December 2004 - Boost-users

Re: newbie build question
by Frank Brown 17 Dec '04

17 Dec '04

> > It's not the correct location. This: > > C:\Boost\include\boost-1_32\boost > > Should be: > > C:\Boost\include\boost-1_32 yes - that fixed it. many thanks! now i can move on to making coding errors! -frank

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bind and default function parameters
by Agoston Bejo 17 Dec '04

17 Dec '04

Hi! A small example: -------------------------------- template<typename T1, typename T2> bool equ(T1 t1, T2 t2, double threshold) { return t1 == t2; } int _tmain(int argc, _TCHAR* argv[]) { int ia1[] = {1,2,3,4,5}; cout << *find_if(ia1, ia1+5, bind<bool>(equ<int, int>, _1, 5)) << endl; // ERROR return 0; } ----------------------------------- Compiler: VC++7.1 (Intermezzo: another question: why do I have to specify the result type for bind in this case (bool)? Why can't it deduce it from the template function declaration: the return type is non-dependent.) Error message: c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\boost\bind.hpp(246) : error C2198: 'bool (__cdecl *)(int,int,double)' : too few arguments for call through pointer-to-function ... and the rest (I suppose they are mainly irrelevant) c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\boost\bind\bind_template.hpp(33) : see reference to function template instantiation 'R boost::_bi::list2<A1,A2>::operator ()<boost::_bi::bind_t<R,F,L>::result_type,bool(__cdecl *)(T1,T2,double),boost::_bi::list1<int &>>(boost::_bi::type<T>,F,A &)' being compiled with [ R=boost::_bi::bind_t<bool,bool (__cdecl *)(int,int,double),boost::_bi::list2<boost::_bi::list_av_2<boost::arg<1>,int >::B1,boost::_bi::list_av_2<boost::arg<1>,int>::B2>>::result_type, A1=boost::_bi::list_av_2<boost::arg<1>,int>::B1, A2=boost::_bi::list_av_2<boost::arg<1>,int>::B2, F=bool (__cdecl *)(int,int,double), L=boost::_bi::list2<boost::_bi::list_av_2<boost::arg<1>,int>::B1,boost::_bi: :list_av_2<boost::arg<1>,int>::B2>, T1=int, T2=int, T=boost::_bi::bind_t<bool,bool (__cdecl *)(int,int,double),boost::_bi::list2<boost::_bi::list_av_2<boost::arg<1>,int >::B1,boost::_bi::list_av_2<boost::arg<1>,int>::B2>>::result_type, A=boost::_bi::list1<int &> ] c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\algorithm(64) : see reference to function template instantiation 'boost::_bi::bind_t<R,F,L>::result_type boost::_bi::bind_t<R,F,L>::operator ()<int>(A1 &)' being compiled with [ R=bool, F=bool (__cdecl *)(int,int,double), L=boost::_bi::list2<boost::_bi::list_av_2<boost::arg<1>,int>::B1,boost::_bi: :list_av_2<boost::arg<1>,int>::B2>, A1=int ] d:\prog\vcpp\Boost\xBindAndDefFuncArg\xBindAndDefFuncArg.cpp(22) : see reference to function template instantiation '_InIt std::find_if<int*,boost::_bi::bind_t<R,F,L>>(_InIt,_InIt,_Pr)' being compiled with

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Re: newbie build question
by Frank Brown 17 Dec '04

