May 2008 - Boost-users - lists.boost.org

how to list files and folder names Boost way ?
by Meir Yanovich 16 May '08

16 May '08

Hello all i like to get all folder and files names under giving folder , what will be the optimized way ( if any ) that boost can offer can you point me to example code thanks

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Re: [Boost-users] PROBLEM SOLVED: Problem compiling against boost on AIX using xlC
by Rich Cook 15 May '08

15 May '08

On May 15, 2008, at 2:14 PM, K. Noel Belcourt wrote: > Hi Rich, > > On May 14, 2008, at 6:35 PM, Rich Cook wrote: > >> I have a need to try to compile boost_1_35_0 using xlC. I am getting >> the following error from my attempt, and I cannot find anything on >> google about it. Is there an environment variable or compiler flag I >> ought to be using with boost? > > Optional in 1.35 seems to work okay for me with xlC version 8.0. > Here's the code I tested. > > > xlC -g test.C -I/sierra/Release/Boost/1.35.0 > "test.C", line 11.12: 1540-1102 (W) "p" might be used before it is > set. > > So it doesn't appear that any macros or compile options need to be > set for this to compile. Thank you for mentioning the version. It appears that our xlC was by default 7.0, but we have 8.0 as well and it worked perfectly as you said. Thanks! -- ✐Richard Cook ✇ Lawrence Livermore National Laboratory Bldg-453 Rm-4037, Mail Stop L-557 7000 East Avenue, Livermore, CA, 94550, USA ☎ (office) (925) 423-9605 ☎ (fax) (925) 423-6961 --- Information Management & Graphics Grp., Services & Development Div., Integrated Computing & Communications Dept. (opinions expressed herein are mine and not those of LLNL)

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[Units] another system problems
by Patricia Hawley 15 May '08

