January 2009 - Boost-users - lists.preview.boost.org

release vs. debug build
by Joseph A. Marks 02 Jan '09

02 Jan '09

After many debug builds, I am trying to build a "release" version -- sometimes known as a non-debug build or retail version. In any event, despite changing my .inc file to not use the following debug library, and doing a "build clear" (which is roughly equivalent to a rebuild all), I get the following: LINK : fatal error LNK1104: cannot open file 'libboost_date_time-vc90-mt-gd-1_37.lib' I tried to change the include libraries so that libboost_date_time-vc90-mt-1_37.lib was used instead. Am I required to rebuild the entire Boost system (e.g. using "jam" files) when I want to swtich from debug to release? Can anyone think of any obvious solution to this problem? Note: I obtain the Boost lists via digests, so it may take a while for me to interactively respond, if that becomes needed. Thanks Again, Sincerely, Joseph AMDG Joseph A. Marks PHONE: 612-788-9658 e-mail: josephamarks(a)yahoo.com

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Re: [Boost-users] shared_ptr and signals
by Max 02 Jan '09

02 Jan '09

Hello, Perhaps nobody is aware of (perpahs some are) that this simple use case has introduced another intersting and, probably, very useful scenario in which the Signals lib could be benificial. That is: Slot With Status. Have a look at this example: struct Slot { int sum; Slot() : sum(0) {} Slot(int i) : sum(i) {} int operator()(int i) { return sum += i; } }; void test_signals() { typedef boost::signal<int(int)> Signal; Signal sig; boost::shared_ptr<Slot> a( new Slot() ); boost::shared_ptr<Slot> b = a; sig.connect(boost::bind( &Slot::operator(), a, _1)); sig.connect(boost::bind( &Slot::operator(), b, _1)); sig.connect(boost::bind( &Slot::operator(), boost::shared_ptr<Slot>(a), _1)); std::cout << "\na.use_count() = " << a.use_count(); std::cout << "\nsum = " << sig(1) << std::endl; } The result is: a.use_count() = 5 sum = 3 the reason of use_count of the shared_ptr being 5 rather than 3 is the result of the copy semantics of the connect function. Hope this information is interesting. B/Rgds Max ----- Original Message ----- From: Frank Mori Hess <fmhess(a)speakeasy.net> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] shared_ptr and signals Date: 2009-1-1 01:30:05 On Tue Dec 30 12:47 , Steven Watanabe <watanabesj(a)gmail.com> sent: >James C. Sutherland wrote: >> Is it possible to use a shared_ptr object in a signal? >> >> I want something like >> >> struct A{ >> ... >> void operator()(){ ... } >> ... >> }; >> typedef boost::signal Signal; >> Signal mySignal; >> >> boost::shared_ptr a( new A() ); >> mySignal.connect(a); >Wrap the shared_ptr in a function object > >struct deref_call { > void operator()() const { > (*f)(); > } > boost::shared_ptr f; >}; bind can also be used to do this, since shared_ptr can be passed as the "this" argument when binding member functions: boost::shared_ptr a( new A() ); mySignal.connect(boost::bind(&A::operator(), a)); ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )

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AT Commands Sample Needed
by master master 02 Jan '09

02 Jan '09

I need a basic example for sending AT commands to mobile. This will require serial communication on COM port. If any one can send me any example of it. I want to do this using BOOST. By searching on GOOGLE I got this but this is not compiling. I know this code is wrong at several places. So can any give me a any right sample or modify it to be right. #include <iostream> #include <boost/asio.hpp> #include <boost/asio/serial_port.hpp> #include <boost/thread.hpp> #include <boost/system/error_code.hpp> #include <boost/system/system_error.hpp> #include <boost/bind.hpp> void handler(const boost::system::error_code& error) { std::cout << "read" << std::endl; } int main(int argc, char* argv[]) { using namespace std; using namespace boost; char read_msg_[512]; boost::asio::io_service io; asio::serial_port theport(io,"COM7"); theport.async_read_some(boost::asio::buffer(read_msg_),handler); io.run(); return 0; } Thank You Rahul To create something exceptional ________________________________ -Master4Master "Confidentiality Warning: This message and any attachments are intended only for the use of the intended recipient(s), are confidential, and may be privileged. If you are not the intended recipient, you are hereby notified that any review, re-transmission, conversion to hard copy, copying, circulation or other use of this message and any attachments is strictly prohibited. If you are not the intended recipient, please notify the sender immediately by return email, and delete this message and any attachments from your system.. Virus Warning: Although I have taken reasonable precautions to ensure no viruses are present in this email, I cannot accept responsibility for any loss or damage arising from the use of this email or attachment." Speak out for justice and peace, even if your voice trembles. ________________________________ Add more friends to your messenger and enjoy! Go to http://messenger.yahoo.com/invite/

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[boost-users][mpl, enable_if] checking if a type has specific dependant type
by Igor R 01 Jan '09

01 Jan '09

Hello, I'd like to define a trait that would evaluate to true for types that have some specific dependant type (DependentType), to use like this: template<class Type> func(int i, typename boost::enable_if<HasDependentType<Type> >::type* dummy = 0) { } I tried this way: template<class Type, class Enable = void> struct HasDependentType : mpl::false_ {}; template<class Type> struct HasDependentType<Type, typename Type::DependentType> : mpl::true_ {}; ...but it appears incorrect (partial specialization is never ised). Thanks in advance.