17 Dec '04

D:\c\whereis>cl testBoost.cpp Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 13.10.3077 for 80x86 Copyright (C) Microsoft Corporation 1984-2002. All rights reserved. testBoost.cpp testBoost.cpp(5) : fatal error C1083: Cannot open include file: 'boost/regex.hpp': No such file or directory D:\c\whereis>set include INCLUDE=E:\Program Files\Microsoft Visual Studio .NET 2003\VC7\ATLMFC\INCLUDE;E:\Program Files\Microsoft Visual Studio .NET 2003\VC7\INCLUDE;E:\Program Files\Microsoft Visual Studio .NET 2003\VC7\PlatformSDK\include\prerelease;E:\Program Files\Microsoft Visual Studio .NET 2003\VC7\PlatformSDK\include;E:\Program Files\Microsoft Visual Studio .NET 2003\SDK\v1.1\include;C:\Program Files\Microsoft Visual Studio .NET 2003\SDK\v1.1\include\;C:\Program Files\Microsoft Visual Studio .NET\FrameworkSDK\include\;C:\Boost\include\boost-1_32\boost D:\c\whereis>dir C:\Boost\include\boost-1_32\boost\regex.hpp Volume in drive C is SYSXP Volume Serial Number is 6B12-D3A9 Directory of C:\Boost\include\boost-1_32\boost 10/04/2003 06:28 941 regex.hpp 1 File(s) 941 bytes 0 Dir(s) 472,326,144 bytes free D:\c\whereis>set BOOST_ROOT BOOST_ROOT=C:\Boost\include\boost-1_32 AFAICT the above shows the cl compiler can't find boost/regex.hpp, however the include path lists the correct location, regex.hpp shows up in a directory listing, and BOOST_ROOT is correctly set. What's going on? Something stupid perhaps. -frank brown http://www.inwa.net/~frog

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using boost with .NET CLR
by Kevin Kuo 17 Dec '04

17 Dec '04

Hi all, I'm not very familar with microsoft .net technologies, but I would like to know if anyone has been able to use boost inside a managed c++ application? Are there some performance hits, pitfalls, or is it in general a bad idea? Thanks. Kevin

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boost and memory allocations (signals and others)
by Frank Maddin 16 Dec '04

16 Dec '04

We've been thinking about using certain boost functionality on a project. We were trying to keep the number of allocations down. An engineer did some testing on signals and their usage of memory and found that there was a surprising number of allocation related things were happening. Even sending a signal did allocation ops. If developers want to reduce allocation overhead, do they use memory pools or some other solution? Is there a pattern of large numbers of small allocations across the lib? For things like the boost's smart pointers also? Below is a description of the test. Thanks, -fm ------------ Memory Usage I ran a simple test to see how much memory is being used struct Hello { void operator (int year) { printf("Year = %d\n",year); } }; void Test () { Hello hello; boost::signal< void(int) > sig; sig.connect( hello ); sig( 1968 ); } Note: I used _CrtSetAllocHook to monitor the memory usage... Results: sizeof( sig ) = 24 bytes but the default constructor does a surprising amount of dynamic allocation (for an empty list) calls malloc or free 51 times allocates 277 bytes in 13 blocks (not including heap overhead) so the actual size is more like 24 + 277 + 13*8 = 405 byes a call to connect does 26 alloc-operations... resulting in 133 bytes in 8 blocks a call to send a signal does 78 alloc-operations... resulting in 0 bytes in 0 blocks ... My tests were debug builds... but I looked at the calls and the library just calls new a lot... there seems to be a pattern of having empty wrapper classes where the constructor dynamically allocates the actual implementation...

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Tuple access on Solaris
by darren.gilbert＠ubs.com 16 Dec '04

