size_t m_element; Matrix* m_matrix; }; which reuslts in an error that MatrixRow can't be implicitely casted to Vector. Which is correct. At the moment I'm using a 90% hacked workaround which changes the ValueType of the Iterator to MatrixRow. This seems to work as long as I don't use algorithms which rely on the actual value_type of the iterator (for example iter_swap as implemented in the gnu libstdc++ will fail miserably even though a correct swap is implemented for the MatrixRow...different story ) Since I need std::random_shuffle I am out of luck. I tried to find the actual requirements of iterator_facade with respect to ValueType/ReferenceType in the documentation, but was not able to find them. Does someone now a solution to this problem which works and results in an iterator which can safely be used in random_shuffle? Or can point me to the correct requirements? Greetings from Germany, Oswin Krause

2 5

Linking problem
by Johan Råde 26 Feb '12

26 Feb '12

I built Boost with the command b2 toolset=msvc-10.0 address-model=32 link=static runtime-link=shared threading=multi stage I'm linking statically with Boost and dynamically with the CRT (compiler option /MD). I get the error message LINK : fatal error LNK1104: cannot open file 'libboost_iostreams-vc100-mt-1_49.lib' What might the problem be?

3 4

any progress on the logger?
by Victor Whiskey Yankee 25 Feb '12

25 Feb '12

Hello, Any progress on getting the logger into an official release? Thanks, Vic

2 1

[phoenix] Extending actors
by paul Fultz 25 Feb '12

25 Feb '12

Hi all, I am wanting to extend actors to access a member variable from the class. In the examples they show extending an acotr by using a lazy function to call the function. I was thinking I could use a lazy function to access the member, something like this: template <typename Expr> struct point_actor : actor<Expr> { typedef actor<Expr> base_type; typedef point_actor<Expr> that_type; point_actor( base_type const& base ) : base_type( base ) {} typename expression::function<x_impl, that_type>::type x; typename expression::function<y_impl, that_type>::type y; }; Where x_impl and y_impl are lazy functions that access the x and y variable. Would this work as member variables, rather than member functions? Also, why wouldnt the second parameter to expression::function take just actor instead of just point_actor<Expr>? Does that make sense? The reason I ask is I would like to control the actor that is returned and do something like this(using the above actor): template <typename Expr> struct rect_actor : actor<Expr> { typedef actor<Expr> base_type; typedef rect_actor<Expr> that_type; rect_actor( base_type const& base ) : base_type( base ) {} typename expression::function<top_impl, point_actor >::type top; typename expression::function<bottom_impl, point_actor >::type bottom; }; expression::terminal<phoenix::argument<1>, rect_actor > arg1; (cout << arg1.top.x)(my_rect()); Does that make sense? I can't seem to find any reference on the predefined expressions, and I also can't find the header file for expression::function. Finally, the is_actor trait doesn't seem work for extended actors.Is there a workaround for that? Thanks, Paul

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Boost 1.49.0 release notice
by Beman Dawes 24 Feb '12

24 Feb '12

Release 1.49.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains one new library (Heap) and numerous enhancements and bug fixes for existing libraries. For details, including download links, see http://www.boost.org/users/news/version_1_49_0 You can also download directly from SourceForge: http://sourceforge.net/projects/boost/files/boost/1.49.0/ To install this release on your system, see http://www.boost.org/doc/libs/release/more/getting_started/index.html Thanks, --The Boost release team Beman Dawes Daniel James Eric Niebler Rene Rivera Vladimir Prus

3 2

Detecting file encoding
by norulez＠me.com 24 Feb '12

24 Feb '12

Hi, is there a way in boost to detect the encoding of a file? Thanks in advance Best Regards NoRulez

1 0

iterator_adaptor: making dereference of adapted tree node* return node value
by Rob Desbois 24 Feb '12

24 Feb '12

I have the following iterator_adaptor type: template< class NODE > struct node_iterator: public boost::iterator_adaptor< node_iterator<NODE>, // Derived NODE*, // Base typename NODE::value_type // Value > { typename NODE::value_type dereference() const { return this->base_reference()->data(); } }; // and later: typedef detail::node_iterator<node_type> iterator; typedef detail::node_iterator<const node_type> const_iterator; This throws up the issue that in const_iterator, Value is not const, producing the following error: /usr/include/boost/iterator/iterator_facade.hpp:517:32: error: invalid initialization of non-const reference of type ‘container::detail::node_iterator<const container::detail::node<long unsigned int> >::reference {aka long unsigned int&}’ from an rvalue of type ‘container::detail::node<long unsigned int>::value_type {aka long unsigned int}’ I could do some type traits magic with is_same, is_const and add_const to add the constness to Value if present on NODE, but is this the right way to do it? I've also thought about indirect_iterator - but adding operator*() to the node type seems not quite right. Perhaps transform_iterator...or is there some different method that might be more suitable? TIA, --rob -- Rob Desbois Blog: http://theotherbranch.wordpress.com/ "I disapprove of what you say, but I’ll defend to the death your right to say it", Voltaire

