- Boost-users - lists.boost.org

Re: [Boost-users] return type of boost::bind
by Cheenu Srinivasan 02 Feb '04

02 Feb '04

[Reposting under corect subject.] Peter Dimov wrote: >Cheenu Srinivasan wrote: > > > > With MSVC 7.1. the exception is thrown with both 'bound_func = > > bind(...)' and 'bound_func(bind(...))'. But I tried it with > > g++/solaris and it works. So it does look like a bug with the MS > > compiler. Thanks. > >It works for me in MSVC 7.1, but I'm using the CVS version of Boost. It may >be a bug in 1.30.2 (if that's what you are using). You may download 1.31 >release candidate 2 from > > http://www.esva.net/~beman/boost_1_31_0_rc2.zip > >to verify that the problem does not occur with the immininent 1.31 release. I tried VisualStudio 7.1 with boost_1_31_0_rc2 with the same results: a bad_function_call exception. I tried it on two different PCs (same version of VisualStudio, of course). _________________________________________________________________ Let the new MSN Premium Internet Software make the most of your high-speed experience. http://join.msn.com/?pgmarket=en-us&page=byoa/prem&ST=1

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cannot compile boost with dev-cpp 4.9.8.0
by Vikrant Rathore 02 Feb '04

02 Feb '04

HI, Anyone has compiled boost library successfully using dev-cpp the new version. I try compiling it and it gives many errors. I follow the following qway to compile: C:\projects\boost> C:\projects\boost>set path=c:\dev-cpp\bin C:\projects\boost>set MINGW_ROOT_DIRECTORY=c:\dev-cpp C:\projects\boost>set MINGW_BIN_DIRECTORY=c:\dev-cpp\bin C:\projects\boost>set MINGW_INCLUDE_DIRECTORY=c:\dev-cpp\include C:\projects\boost>set MINGW_STDLIB_DIRECTORY=c:\dev-cpp\lib C:\projects\boost>bjam -sTOOLS=mingw I tried many different option including usig MSYS with no luck. Thanks with best regards, Vikrant

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Compliation speed of Boost.Signal in C++ Builder 5
by Ben Chan 02 Feb '04

02 Feb '04

Dear All, I'm new to boost and trying to use boost.signal in my BCB 5.0 project,everything works fine except my project compilation speed was horribly slow down.Once I included the <signal.hpp>,the compiler have to compile extra thousands line of code even my project is empty.I did put the signal.hpp file in my pre-compiled header and include the static lib, but seems it can't help much. Any suggestion to improve the compliation speed in BCB?VC7.0 seems compile pretty fast. Thx Ben _________________________________________________________________ Linguaphone : Learning English? Get Japanese lessons for FREE http://go.msnserver.com/HK/30476.asp

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Re: [Boost-users] return type of boost::bind
by Cheenu Srinivasan 01 Feb '04

01 Feb '04

Peter Dimov wrote: > Cheenu Srinivasan wrote: > > Duane Murphy wrote: > >> The return type of boost::bind is fairly indeterminate. In order to > >> call a bound function at a later time, look at boost::function. It > >> does a nice job of holding on to a function that uses boost::bind. > > > > I looked at "Using bind with Boost.Function" in the boost::function > > docs. Mimicing that, for my example, I tried: > > > > boost::function<double (int)> bound_func = boost::bind(f, _1, 1.234); > > int i = 99; > > cout << bound_func(i) << endl; > > > > but it throws a bad_function_call exception when bound_func(i) is > > invoked. How do I use boost::function for this situation? > > Works for me; it's probably a compiler bug. Which compiler are you using? > > Try > > boost::function<double (int)> bound_func( boost::bind(f, _1, 1.234) ); > > instead. With MSVC 7.1. the exception is thrown with both 'bound_func = bind(...)' and 'bound_func(bind(...))'. But I tried it with g++/solaris and it works. So it does look like a bug with the MS compiler. Thanks.

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return type of boost::bind
by Cheenu Srinivasan 01 Feb '04

01 Feb '04

I wish to store the return value of boost::bind in an intermediate object to invoke it at a later time. I only ever see examples which combine the call to boost:bind with the immediate invocation on the returned object such as: #include <boost/bind.hpp> using namespace boost; #include <iostream> using namespace std; double f(int i, double d) { cout << "int = " << i << endl; return d; } main() { int i = 99; cout << bind(f, _1, 1.234)(i) << endl; } Instead I'd like to postpone the call to the returned object. What's the type of obj? main() { int i = 99; WHAT_IS_MY_TYPE obj = bind(f, _1, 1.234); ... cout << obj(i) << endl; } Thanks, Cheenu _________________________________________________________________ What are the 5 hot job markets for 2004? Click here to find out. http://msn.careerbuilder.com/Custom/MSN/CareerAdvice/WPI_WhereWillWeFindJob…

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Problems with boost build setup
by Michael Buksas 31 Jan '04

