August 2004 - Boost-users - lists.stage.boost.cppalliance.org

boost::shared_ptr and stl algorithms
by Bill Eidson 15 Apr '05

15 Apr '05

std::vector< boost::shared_ptr<T> > TVec; I want to write a function object to run std::for_each. to do somework against members of T and accumulate results in functor. My attempts have failed in VC7 with memory errors in my operator() method. struct fo { bool operator()( boost::shared_ptr<T>& t ) { return true; } }; Thanks in advance bille

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Will libraries built on WinNT run on Win98? (MinGW)
by Reed Hedges 31 Mar '05

31 Mar '05

I know that Win98 is not really supported, but is there any chance that libraries (specifically thread and regex) that were build on WinNT using MinGW work on Win98 (in MinGW)? My guess is no, but has anyone tried it? thanks reed

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Bug in lexical_cast<> with doubles
by Leon Raj 29 Jan '05

29 Jan '05

I think I've found a bug in the boost::lexical_cast<> library (v1.31.0) on WinXP SP1, MSVC 6.0 (sp5) and MSVC.NET 2003. --- Start code snippet --- #include <boost/lexical_cast.hpp> #include <iostream> int main( int argc, char* argv[] ) { double dMax = = std::numeric_limits< double >::max(); // On a Win32 x86 system, dMax is now 1.7976931348623157e+308 // This is successful and strMax is "1.797693134862316e+308" std::string strMax = boost::lexical_cast< std::string >( dMax ); try { double newDMax = boost::lexical_cast< double >( strMax ); std::cout << "Successfuly" << std::endl; } catch ( boost::bad_lexical_cast& ) { std::cout << "Failed to cast" << std::endl; } // On a Win32 x86 system, this always fails, // because (I think) strMax overflows a double, // because 1.7976931348623157e+308 is *rounded UP* // to 1.797693134862316e+308, which cannot be // represented by a double } --- End code snippet --- ----------------------------------------------------- Leon Raj Senior Engineer Invetech Pty. Ltd. Phone: +61 3 9211 7000 (Switchboard) +61 3 9211 7938 (DDI) leon.raj(a)invetech.com.au IMPORTANT - This e-mail and any attachments may be confidential. Any retransmissions, dissemination or other use of these materials by persons or entities other than the intended recipient is prohibited. If received in error, please contact us and delete all copies. Before opening or using attachments, check them for viruses and defects. Our liability is limited to resupplying any affected attachments. [Any representations or opinions expressed in this e-mail are those of the individual sender, and not necessarily those of Vision Systems Limited].

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global stream manipulators for the format library
by Justin Findlay 05 Sep '04

05 Sep '04

I've got some code that uses the format library to format output, not out of necessity, but rather out of a wanton enjoyment derived from using the syntax, having lately (relatively) discovered boost, prefering the boost::format simple syntax to the posix printf and std::ostringstream flavored solutions. The "problem" I have is that for the output of every double, I have to specify the precision: int main() { cout << setprecision(18); cout << format("Bunner p' air: %1% torr\t\tN$_2$: %2% torr\n" " C air: %3%\t\tN$_2$: %4%") % group(setprecision(18), bunner::air::pp_av) % group(setprecision(18), bunner::N2::pp_av) % group(setprecision(18), bunner::air::c_av) % group(setprecision(18), bunner::N2::c_av) << endl; //... return 0; } Is there a graceful solution, or am I using this library beyond what it was intended for? Something like the following naturally suggests itself, but I don't think it is standard compliant: the constructor doesn't seem to like using a static object, actually the linker couldn't find the 'prmanip' object. class Fmt { public: Fmt() { cout << "duh" << endl << prmanip << constants::pi << endl; } static std::_Setprecision setpr(const int&pr) { prmanip = std::setprecision(pr); return std::setprecision(pr); } static std::_Setprecision prmanip; }; int main() { cout << setprecision(18); Fmt::setpr(18); //... Justin

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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

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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

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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

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ublas aix test failures
by Daniel Elliott 02 Sep '04

02 Sep '04

Hello, I am interested in using ublas for a large government project. I noticed ublas (as of 8-19-2004) failed test3 on the visual age c++ compiler. What does this test exercise? We have currently installed the 1.31 libraries. Is this the same code that produced the test results? Thank you for your time. Sincerely, Dan Elliott --------------------------------- Do you Yahoo!? Win 1 of 4,000 free domain names from Yahoo! Enter now.

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Guidelines for effective exception usage
by Stephen torri 01 Sep '04

01 Sep '04

Are there any guidelines on where and when to use exceptions? Are there any boost components that deal with exceptions? Stephen -- Email: storri(a)torri.org

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internal properties and subgraphs.
by Jeffrey Holle 31 Aug '04

31 Aug '04

I've been experimenting with subgraphs. At present, they look quite useful in what I'm trying to do, but I've questions. If I add custom vertex and edge properties to my base graph, can I access these through a subgraph, using local vertex/edge descriptors? If not, is there a way of obtaining the mapping between global and local vertex/edge descriptors?

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