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RE: [Boost-users] boost::shared_ptr performance
by Tom Matelich 21 Nov '03

21 Nov '03

> -----Original Message----- > From: Matthew Wilson [mailto:stlsoft@hotmail.com] > Sent: Friday, November 14, 2003 4:23 PM > To: boost-users(a)lists.boost.org > Subject: [Boost-users] boost::shared_ptr performance > > > [I posted this in boost.devel, but got no response. > Presumably that was the > wrong group. :)] > I'm going to respond, but I don't have much to say. I would think that with all the work you put into making this comparison that you could probably determine why smart_ptr is slower than yours. To me this comparison is interesting but not without comparing your code with smart_ptr. Given the lack of code, I have to assume you're waiting for someone to say something like, "WOW!!! I gotta get me some of that!" boost::smart_ptr is already a well used class, so if you're looking to contribute, either post your code so we can maybe see how it is better, or see what it is that is missing from your code to make it faster. Benchmarks are useless without more information. Please make your code available so we can improve boost. If that is not your goal, come out and say so. Tom Matelich Boost Lover ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------

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RE: [Boost-users] lexical_cast causes level 4 warnings w/ VC7.1
by Sam Partington 20 Nov '03

20 Nov '03

Bruce Johnston <mailto:c_kernel@hotmail.com> wrote: > I'm working on a project with strict requirements for the > build settings, > including mandatory warning level 4 and "treat warnings as errors". I > discovered that lexical_cast causes warnings C4127, C4511, > and C4512 when > compiling with warning level 4 using VC7.1. Try the following > code for a > quick repro: 4511 and 4512 are useless warnings. They are telling you that the copy constructor and assignment operator are inaccessible. Even though you're not trying to call them. Take the following code class noncopyable { private: noncopyable(const noncopyable&); noncopyable& operator=(const noncopyable&); }; class a_resource : noncopyable { // ... }; // ... { a_resource res; } Clearly a_resource is not meant to be copied, the developer has gone to lengths to make that clear. Indeed it never is copied, or assigned, yet the warnings will still be issued. C4127 is also awkward. As it gives warnings for some common idioms. It refers to conditional expressions being constant. So : do { XXX } while(0); Gives the warning, which is a common implementation of an ASSERT() macro, and likewise // in an header : const bool debug = false; // in code : if (debug) { } does also. None of these technigues indicate a possible error in code. Ideally all three of these warnings would be disabled in config.hpp. > As an aside, what warning level is typically used by > developers working on > Boost? On VC6 we build on warning level 3, 4 is just too noisy with the built in headers. On VC7.1 we use level 4, but with C4127, C4511, C4512 switched off. HTH Sam ****************** This e-mail has been sent from Imagination Technologies Limited. PowerVR, Metagence, Ensigma and PURE Digital are divisions of Imagination Technologies Limited. The information contained in this e-mail, including any attachment, is confidential and may be legally privileged. It is intended solely for the addressee(s) and access to this e-mail by anyone else is unauthorised. If you are not the intended recipient, any disclosure, copying or distribution or use of the information contained in this e-mail, is prohibited and may be unlawful. If you have received this e-mail in error, please notify the sender by return e-mail and then delete it from your system. Internet communications cannot be guaranteed to be secure, error or virus-free. The sender does not accept liability for any errors or omissions which arise as a result. Any views expressed in this message are those of the author, except where the author specifies and, with authority, states them to be the views of Imagination Technologies Ltd.

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Re: [Boost-users] Re: filesystem::directory_iterator::operator++() never returns <--never mind
by Beman Dawes 20 Nov '03

20 Nov '03

At 07:02 PM 11/19/2003, John.Wismar(a)alldata.com wrote: > >OK, I found it. > >Upon yet another search of the archive, I found it: I was using the >single-threaded version of the library in a multi-threaded app. > >Sorry for the bandwidth! Actually, it is helpful. It gives us more incentive to work on reliability enhancements. Thanks, --Beman

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RE: [Boost-users] Re: boost::shared_ptr performance
by Tom Matelich 20 Nov '03