15 May '08

Hi, I used a previous version of the Units library to sketch out a fps system (foot-pound-second) that paralleled the cgs system, and the code compiled and ran fine. I am now returning to this effort, and I want to wrap it into a coordinate transform package, but I can no longer get the code to compile. I am using the latest code from the Boost sandbox, and MS Visual Studio with WinXP. The problem appears to be in the conversions, but I don't see what is missing when compared to cgs. typedef unit<length_dimension, SI::system > my_unit; typedef quantity< my_unit, ofs::Real64 > linear_measure; linear_measure dummy(200.0*CGS::centimeter); // implicit conversion from SI::meter to CGS::centimeter linear_measure dummy2(200.0*FPS::foot); The first three lines work fine, but the last one generates 10 errors with my compiler (MSVC 8.0). The first error is boost/units/detail/conversion_impl.hpp(342) : error C2039: 'type' : is not a member of 'boost::units::detail::call_base_unit_converter<Source,Dest>' with [ Source=boost::units::foot_base_unit, Dest=boost::units::unit<boost::units::length_dimension,boost::units::heterogeneous_system<boost::units::heterogeneous_system_pair<boost::units::dimension_list<boost::units::heterogeneous_system_dim<boost::units::meter_base_unit,boost::units::static_rational<1>>,boost::units::dimensionless_type>,boost::units::length_dimension>>> ] boost/units/detail/conversion_impl.hpp(536) : see reference to class template instantiation 'boost::units::detail::conversion_impl<N>::apply<Begin,DestinationSystem>' being compiled with [ N=1, Begin=boost::units::dimension_list<boost::units::heterogeneous_system_dim<boost::units::foot_base_unit,boost::units::static_rational<1>>,boost::units::dimensionless_type>, DestinationSystem=boost::units::homogeneous_system<boost::units::dimension_list<boost::units::meter_base_unit,boost::units::dimensionless_type>> ] boost/units/detail/conversion_impl.hpp(216) : see reference to class template instantiation 'boost::units::detail::conversion_factor_helper<Source,Dest>' being compiled with [ Source=boost::units::unit<boost::units::length_dimension,boost::units::heterogeneous_system<boost::units::heterogeneous_system_pair<boost::units::dimension_list<boost::units::heterogeneous_system_dim<boost::units::foot_base_unit,boost::units::static_rational<1>>,boost::units::dimensionless_type>,boost::units::length_dimension>>>, Dest=boost::units::unit<boost::units::length_dimension,boost::units::heterogeneous_system<boost::units::heterogeneous_system_pair<boost::units::dimension_list<boost::units::heterogeneous_system_dim<boost::units::meter_base_unit,boost::units::static_rational<1>>,boost::units::dimensionless_type>,boost::units::length_dimension>>> ] boost/units/detail/conversion_impl.hpp(324) : see reference to class template instantiation 'boost::units::detail::call_base_unit_converter_base_unit_impl<false,false>::apply<Source,Dest>' being compiled with [ Source=boost::units::foot_base_unit, Dest=boost::units::meter_base_unit ] boost/units/detail/conversion_impl.hpp(342) : see reference to class template instantiation 'boost::units::detail::call_base_unit_converter<Source,Dest>' being compiled with [ Source=boost::units::foot_base_unit, Dest=boost::units::unit<boost::units::length_dimension,boost::units::heterogeneous_system<boost::units::heterogeneous_system_pair<boost::units::dimension_list<boost::units::heterogeneous_system_dim<boost::units::meter_base_unit,boost::units::static_rational<1>>,boost::units::dimensionless_type>,boost::units::length_dimension>>> ] boost/units/detail/conversion_impl.hpp(377) : see reference to class template instantiation 'boost::units::detail::conversion_impl<N>::apply<Begin,DestinationSystem>' being compiled with [ N=1, Begin=boost::units::dimension_list<boost::units::heterogeneous_system_dim<boost::units::foot_base_unit,boost::units::static_rational<1>>,boost::units::dimensionless_type>, DestinationSystem=boost::units::homogeneous_system<boost::units::dimension_list<boost::units::meter_base_unit,boost::units::dimension_list<boost::units::scaled_base_unit<boost::units::gram_base_unit,boost::units::scale<10,boost::units::static_rational<3>>>,boost::units::dimension_list<boost::units::second_base_unit,boost::units::dimension_list<boost::units::ampere_base_unit,boost::units::dimension_list<boost::units::kelvin_base_unit,boost::units::dimension_list<boost::units::mole_base_unit,boost::units::dimension_list<boost::units::candela_base_unit,boost::units::dimension_list<boost::units::radian_base_unit,boost::units::dimension_list<boost::units::steradian_base_unit,boost::units::dimensionless_type>>>>>>>>>> ] boost/units/detail/conversion_impl.hpp(372) : while compiling class template member function 'boost::units::quantity<Unit,Y> boost::units::conversion_helper<From,To>::convert(const boost::units::quantity<boost::units::unit<Dim,System>,Y> &)' with [ Unit=my_unit, Y=ofs::Real64, From=boost::units::quantity<boost::units::unit<boost::units::length_dimension,boost::units::FPS::system>,double>, To=boost::units::quantity<my_unit,ofs::Real64>, Dim=boost::units::length_dimension, System=boost::units::FPS::system ] boost/units/quantity.hpp(167) : see reference to class template instantiation 'boost::units::conversion_helper<From,To>' being compiled with [ From=boost::units::quantity<boost::units::unit<boost::units::length_dimension,boost::units::FPS::system>,double>, To=boost::units::quantity<my_unit,ofs::Real64> ] testQuantifiedVector.cpp(47) : see reference to function template instantiation 'boost::units::quantity<Unit,Y>::quantity<boost::units::unit<Dim,System>,double>(const boost::units::quantity<boost::units::unit<Dim,System>,Y> &,void *)' being compiled with [ Unit=my_unit, Y=ofs::Real64, Dim=boost::units::length_dimension, System=boost::units::FPS::system ] Any guidance in this would be greatly appreciated. Pat

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math function: tabulated data
by Hicham Mouline 15 May '08

15 May '08

Hello, I am modeling a 1-dim real numerical function f, not necessarily monotone, described by : x0 y0 x1 y1 . xn-1 yn-1 by template <typename InterpolationType, typename ExtrapolationType, typename IntegrationType> class Curve : public std::map<double, double> { protected: Curve(); virtual ~Curve(); const InterpolationType& interpolator() const; const ExtrapolationType& extrapolator() const; const IntegrationType& integrator() const; double operator()(double t) const; /**< read f(t) */ double& operator()(double t); /**< write f(t)=ft */ double inverse(double f) const; /**< read f-1(f) */ double derivative(double t) const; /**< read f'(t) */ /** * \brief Returns Integral over [tmin,tmax] of f(t) using * the template argument integration method */ double integral(double tmax, double tmin =0.0) const; /** * \brief Returns Integral over [tmin,tmax] of f^n(t) using * the template argument integration method */ double integral(int n, double tmax, double tmin =0.0) const; /** * \brief Applies operation Op on the f(t) curve, outputs in result */ template<typename Op> void transform(Curve& result) const; /** * \brief Outputs tabulated data */ friend std::ostream& operator<<(std::ostream& s, const Curve& rhs); private: const InterpolationType& interpolator_; const ExtrapolationType& extrapolator_; const IntegrationType& integrator_; }; There are different ways of interpolating f(x) for x0 <= x <= xn-1, extrapolating f(x) for x<x0 or x>xn-1, and integrating over some domain [tmin,tmax] 1- Each of InterpolationType, ExtrapolationType, IntegrationType arguments expects a type derived from BaseInterpolator, BaseExtrapolator, BaseIntegrator, but I am not certain I need this inheritance. What are the tradeoffs? 2- Curve is an internal implementation object of my library. However, private derived classes from Curve will be exposed to library users. So Curve's header will have to be exposed too. I guess public inheritance from map is fine? There are no public constructors. 3- Constructing the curve is not performance-critical, but the operator(), inverse, derivative and integral are. I have played with native arrays, with map and with boost::multi_array with optimized macros, and it seems operator() when it is a simple linear interpolation is fastest with maps (because they are sorted). Any comments? Rds,