16 Dec '04

Hello, I was using the boost tuples library (from boost 1.31) to create a cache key. However, the Solaris compiler (SUNWspro v6.2.p1) complained when I tried to access the last element in the tuple. My class looked something like this: typedef enum result_type_id { ... } ResultTypeID; class ParamStateKey; class Cache { typedef boost::tuple<ParamStateKey, ResultTypeID, int, int, int> key_type; // cache implementation ... // some helper functions defined to hide the boost::tuple interface static ParamStateKey &GetState(key_type &k) { return boost::tuples::get<0>(k); } static ResultTypeID &GetGreek(key_type &k) { return boost::tuples::get<1>(k); } static int &GetProduct(key_type &k) { return boost::tuples::get<2>(k); } static int &GetSubpage(key_type &k) { return boost::tuples::get<3>(k); } static int &GetBucket(key_type &k) { return boost::tuples::get<4>(k); } static key_type MakeKey(const ParamStateKey &psk, ResultTypeID r, int p1, int p2, int bkt) { return boost::tuples::make_tuple(psk, r, p1, p2, bkt); } }; The solaris compiler complained whenever I tried to call Cache::GetBucket() with the following error: "../../../../incl/3rd/boost/tuple/detail/tuple_basic.hpp", line 105: Error: Could not find a match for boost::tuples::detail::get_class<0>::get<boost::tuples::detail::get_class<0>::RET, boost::tuples::detail::get_class<0>::HT, boost::tuples::detail::get_class<0>::TT>(boost::tuples::cons<int, boost::tuples::null_type>). "../../../../incl/3rd/boost/tuple/detail/tuple_basic.hpp", line 105: Where: While instantiating "static boost::tuples::detail::get_class<1>::get<int&, int, boost::tuples::cons<int, boost::tuples::null_type>>(boost::tuples::cons<int, boost::tuples::cons<int, boost::tuples::null_type>>&)". "../../../../incl/3rd/boost/tuple/detail/tuple_basic.hpp", line 105: Where: Instantiated from non-template code. Firstly, I have no way of deciphering that error message. Through trial and error, I found that removing the GetBucket() calls solved the problem. However, I needed these calls. I reasoned that since the other helper functions worked, it was a problem accessing the last element of the tuple. So I created a dummy entry in the tuple and redefined my typedef: typedef boost::tuple<ParamStateKey, ResultTypeID, int, int, int, int> key_type; This work-around is fine, so this is not an urgent problem. But it seems like this should not be necessary. ________________________________________ Darren Gilbert Associate Director UBS - Equities Quantitative Strategies Phone: +1 (312) 525-5766 Stein's law: "When a trend cannot continue it will stop." -- Herb Stein, Chairman of the Council of Economic Advisors under Nixon Visit our website at http://www.ubs.com This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. E-mail transmission cannot be guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses. The sender therefore does not accept liability for any errors or omissions in the contents of this message which arise as a result of e-mail transmission. If verification is required please request a hard-copy version. This message is provided for informational purposes and should not be construed as a solicitation or offer to buy or sell any securities or related financial instruments.

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a simple question from a green hand
by Gump Xu 16 Dec '04

16 Dec '04

Hi, there. I am a new user of Boost lib. I have a simple question about installation. I've download and unpacked boost-1.32.0 to my Linux box. When I followed the instruction in "Get Started" to install Boost, I found there was no such a "bjam" binary file in my ~/boost_1_32_0 directory. Can anybody help me out? Thank you.

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scoped_ptr has no release function
by gast128 16 Dec '04

16 Dec '04

Dear all, Probably there will be a good rationale for this, but the scoped_ptr has no release fct. No we have to use the auto_ptr, with all its drawbacks. Does anyone know the reason for this? Wkr, me

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BGL + VC7: no bundled properties because of BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
by Dan Dimerman 16 Dec '04

16 Dec '04

Hello, Failing to do it by myself, I ask for the group's help to fully understand why I can't use BGL's bundled properties with MS VC7. I traced the impediment to the fact that in the configuration header "visualc.hpp" the constant BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION is #defined. This, further on (properties.hpp), causes the BOOST_GRAPH_NO_BUNDLED_PROPERTIES to be #defined. My question is, what is in this context understood by "template partial specialization" ? I ask, because I'm almost sure I've used this feature in VC7 before, hence my confusion. Many thanks in advance... Dan

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[BGL] Obtaining corresponding vertex_descriptors
by J Swan 16 Dec '04

16 Dec '04

Suppose we have two BGL graphs g1 and g2, of type Graph1 and Graph2 respectively, such that g2 is a copy of g1. Given a vertex_descriptor v1 belonging to g1, can one generically obtain the corresponding vertex descriptor for g2: a) if Graph1 and Graph2 are actually the same type b) if Graph1 and Graph2 are different types? Regards, Jerry.

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