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[filesystem] windows program crashes in debug mode ( DbgUiConnectToDbg )
by Stephen 01 Jan '09

01 Jan '09

Trying to port a mac program onto windows. I've been having some trouble getting the boost portion of it to work. It appears to run fine in release mode*, but crashes when debugged. Below is an excised piece of code that seems to replicate the problem, and works perfectly in release mode but crashes when debugging. I'm using Code::Blocks under XP, with Boost 1.37 with Mingw 3.4.5 (linking to boost_system-mgw34-mt-1_37.lib and boost_filesystem-mgw34-mt-1_37.lib ) (Also: It doesn't crash when I run it in windows 95 compatibility mode, but that's not really an option because that completely breaks the program it's meant to be a part of). Code: #include "boost/filesystem/operations.hpp" #include "boost/filesystem/path.hpp" #include "boost/progress.hpp" #include <iostream> namespace fs = boost::filesystem; int main( int argc, char* argv[] ) { fs::path p("chapters"); fs::directory_iterator dir_iter(p), dir_end; std::cout<<"got here"; return 0; } Outputs "got here" in release, just crashes in debug, with backtrace: (gdb) backtrace #0 0x7c90120f in ntdll!DbgUiConnectToDbg () from C:\WINDOWS\system32\ntdll.dll #1 0x7c96c201 in ntdll!RtlpNtMakeTemporaryKey () from C:\WINDOWS\system32\ntdll.dll #2 0x0022f724 in ?? () #3 0x7c96c63e in ntdll!RtlpNtMakeTemporaryKey () from C:\WINDOWS\system32\ntdll.dll #4 0x00448270 in __gnu_cxx::__mt_alloc<wchar_t>::_S_binmap () #5 0x003e0000 in ?? () #6 0x00448278 in __gnu_cxx::__pool_alloc<wchar_t>::_S_force_new () #7 0x0022f798 in ?? () #8 0x7c96d826 in ntdll!RtlpNtMakeTemporaryKey () from C:\WINDOWS\system32\ntdll.dll #9 0x003e0000 in ?? () #10 0x00448270 in __gnu_cxx::__mt_alloc<wchar_t>::_S_binmap () #11 0x7c96d9dc in ntdll!RtlpNtMakeTemporaryKey () from C:\WINDOWS\system32\ntdll.dll #12 0x003e0000 in ?? () #13 0x00448278 in __gnu_cxx::__pool_alloc<wchar_t>::_S_force_new () #14 0x40000060 in ?? () #15 0x7c96d994 in ntdll!RtlpNtMakeTemporaryKey () from C:\WINDOWS\system32\ntdll.dll #16 0x003e0000 in ?? () #17 0x003e4418 in ?? () #18 0x40000060 in ?? () #19 0x003e0000 in ?? () #20 0x003e4418 in ?? () #21 0x00000000 in ?? () -------------------- Doing a similar build in Visual C++ 2008 with msvc builds of the library, I get the error Unhandled exception at 0x7c812aeb in filesystest.exe: Microsoft C++ exception: boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::filesystem::basic_filesystem_error<boost::filesystem::basic_path<std::basic_string<char,std::char_traits<char>,std::allocator<char> >,boost::filesystem::path_traits> > at memory location 0x0012fb34.. whether I run a debug build or not. -------------------- Compiling with the debug builds of the libraries (X-mgw34-mt-d-1_37.lib) didn't produce significantly-different looking other errors from the ones above. Someone on the internet ( http://forums.codeblocks.org/index.php/topic,8429.msg64317.html#msg64317 ) seemed to have a similar problem, but his solution isn't satisfactory for me (for the reason given below). Linking to single-threaded builds of boost didn't seem to make a difference either. Any help with this would be really appreciated. Stephen *I say 'appears to run fine' because, in the program that I'm trying to port, in windows all I see is a blank window (it's an SDL application); I can std<<cout directory structures from it though. This is most likely an unrelated problem, but I can't start to debug that until I've gotten this problem out of the way.

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proto for array expressions
by Daniel Oberhoff 01 Jan '09

01 Jan '09

Hi, I have skimmed over the new proto library a few times now. I am kind of excited about a clean implementation of ET. I have used blitz++ in a project before, but am disappointed, because it breaks unexpectedly in places, where it seems the et engine is just not smart enough, even though the expression makes a lot of sense. I ended up having to handcode a lot of things, avoiding which was the very reason I ever used blitz. So now I am back at hand coing in a new projects, using nothing but a few good iterators. Now with proto I was wondering how hard it would be to build an et engine for array math. Basically I am interested in general tensor notation, and the resulting expressions should be iteratable efficiently. think (advanced example): a_ij = b_i * (c_j - sum(d_ijk, k = [i-1,1]) so there should be math on the indices possible, and I should be able to iterate the expression to avoid direct index lookups wich are expensive with arrays, where indices must be multiplied by strides to get the memory address. other goodies would be optional range checks and the ability to pass subexpressions to template functions. also interesting might be transformations to automatically optimize expressions. a nice start would be maybe something simpler like just a_ij = b_i * (c_j - sum(d_ijk, k) where k is summed fully (over the whole range in d_ijk). can anymone give me an estimate on how hard this would be and where to start? Best Daniel Oberhoff Fraunhofer FIT St. Augustin Birlinghoven

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