20 Nov '03

> -----Original Message----- > From: Matthew Wilson [mailto:stlsoft@hotmail.com] > Sent: Wednesday, November 19, 2003 11:27 AM > To: boost-users(a)lists.boost.org > Subject: [Boost-users] Re: boost::shared_ptr performance > > > > > > > > [I posted this in boost.devel, but got no response. > > > Presumably that was the > > > wrong group. :)] > > > > > > > I'm going to respond, but I don't have much to say. I > would think that > with all the work you put into making this comparison that you could > probably determine why smart_ptr is slower than yours. To me this > comparison is interesting but not without comparing your code with > smart_ptr. Given the lack of code, I have to assume you're > waiting for > someone to say something like, "WOW!!! I gotta get me some of that!" > > No, I was seeking information, as I said. > > "There are environment settings for which boost::shared_ptr will > perform much better. If that's so, can someone help me out > with suggestions > of what defines to make?" > > It turns out that there are. > > If I was wanting to make a splash, I'd got for a dip down at > the beach. :) Sorry for any appearance of hostility. I'll check out the devel thread. ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------

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lexical_cast causes level 4 warnings w/ VC7.1
by Bruce Johnston 20 Nov '03

20 Nov '03

I'm working on a project with strict requirements for the build settings, including mandatory warning level 4 and "treat warnings as errors". I discovered that lexical_cast causes warnings C4127, C4511, and C4512 when compiling with warning level 4 using VC7.1. Try the following code for a quick repro: #include <string> #include <iostream> #include "boost/lexical_cast.hpp" int main() { std::string helloFactor = boost::lexical_cast<std::string>( 7 ) ; std::cout << "Hello # " << helloFactor << std::endl ; return 0 ; } Builds fine at warning level 3, fails with /W4 and /WX. As an aside, what warning level is typically used by developers working on Boost? -Bruce Johnston Simba Technologies

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Re: filesystem::directory_iterator::operator++() never returns <--never mind
by John.Wismar＠alldata.com 20 Nov '03

20 Nov '03

OK, I found it. Upon yet another search of the archive, I found it: I was using the single-threaded version of the library in a multi-threaded app. Sorry for the bandwidth! --------------------- John Wismar john.wismar(a)alldata.com In a previous state of enlightnment, I wrote: I'm using the fielsystem library's directory_iterator class to collect information about the files in a directory. I'm using VC7.0, and Boost 1.30.2. My logic looks something like this: ---------------------------------------------------------------------- class DirInfo { public: DirInfo(fs::path aPath) : myPath(aPath){} void scan(); void addFile(fs::path); private: fs::path myPath; } void DirInfo::scan () { fs::directory_iterator itEnd; for (fs::directory_iterator it(myPath); it != itEnd; ++it) { TRACE("File: %s\n", it->string().c_str()); if (!fs::is_directory(*it)) { addFile(*it); } } } DirInfo di(fs::path("C:\\temp\\", fs::native); di.scan(); ---------------------------------------------------------- This successfully goes through all of the files (and subdirectories) in the given directory, but after the last item, the next call to fs::directory_iterator::operator ++() never returns. If anyone has any suggestions or ideas, I would love to hear them!! Thanks! The call stack at the point where execution seems to lock up looks like this: ntdll.dll!NtDelayExecution() + 0xc kernel32.dll!_Sleep@4() + 0xb MyApp.exe.exe!boost::detail::lightweight_mutex::scoped_lock::scoped_lock(boost::detail::lightweight_mutex & m={...}) Line 96 + 0xa C++ MyApp.exe.exe!boost::detail::sp_counted_base::release() Line 132 + 0xf C++ MyApp.exe.exe!boost::detail::shared_count::~shared_count() Line 380 C++ MyApp.exe.exe!boost::shared_ptr<boost::filesystem::directory_iterator::dir_itr_imp>:: ~shared_ptr<boost::filesystem::directory_iterator::dir_itr_imp>() + 0x2e C++ MyApp.exe.exe!boost::shared_ptr<boost::filesystem::directory_iterator::dir_itr_imp>::reset () Line 217 C++ MyApp.exe.exe!boost::filesystem::directory_iterator::m_inc() Line 256 C++ > MyApp.exe.exe!boost::filesystem::directory_iterator::operator++() Line 88 + 0x2b C++ MyApp.exe.exe!DirInfo::scan() Line 63 + 0x1a C++ --------------------- John Wismar john.wismar(a)alldata.com

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filesystem::directory_iterator::operator++() never returns
by John.Wismar＠alldata.com 19 Nov '03