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first day on boost
by Longyu Mei 15 May '08

15 May '08

First question on boost. Just downloaded the boost library. I am going to use it on Windows right now. Do I need to build it before I can use it? or I can include all its source files into my project to get my project built? If I need to build it, can I use Cygwin g++ to build it or I have to use Microsoft compiler to do it? thanks, James

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lexical_cast with tuple target fails.
by Bryan Green 15 May '08

15 May '08

Should it be possible to do a lexical_cast to a tuple if tuple_io.hpp is included? It turns out that it doesn't work. The following example will throw bad_lexical_cast: #include <boost/tuple/tuple.hpp> #include <boost/tuple/tuple_io.hpp> #include <boost/lexical_cast.hpp> #include <iostream> #include <sstream> #include <string> using namespace std; typedef boost::tuple<unsigned,unsigned,unsigned> point; int main() { string s = "(1 2 3)"; point p; stringstream iss; if (!(iss << s).fail()) { if (iss >> p && iss.get() == char_traits<char>::eof()) cout << p << endl; } // throws here: p = boost::lexical_cast<point>(s); cout << p << endl; return 0; }

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Re: [Boost-users] boost::result_of error?
by Hicham Mouline 15 May '08

15 May '08

But "floatfct" was defined earlier as the type of a pointer to a function with only 1 arg float.just passing the template argument to result_of creates a new type?is the new type also called floatfct ? ----- Original Message ----- From: "Ovanes Markarian" To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] boost::result_of error? Date: Thu, 1 May 2008 13:58:21 +0200 Hicham, as far as I understand your code you pass to result_of a new type: typedef typename boost::result_of<floatfct(float, float)>::type resultype; This type is a pointer to a function type, which has as return type a pointer to floatfct and as params float, float. That's why it compiles. Regards, Ovanes On Thu, May 1, 2008 at 1:25 PM, Hicham Mouline <hicham(a)mouline.org> wrote: Hello, trying out Pete Becker's "c++ std lib ext" exercises, ex1 p155 #include <iostream> #include <typeinfo> #include <boost/utility/result_of.hpp> typedef float (*floatfct)(float); int main(int argc, char* argv[]) { typedef typename boost::result_of<floatfct(float, float)>::type resultype; std::cout<< typeid(resultype).name() << std::endl; } should fail, because result_of is instantiated with a callable type with 2 float args, while it's been defined as taking 1 float arg only? with intel10.1-MSVC8-boost1.35, it links. rds, _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Assigning 'this' to share_ptr
by Abdo Haji-Ali 15 May '08

15 May '08

Hi, I was recently introduced to boost's shared_ptr and I really liked the fact that freeing memory is done automatically. So I started using it in almost every case, instead of the dangerous C-style pointers. However, I'm having a design issue concerning shared_ptr. Here's a snippet that describes my situation: <code> #include <boost/shared_ptr.hpp> class MyClass; typedef boost::shared_ptr<MyClass> MyClassPtr; class MyClass { public: // Fields virtual void CallUtility(); // May be overrided later static MyClassPtr CreateMyClass() { return MyClassPtr(new MyClass()); } private: MyClass(); }; void UtilityFunc(MyClassPtr pClass) { // Do things with pClass } void MyClass::CallUtility() { // Do stuff // How can I pass 'this' to UtilityFunc? // without freeing it, of course UtilityFunc(MyClassPtr(this)); // How can I pass 'this' to UtilityFunc? // Do stuff } </code> Note that MyClass is always created using 'new' on the heap (never on the stack). Also note that a function is not my only case. I also have classes that store a MyClassPtr and there's a function in MyClass that does something like this: ClassA MyClass::CreateClassA() { ClassA a; a.myClass = this; // How can I do this return a; } One way to solve this would be to pass a MyClassPtr parameter to the CallUtility(), and then use it instead of this. So it becomes like this: pMyClass->CallUtility(pMyClass); Which is ugly, to say the least. Do you have another way? Am I missing something trivial here? -- Abdo Haji-Ali Programmer In|Framez

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in-memory stream, binary archive,serialization
by Victor Whiskey Yankee 15 May '08

