- Boost-users - lists.boost.org

generic factory creator
by Stephen torri 04 Sep '04

04 Sep '04

In my example data is passed between objects using a Data_Source. I want to hide the method data is passed from what the value is of the data. So a object receiving it does not need to be concerned with whether the data is coming from a file or database. In my situation I have three data sources for information: a file, memory pointer or database. Each of these data sources can handle a std::string, a Memory_Object, and a Graph_Object type as its internal data structure. The question I want to understand is how to create a generic interface to create the appropriate factory. Here is the table of the possible data source combinations (3 types * 3 sources = 9 possible). So more types and more sources can make creating the right Data_Source an ugly experience for maintaining the code. I don't want to have to have 9 separate functions. ----------------------------------------------------------- | File_Data_Src | Memory_Data_Src | Graph_Data_Src ----------------------------------------------------------------------- std::string | x | x | x ------------------------------------------------------------------------ Memory Obj | x | x | x ------------------------------------------------------------------------ Graph Obj | x | x | x ------------------------------------------------------------------------ At initialization I give a interger the Data_Source_Factory_Creator to represent what kind of factory I want. When a call is made to the Data_Source_Factory_Creator::get_Factory I want the apporpriate factory returned based upon the integer value given during initialization. Right now I get the right compilor error for Data_Source_Factory_Creator::get_Factory() because given Data_Source_Factory is a template class I need to instantiate this template correctly. I don't know how to make this function return a generic type so that I can do: Data_Source_Factory<File_Data_Source>* m_factory = Data_Source_Factory_Creator::get_Factory(); Any ideas? Stephen -- Email: storri(a)torri.org

1 0

Signals - last call
by Georgios Diamantopoulos 04 Sep '04

04 Sep '04

Hello everyone, I have a question concerning signals. I wanted to force one of the callbacks to be called last. Obviously this needs to be done in an agnostic way since the calling function will probably not know how many other callbacks are connected and so on. I could not find anything in the documentation - only about numbered calls. Any ideas? Thanks in advance. Georgios

2 1

Is there a binary serialization class ?
by Raj 03 Sep '04

03 Sep '04

Hi, Is there a binary serialization class in any of the boost file lib ? Also, how do I re-target and compile the boost libraries with the newly released Visual Studio Express edition ( VC 8.0 ) ? Thank in advance. Raja

9 14

How to find min-cut?
by Daniele Carlucci 03 Sep '04

03 Sep '04

Hi, How can I find the min-cut (max-flow) in a graph undirected with all the weights of the edges equal one. Thanks Daniele

1 0

Building boost as part of larger project which also uses jam
by Phillip Seaver 03 Sep '04

03 Sep '04

I want to switch to jam for building our projects and I was wondering how to handle building boost within those projects. Will "subinclude boost" from the directory above it work? Or will I have to use bjam on the boost tree (like a recursive make)? Thanks in advance, Phillip

3 3

RE: [Boost-users] statically linking to Boost.Threads with msvc7
by Simmons, Aaron 03 Sep '04

03 Sep '04

Oh... The error message is not exactly straight-forward. I thought something was broken. Shouldn't the Boost.Threads documentation mention this? Such as in the FAQ? It would've saved me quite a bit of time... -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Ben Hutchings Sent: Friday, September 03, 2004 9:48 AM To: boost-users(a)lists.boost.org Subject: RE: [Boost-users] statically linking to Boost.Threads with msvc7 Aaron Simmons <a-simmons1(a)ti.com> wrote: I've built and installed boost on a WinXp system with VS.Net 2003. I'm trying to use it in a static CRT project. I get the following error whenever I compile: > error C1189: #error : "Mixing a dll boost library with a static runtime is a really bad idea..." I noticed that this is happening because BOOST_DYN_LINK is #defined in config.hpp. Apparently dynamic linking is the default for Boost? Windows does not support registration of clean-up functions for thread-specific storage (TSS, or TLS), but it does notify DLLs when a thread exits and this gives DLLs a chance to clean-up their thread-specific storage. So in order to make TSS work correctly, Boost.Threads is designed to be built only as a DLL on Windows. This means, as the error message says, that you need to use the DLL version of the CRT. Ben.

