April 2011 - Boost-users - lists.preview.boost.org

[phoenix] lazy function to reference or const reference
by alfC 04 Apr '11

04 Apr '11

Hi, Is it possible to use references as the type of the function wrapped by lazy function. The reason I need this is because I need to instatiate a lazy function inside a class and to a class while the class does not have yet a complete definition. The application may sound exotic but I see no intrinsic limitation why the following doesn't work. If this is not possible because an intrinsic limitation of phoenix, is there a workaround? -- Thanks -- Alfredo ... is_odd_impl is defined as in … [View More]

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[Thread] Strange problem.
by Germán Diago 04 Apr '11

04 Apr '11

Hello. I'm designing a class with a locking policy. I have some code that does exaclty this: if (cond) { locking_policy_.lock(); out << message.message(); locking_policy_.unlock(); } return *this; And the lockingpolicy is a class like this one: struct ThreadSafe { boost::mutex io_mutex_; boost::unique_lock<boost::mutex> lock_; ThreadSafe() : io_mutex_(), lock_(io_mutex_, boost::defer_lock) {} void lock() { std::cout << "Locking from " << boost::… [View More]

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[asio] port question
by Pace, Antony [Harman Pro Group UK] 04 Apr '11

04 Apr '11

I would like to use boost::asio on my unusual platform which supports Berkeley sockets and has an RTOS and I have full control of low level interrupts etc. I have seen socket_types.hpp and feel that it is likely that I could find a set of defines that match my stack. I also have a timer interrupt that I imagine could be fed into the asio timer somehow but wonder if anyone could tell me how much work I am letting myself in for with that approach or if I would be better off using the Berkeley … [View More]

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[boost::mutex] Suspicious EINVAL error
by Panagiotis Foteinos 03 Apr '11

03 Apr '11

Hello users. I am running a single thread which locks and unlocks mutexes, and I get the following error: * /usr/include/boost/thread/pthread/mutex.hpp:55: void boost::mutex::lock(): Assertion `!pthread_mutex_lock(&m)' failed, *after a boost::shared_mutex::lock() or a boost::shared_mutex::try_lock(). In fact, I checked the error code that pthread_mutex_lock(&m) returned and it was the EINVAL error (code number 22). The posix manual gives 2 possibilities for this error: … [View More]

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Copy-on-write STL containers
by Alexandr Sterligov 03 Apr '11

03 Apr '11

Is there any interest in a library of STL-compilant containers (vector, deque, map, set, list) with copy-on-write? -- Best regards, Alexander Sterligov

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[BGL] Confusion about iterator_property_map and initialization of OffsetMap
by Cedric Laczny 03 Apr '11

03 Apr '11

Hi, I have modified the astar-cities.cpp example to use an external rank_map based on iterator_property_map. The following should give you an idea: vector<cost> v_vec(num_vertices(g), 0.0); typedef property_map< mygraph_t, vertex_index_t>::type VertexIndexMap; VertexIndexMap v_index = get(vertex_index, g); // Initialization of interest // Create the external property map typedef iterator_property_map< std::vector< cost >::iterator, VertexIndexMap > CostMap;… [View More]

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[MPL] no invoke<T>?
by Noah Roberts 03 Apr '11

03 Apr '11

I had to write an invoke metafunction because I couldn't seem to find one that looked like it was what I needed: template < typename MF > struct invoke { typedef typename MF::type type; }; I've looked through the documentation TOC: http://www.boost.org/doc/libs/1_42_0/libs/mpl/doc/refmanual/refmanual_toc.h… Is there something I'm missing?

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questions regarding boost::mem_fn and boost::bind
by Littlefield, Tyler 02 Apr '11

02 Apr '11

Hello all: I have a quick question. I was trying to learn how to use boost::mem_fn to work as a sort of function object, because I need something like this for my library. So: If I understand this correctly, it creates a function object that has () overloaded, correct? I was curious if someone could then help me figure this out, the documentation is confusing for me. lets say I have this class: class Foo { public: int Add(int a, int b) { return (a+b); } }; and I could do Foo bar; how would … [View More]

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VS2010+boost 1.44 - error in move.hpp
by archie14 02 Apr '11

02 Apr '11

While compiling the project in VS2010 previously built without errors in VS2008 I am getting following error: c:\libraries\boost\boost_1_44_0\boost\interprocess\detail\move.hpp(342): error C2440: 'return' : cannot convert from 'boost::interprocess::file_mapping' to 'boost::interprocess::file_mapping &&' You cannot bind an lvalue to an rvalue reference c:\libraries\boost\boost_1_44_0\boost\interprocess\file_mapping.hpp (62) : see reference to function template … [View More]

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[boost] [program options] Potential bug in parsing arguments where one is suffix of the other ?
by Sanjit Jhala 02 Apr '11

02 Apr '11

Hi, I have the following code (modified from example/first.cpp): *#include <boost/program_options.hpp>* *#include <string>* *#include <vector>* *#include <iostream>* * * *namespace po = boost::program_options;* * * *using namespace std;* * * *typedef vector<string> Strings;* * * *// A helper function to simplify the main part.* *template<class T>* *ostream& operator<<(ostream& os, const vector<T>& v)* *{* * copy(v.begin(), v.end(), … [View More]

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