15 May '08

Hello, I need to serialize into and from a memory buffer using boost::archive::binary_oarchive and binary_iarchive. Using std::stringstream does not work (it does work with text_oarchive and text_iarchive in memory and using files). I found a mention in the archives about similar need here: http://lists.boost.org/boost-users/2007/10/31580.php But I cannot figure it out. I am trying to flesh out the two operations marshall() and unmarshall() below, such that an instance of STORAGE_TYPE will hold the resulting bytes of an archival operation of a class of type T, or the inverse where I have the STORAGE_TYPE and want to create a new T from an oarchive operation. #include <string> #include <vector> #include <sstream> #ifdef USE_TEXT typedef std::string STORAGE_TYPE; #else typedef std::vector<unsigned char> STORAGE_TYPE; #endif template<typename T> void marshall(const T& storeObj, STORAGE_TYPE& store) { } and it's compliment: template<typename T> void unmarshall(T& restoredObj, const STORAGE_TYPE& store) { } Help getting the STORAGE_TYPE and memory stream would be greatly appreciated. Thanks, Vic

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Compile errors in Boost files, suspect GCC version problem
by jadooo 15 May '08

15 May '08

Hi, I am trying to port my linux application which used the Boost library to windows using cygwin. When i tried to compile I am getting the following errors ../Thread/pasync.cxx:1: warning: -fPIC ignored for target (all code is position independent) ../Thread/patomic.cxx:1: warning: -fPIC ignored for target (all code is position independent) ../Thread/pmsgq.cxx:1: warning: -fPIC ignored for target (all code is position independent) ../Thread/pmtxtable.cxx:1: warning: -fPIC ignored for target (all code is position independent) ../Thread/prwlock.cxx:1: warning: -fPIC ignored for target (all code is position independent) ../Thread/psemaphore.cxx:1: warning: -fPIC ignored for target (all code is position independent) ../Thread/pthread.cxx:1: warning: -fPIC ignored for target (all code is position independent) ../../boost_1_33_1/boost/shared_ptr.hpp: In member function `T* boost::shared_ptr<T>::operator->() const [with T = LCEllaLogSource]': ../include/Shutdown.h:263: instantiated from here ../../boost_1_33_1/boost/shared_ptr.hpp:253: error: `assert' undeclared (first use this function) ../../boost_1_33_1/boost/shared_ptr.hpp:253: error: (Each undeclared identifier is reported only once for each function it appears in.) ../../boost_1_33_1/boost/shared_ptr.hpp: In member function `T* boost::shared_ptr<T>::operator->() const [with T = linx::LCShutdownObserver]': ../include/SubjectObserver.h:344: instantiated from `void GenericSubject<T1, T2>::Notify(T2&) [with T1 = linx::LCShutdownObserver, T2 = linx::LCShutdownMessage]' ../include/Shutdown.h:176: instantiated from here ../../boost_1_33_1/boost/shared_ptr.hpp:253: error: `assert' undeclared (first use this function) ../../boost_1_33_1/boost/shared_ptr.hpp: In member function `T* boost::shared_ptr<T>::operator->() const [with T = LCLogHandler<logging::LogType>]': ../include/LoggerClasses.h:274: instantiated from `bool LCLogSource<T>::SendLogMessage(T, LCLogMessage&) [with T = logging::LogType]' ../include/Shutdown.h:263: instantiated from here ../../boost_1_33_1/boost/shared_ptr.hpp:253: error: `assert' undeclared (first use this function) ../../boost_1_33_1/boost/shared_ptr.hpp: In member function `T* boost::shared_ptr<T>::operator->() const [with T = LCLogObserver]': ../include/SubjectObserver.h:344: instantiated from `void GenericSubject<T1, T2>::Notify(T2&) [with T1 = LCLogObserver, T2 = LCLogMessage]' ../include/LoggerClasses.h:275: instantiated from `bool LCLogSource<T>::SendLogMessage(T, LCLogMessage&) [with T = logging::LogType]' ../include/Shutdown.h:263: instantiated from here ../../boost_1_33_1/boost/shared_ptr.hpp:253: error: `assert' undeclared (first use this function) make: *** [Thread/pthread.o] Error 1 I am using boost provided with cygwin that is boost_1_33_1 and GCC which is 3.4.4. I have build the same application in my Ubuntu machine where GCC is 4.1.3. I am trying to upgrade GCC to some latest versions, but as of now I have not yet succeeded. Just wanted to know if it is really a problem with the compiler or it is some other problem It's being 2 days now I am looking into this issue, any help wil be highly appreciable.. With regards -- View this message in context: http://www.nabble.com/Compile-errors-in-Boost-files%2C-suspect-GCC-version-… Sent from the Boost - Users mailing list archive at Nabble.com.

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