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[posix_time] from_time_t bug
by Matthew Jenks 24 Feb '12

24 Feb '12

Hello, I am running into a problem with boost::posix_time::from_time_t() on a PC with, windows xp, visual studio 2010. When I input a number larger than the decimal equivalent of 0x7FFFFFFF (maximum posssible int32) into the function it returns a ptime with a date of 1902 or something close to. I assume the UNIX equivalent of time_t is a int32 and that is why I am having this problem, but I know a time_t is the equivalent to __int64 in windows xp. Is there is a MACRO define I am missing or is this a bug that needs to be fixed with this function so that it can accept the windows equivalent of time_t? Shouldn't this function accept and convert larger intigers thank int32 to a ptime or do I have to write my own? Thanks, Matt

2 1

Getting Mac address once ip address
by radha bhavani 24 Feb '12

24 Feb '12

Hi, Is there any api available in boost library to get mac addess of the device if ip address is know. Regards, Bhavani

2 1

[MultiIndex] how to rebuild index
by Igor R 24 Feb '12

24 Feb '12

Hello, What's the most simple way to rebuild an index? If elements change without notifying the container, would iterating from begin to end and calling modify() with no-op - do the job? (I remember there already was such a question, but can't find it.) Thanks.

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[asio] Issue with resolver query for 64-bit browsers (IE)
by Jacques, Keiko 23 Feb '12

23 Feb '12

I am writing a browser plugin which needs to get the size of a file using the HTTP HEAD request. In order to send the request I am using the boost socket and the boost::asio::ip::tcp::resolver::query to get the ip address and service port. I am basically using code from the asio sync_client sample provided with Boost 1.48.0. using boost::asio::ip::tcp; boost::asio::io_service io_service; tcp::resolver resolver(io_service); tcp::resolver::query query(hostname, "http"); tcp::resolver::iterator endpoint_iterator = resolver.resolve(query); tcp::resolver::iterator end; This works fine when I run this on a Windows platform (Windows 7) using 32-bit browsers such as Firefox, Chrome, and IE. This also works fine when I run this as a desktop application through a test driver on a Windows (Vista , Windows7)64-bit platform. However, when I run this as a browser plugin on the Windows Vista 64-bit platform using IE (64-bit) it seems to crash on the line: tcp::resolver resolver(io_service); I'm not sure if this is a Boost issue or an IE issue, so I was wondering if anyone knows of any incompatibility issues and/or limitations with Boost and IE (64-bit) which could cause this to happen. Thanks Keiko ________________________________ This e-mail and any attachments may contain confidential material for the sole use of the intended recipient. If you are not the intended recipient, please be aware that any disclosure, copying, distribution or use of this e-mail or any attachment is prohibited. If you have received this e-mail in error, please contact the sender and delete all copies. Thank you for your cooperation.

1 0

REGEX Don't understand the matching behavior: regex_search vs. regex_match
by Andy Falanga (afalanga) 23 Feb '12

23 Feb '12

Hi, I understand enough that regex_match() searches for matches based on the entire input string and apparently regex_search() allows for matches of the expression within the input string (i.e. the expression need not match the entire input string). However, I'm not understanding why the following happened: const char* pInput("Loc info: Channel 2, Target 0, Lun 0"); boost::cmatch found; boost::regex expression(".*Channel ([[:digit:]]{1,3})); // looking for the channel number only if(boost::regex_match(pInput, found, expression, boost::regex_constants::match_partial)) { std::cout << "Matched: " << std::atoi(found[1].first) << std::endl; } When using the above, with regex_match(), the match succeeded but the output string was: "Matched: 0". What?!? If the expression was matched, why did the capture group 1 contain 0? How should the expression have been made? That's what I don't understand. I've found that what I want is accomplished with altering the above thusly: const char* pInput("Loc info: Channel 2, Target 0, Lun 0"); boost::cmatch found; boost::regex expression("Channel ([[:digit:]]{1,3})); // looking for the channel number only if(boost::regex_search(pInput, found, expression)) { std::cout << "Matched: " << std::atoi(found[1].first) << std::endl; } This gives me: "Matched: 2." Which is what I'm looking for. I'd like to understand why regex_match() wasn't giving me what I wanted. Thanks everyone, Andy

2 2