31 Jan '04

Hi all, I'm having newbie problems with linking against Boost libraries. Here's the situation: I can build the boost libraries without problem, and I'm using the default toolkit for my system, (Fedora Core 1) which is g++. Compiling is no problem, just linking. I can link the object files by hand, but not as part of using Boost.build. As a test, I grabbed an example program from the date_time library and it's corresponding build rule. This code compiles fine as part of Boost, but if I move it to my project space, I get linking errors. Here's my Jamfile: exe time_math : <lib>$(BOOST_ROOT)/build/boost_date_time time_math.cpp : <include>$(BOOST_ROOT) <define>BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG ; and here's my Jamrules in the same directory: project-root ; path-global BOOST_ROOT : "/opt/boost-1.30.2" ; Here's the Jamfile from /opt/boost-1.30.2/libs/date_time/example/ exe time_math : <lib>../build/boost_date_time posix_time/time_math.cpp : <include>$(BOOST_ROOT) <define>BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG ; And the environment variable is set: BOOST_BUILD_PATH=/opt/boost-1.30.2/tools/build When I run bjam from a clean build, here's what I get: gcc-C++-action bin/time_math/gcc/debug/runtime-link-dynamic/time_math.o gcc-Link-action bin/time_math/gcc/debug/runtime-link-dynamic/time_math bin/time_math/gcc/debug/runtime-link-dynamic/time_math.o(.gnu.linkonce.t._ZN5boost9date_time15month_formatterINS_9gregorian10greg_monthENS0_13simple_formatEE12format_monthERKS3_RSo+0x3a): In function `boost::date_time::month_formatter<boost::gregorian::greg_month, << edited for brevity >> In function `boost::date_time::month_formatter<boost::gregorian::greg_month, << edited for brevity >> collect2: ld returned 1 exit status export LD_LIBRARY_PATH g++ -g -o "bin/time_math/gcc/debug/runtime-link-dynamic/time_math" "bin/time_math/gcc/debug/runtime-link-dynamic/time_math.o" -Wl,-rpath-link,. ...failed gcc-Link-action bin/time_math/gcc/debug/runtime-link-dynamic/time_math... ...failed updating 1 target... So things are compiling, but not linking. I must not have the configuration for Boost.build correct, but I've tried everything I can think of. Any help would be appreciated. Thanks, Mike Buksas -- Michael Buksas -- michael(a)buksas.net -- www.buksas.net

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Properties in a subgraph
by Hugues Joly 30 Jan '04

30 Jan '04

Hi, I'd like to clarify a point about the graph properties accessed through a subgraph. According to the documentation of get(PropertyTag, subgraph& g): vertex and edge properties are shared by all subgraphs, so changes to a property through a local vertex descriptor for one subgraph will change the property for the global vertex descriptor, and therefore for all other subgraphs (c.f. boost-1.30.2/libs/graph/doc/subgraph.html). Here, I'm sending you a small program inspired by the boost-1.30.2/libs/graph/example/subgraph.cpp example. >From its behavior, it seems that: 1) A property value is not shared between the global descriptor and its corresponding local descriptors. 2) we need to initialize property values for each of the subgraphs. For example, if I set a name "A" for the global vertex descriptor A, that property is not seen through the corresponding local vertex descriptors. Is this a case of misuse or is it a bug? __________________________________________________________ Lèche-vitrine ou lèche-écran ? magasinage.yahoo.ca

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Re: [Boost-users] Using boost::format with Lambda expressions
by Shawn Church 29 Jan '04

29 Jan '04

Jaakko Jarvi (jajarvi(a)cs.indiana.edu) wrote: > Lambda and format don't play well together, I noticed :( > Here's a code that works however, with some explanation. > Not pretty. > > Best, Jaakko > ... > format f("%-10s|") ; > for_each(Foos.begin(), Foos.end(), > cout << ret<format&>(var(f) % bind(&foo::name, _1))); > > } > > // format defines operator% as a member, which takes precedence over > // % defined by lambda. Therefore one must make the format object to > // be a lambda functor. var does that. > // Var, however, cannot take a temporary object (it holds a reference to > // the wrapped object). That's why the variable f. > // ret<format&> informs lambda about the return type of formats % operator. OK, that is just what I was looking for, thanks!!! I tried all of those things but not in the right combination. Is there any resources (i.e. example programs or additional documentation) available for the lambda library. I have read through the test code already. Thanks,

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Using boost::format with Lambda expressions
by Shawn Church 29 Jan '04

29 Jan '04

I may be missing something simple here but I have tried everything I can think of and cannot get the following to work (simplified from a project I am working on): Given a class such as: class foo{ public: foo(const char* name): _name(name) {} const char* name() const {return _name.c_str();} private: std::string _name;}; I can do the following without any problems: std::vector<foo> Foos; ... for_each(Foos.begin(), Foos.end(),cout << bind(&foo::name, _1) << "|"); This prints a list of all the names in the vector of Foo objects by calling the Foo::name() method. It would be nice to be able to do something like the following: for_each(Foos.begin(), Foos.end(), cout << format("%-10s|") % bind(&foo::name, _1); I have tried everything I can think of including extending the return type deduction of the lambda library to include the "%" operator as used by format and binding directly to the basic_format::operator% method. In every case I get 40 or so compile errors explaining why my 30 character statement is wrong :-) Does anyone have an example of this usage that works? This is not a high priority as I can obviously just format the value returned by the Foo::name() method but it would be nice to have this technique available when the need arises. I adapated the code above from a test program that demonstrates the problem in detail. I can provide the test program if anyone is interested (just tell me what to do with it). Thankyou for any help you can provide, Shawn Church sl_church(a)sbc_global.net

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Storing vertex objects and edge objects in a BGL graph?
by Hugues Joly 29 Jan '04

29 Jan '04

Hi, I'd like to know if it's possible to create a BGL graph that uses custom-made classes for the nodes and the edges. While looking to your documentation, I came across the following: "Many graph representations (such as adjacency lists) do not store actual vertex objects, while others do (e.g., pointer-linked graphs)." (c.f. boost-1.30.2/libs/graph/doc/quick_tour.html) Is the pointer-linked graph implementation supplied from boost or do I have to create one and use external adaptation for using it with your library? Thanks in advance. __________________________________________________________ Lèche-vitrine ou lèche-écran ? magasinage.yahoo.ca

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