1 0

statically linking to Boost.Threads with msvc7
by Simmons, Aaron 03 Sep '04

03 Sep '04

I've built and installed boost on a WinXp system with VS.Net 2003. I'm trying to use it in a static CRT project. I get the following error whenever I compile: > error C1189: #error : "Mixing a dll boost library with > a static runtime is a really bad idea..." I noticed that this is happening because BOOST_DYN_LINK is #defined in config.hpp. Apparently dynamic linking is the default for Boost? Anyway, I've commented out this #define, but now I get a ton of warnings like the following > warning C4275: non dll-interface class 'std::logic_error' > used as base for dll-interface class 'boost::lock_error' and the project won't link > error LNK1104: cannot open file 'libboost_thread-vc71-mt-s-1_31.lib' I looked in Boost's lib folder and there aren't any static thread binaries (eg, "libboost_thread_xxx.lib). There are only the dynamic libraries (boost_thread_xxx.lib). Apparently something failed in the build process. I have to admit I didn't sit and watch the build process for the half-hour it took to build, so something may have gone wrong. Is there a build log somewhere? Is it possible to have bjam only build Boost.Threads so that I can see if there's an error without having to rebuild the entire library? Thanks, Aaron Simmons

2 1

boost::signals with Qt
by Alain Cormier 03 Sep '04

03 Sep '04

Hi, Just want to know *exactly* how to use boost::signals in a Qt project. I read this : http://www.boost.org/doc/html/ch06s04.html but I don't understand how to do it. I try to recompile boost with : "-sBUILD=<define>BOOST_SIGNALS_NAMESPACE=signalslib". After that, I try to directly change BOOST_SIGNALS_NAMESPACE in signals_common.hpp but didn't work neither. I use gcc 3.3.2 under Linux Mandrake 10 Thank you for any suggestion Al

3 3

RE: [Boost-users] statically linking to Boost.Threads with msvc7
by Ben Hutchings 03 Sep '04

03 Sep '04

Aaron Simmons <a-simmons1(a)ti.com> wrote: I've built and installed boost on a WinXp system with VS.Net 2003. I'm trying to use it in a static CRT project. I get the following error whenever I compile: > error C1189: #error : "Mixing a dll boost library with a static runtime is a really bad idea..." I noticed that this is happening because BOOST_DYN_LINK is #defined in config.hpp. Apparently dynamic linking is the default for Boost? Windows does not support registration of clean-up functions for thread-specific storage (TSS, or TLS), but it does notify DLLs when a thread exits and this gives DLLs a chance to clean-up their thread-specific storage. So in order to make TSS work correctly, Boost.Threads is designed to be built only as a DLL on Windows. This means, as the error message says, that you need to use the DLL version of the CRT. Ben.

1 0

nullary functor returning predefined value
by Yuri Muhitov 03 Sep '04

03 Sep '04

Hello All ! Please tell, can I create nullary functor returning predefined value, using boost::function & boost::bind ? Example uses "portable" syntax of boost::function : #include <boost/bind.hpp> #include <boost/function.hpp> struct InterfaceA; InterfaceA *getInterface (); template<typename T> T forward ( T t ) { return t; } int main ( int, char ** ) { typedef boost::function0<InterfaceA *,void> functor_type; // Value of InterfaceA * supplied by getInterface () function. Usage is straightforward : functor_type f1 = boost::bind ( getInterface ); InterfaceA *p = NULL; // Value of InterfaceA * is known here. How to create functor, returning it ? // functor_type f2 = boost::bind ( ??? ); // Possible workaround. Can I do this without forward<> template function ? functor_type f3 = boost::bind ( &forward<InterfaceA *>, p ); return 0; } Thanks! Yuri.

1 0