19 Nov '03

I'm using the fielsystem library's directory_iterator class to collect information about the files in a directory. I'm using VC7.0, and Boost 1.30.2. My logic looks something like this: ---------------------------------------------------------------------- class DirInfo { public: DirInfo(fs::path aPath) : myPath(aPath){} void scan(); void addFile(fs::path); private: fs::path myPath; } void DirInfo::scan () { fs::directory_iterator itEnd; for (fs::directory_iterator it(myPath); it != itEnd; ++it) { TRACE("File: %s\n", it->string().c_str()); if (!fs::is_directory(*it)) { addFile(*it); } } } DirInfo di(fs::path("C:\\temp\\", fs::native); di.scan(); ---------------------------------------------------------- This successfully goes through all of the files (and subdirectories) in the given directory, but after the last item, the next call to fs::directory_iterator::operator ++() never returns. If anyone has any suggestions or ideas, I would love to hear them!! Thanks! The call stack at the point where execution seems to lock up looks like this: ntdll.dll!NtDelayExecution() + 0xc kernel32.dll!_Sleep@4() + 0xb MyApp.exe.exe!boost::detail::lightweight_mutex::scoped_lock::scoped_lock(boost::detail::lightweight_mutex & m={...}) Line 96 + 0xa C++ MyApp.exe.exe!boost::detail::sp_counted_base::release() Line 132 + 0xf C++ MyApp.exe.exe!boost::detail::shared_count::~shared_count() Line 380 C++ MyApp.exe.exe!boost::shared_ptr<boost::filesystem::directory_iterator::dir_itr_imp>:: ~shared_ptr<boost::filesystem::directory_iterator::dir_itr_imp>() + 0x2e C++ MyApp.exe.exe!boost::shared_ptr<boost::filesystem::directory_iterator::dir_itr_imp>::reset () Line 217 C++ MyApp.exe.exe!boost::filesystem::directory_iterator::m_inc() Line 256 C++ > MyApp.exe.exe!boost::filesystem::directory_iterator::operator++() Line 88 + 0x2b C++ MyApp.exe.exe!DirInfo::scan() Line 63 + 0x1a C++ --------------------- John Wismar john.wismar(a)alldata.com

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regex static lib for x86 emulator
by Reuti＠sdc.canon.co.in 19 Nov '03

19 Nov '03

I can build static library for ARM processor. But when building for X86 emulator I am getting following error. LINK : fatal error LNK1104: cannot open file 'boost_regex_vc6_sss.lib' Please help. Thanks in advance. Reuti

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gregorian: explicit date::date(date_int_type) ?
by Michael Haubenwallner 19 Nov '03

19 Nov '03

Hi, I'm preparing my company's step from C to C++, and when i use boost::date_time::*, there's a great danger to make mistakes like this with boost-1.30.2: #include <time.h> #include <iostream> #include <boost/date_time/posix_time/posix_time.hpp> using namespace boost::posix_time; using namespace boost::gregorian; int main() { time_t now = time(0); try { ptime time(now); // mistake cerr << to_simple_string(time) << endl; } catch (exception const& e) { cerr << "error: " << e.what() << endl; } } The problem is that the time_t in this case is treated as a day-count from which a gregorian::date() is implicitly constructed. When digging through the gregorian::date, i see that the constructors of date_time::date() from date_int_type and date_rep_type protected. So, wouldn't it be better to make the gregorian::date() constructors from date_int_type and date_rep_type explicit, to get a compile-time error with this sample rather than the out-of-range-exception "Year is out of valid range: 1400..10000" ? And another reason to make this constructor explicit might be that date_rep_type is the internal representation of date(), so when constructing date() with a day_count, you have to know the epoch, and then constructing date() should be done explicitly... What do you think about this ? Thanks, Michael Haubenwallner -- Michael Haubenwallner SALOMON Automation GmbH Forschung & Entwicklung A-8114 Friesach bei Graz T +43 3127 200 308 F +43 3127 200 22 mailto:michael.haubenwallner@salomon.at http://www.salomon.at

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Invert Matrix
by JEFFREY CULLINA 18 Nov '03

18 Nov '03

I have devoleped code to derive a simple matrix expression: [K]*[D]=[R] wher D is an unknown vector. I am looking for code to do two things: 1. Invert [K] to get the expression [D]=inv([K])*[R] 2. Solve the equation in 1 It looks like the UBLAS toolkit provides a function _t_sv to solve the equation, but I do not see anything to help me invert the matrix. Is there code available to help me invert a matrix? While I am at it, I may as well ask if _t_sv is the best function to use to solve the system. Thanks, Jeff

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