- Boost-users - lists.boost.org

shared_ptrs with std::mem_fn
by Steve Folly 07 May '04

07 May '04

Hi, I've converted a container to use shared_ptrs instead of regular pointers, now my for_each algorithm doesn't work: Before: class Attr; std::vector< Attr* > mAttributes; . . . std::for_each( mAttributes.begin(), mAttributes.end(), std::bind2nd( std::mem_fn( &Attr::Write ), output ) ); After: std::vector< shared_ptr<Attr> > mAttributes; Now it doesn't compile because (of course) Attr::Write is not a method of shared_ptr<Attr>. Do I have to use boost's bind and mem_fn objects instead of std? Thanks for any help. -- Regards, Steve.

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RE: [Boost-users] Re: shared_ptrs with std::mem_fn
by Mark Storer 07 May '04

07 May '04

> > Now it doesn't compile because (of course) Attr::Write is > not a method of > > shared_ptr<Attr>. > > > > Do I have to use boost's bind and mem_fn objects instead of std? > > Yes; bind and mem_fn handle this problem (and quite a few > others) automatically. Why is this a problem? I thought std::mem_fn called the function through the -> operator, which 'should' work (but obviously doesn't). I would think this would only crop up through mem_fun_ref, but then you wouldn't have a container of shared_ptr<Attr>, but Attr. --Baffled --Mark Storer Senior Software Engineer Verity, Inc.

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RE: [Boost-users] date_time clocks, microsec_clock, etc
by Darryl Green 07 May '04

07 May '04

> For those that need something portable we should be able to > get microsecond > resolution for Windows, Linux, and probably a few more... > > Jeff Microsecond resolution on linux? What interface provides this? I have a linux platform or 2 that I'm pretty sure won't provide it at present, but probably could with some kernel hacking, if only there was some sensible interface to connect it to user space. Darryl. ########################################################################## This e-mail is for the use of the intended recipient(s) only. If you have received this e-mail in error, please notify the sender immediately and then delete it. If you are not the intended recipient, you must not use, disclose or distribute this e-mail without the author's prior permission. We have taken precautions to minimise the risk of transmitting software viruses, but we advise you to carry out your own virus checks on any attachment to this message. We cannot accept liability for any loss or damage caused by software viruses. ##########################################################################

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how to install library in msvc
by kason aung 07 May '04

07 May '04

Dear all, I'm trying to install BGL on win 2k, vc++ 6 machine. I can't install BGL now. So if u have already successfully installed on msvc, i would like to know step-by-step installation procedure. I am looking forward to hearing good news from all of you. Thanks a lot for ur help and kindness. Regards, Kason _________________________________________________________________ Download games, logos, wallpapers and lots more at MSN Mobile! http://www.msn.com.sg/mobile/

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date_time clocks, microsec_clock, etc
by Aaron W. LaFramboise 07 May '04

07 May '04

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello, I'm a little curious whats in the works for date_time clock support. Specifically, there still doesn't seem to be anything better than a second-granularity clock for Win32. In addition, the UNIX clock is not always as precise as it could be. In particular, the popular Pentium and and some other architectures have some sorts of cycle-granularity hardware clock or similar that can exceed the usual operating system clock used for time. Really--and I have no idea what work is presently being done on this--it might do people in some problem domains (including myself, at times) a lot of good to have clocks with separate notions of precision and accuracy. For example, on a Pentium, operating systems I care about tend to have a maximum system clock accuracy around about a millisecond plus or minus some, and its probably difficult or tricky to get better than that. However, if the system clock was used in combination with the Pentium cycle counter, we could probably get precision in excess of a nanosecond. Perhaps an interface for such a clock system might be: typedef boost::date_time::clock<type_of_accuracy_you_need_here, type_of_precision_you_need_here> myclock; To get the above imagined clock, I might use: clock<microsecond_accuracy, cycle_precision> If the clock requested was unavailable on the platform, a compile time error might result. Of course, oftentimes we know the characteristics of a clock's accuracy or precision, such as the Pentium cycle counter, but we don't know exactly how precise it is, so it might be inappropriate to refer to that clock as nanosecond_precision when it really might not be. In summary, a reliable cross-platform sub second clock is one of the features I miss most in date_time, and one of the features I can afford to miss least. Is anyone working on remedying this right now? Aaron W. LaFramboise OpenPGP fingerprint: CFB4 D883 17ED E9BE 6F16 1BF7 969F E586 75AC 33C4 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFAlZuhxDYk2wAn5+8RAg5jAJ0XINhLFb4KikH+oK286PQfu6iMaQCgnTe5 SlmNLXTitPUWuUYMKrHIQgY= =bJvg -----END PGP SIGNATURE-----

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Using pool_alloc with std::map
by Kevin Lin 06 May '04

06 May '04

I am using boost::pool_alloc with std::map like this: typedef map<int, int, less<int>, pool_alloc<pair<int, int> > > MapT; MapT myMap; After myMap passes out of scope, I want to release unused memory from the pool. To do that, I need to get the type used to request chunks from the pool. pair<int, int> is not the answer since map uses rebind to get a different allocator. So how do I go about obtaining the correct singleton_pool interface? Your help is appreciated. -- Kevin Lin

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Question about compiling boost.1.31.0 on Solaris
by Wenning Qiu 06 May '04

06 May '04

I was trying to build the regex library from boost.1.31.0 on a Solaris 7 box using STLport.4.6.2. I have a couple of STLport versions installed in /opt. Here's how I built: o cd boost_1_31_0/libs/regex/build o /export/home/qiuw01/research/boost-jam-3.1.9/bin.solaris/bjam "-sTOOLS=sunpro-stlport" -sSTLPORT_PATH=/opt I was expecting STLport.4.6.2 to be used. However when I used ldd on the generated .so library, it shows a dependency on an old version of STLport in /usr/lib qiuw01$ ldd libboost_regex-sw-p-1_31.so librt.so.1 => /usr/lib/librt.so.1 libstlport_sunpro.so.4.5 => /usr/lib/libstlport_sunpro.so.4.5 libaio.so.1 => /usr/lib/libaio.so.1 libc.so.1 => /usr/lib/libc.so.1 libdl.so.1 => /usr/lib/libdl.so.1 /usr/platform/SUNW,Ultra-4/lib/libc_psr.so.1 <ethos:~/research/boost_1_31_0/bin/boost/libs/regex/build/libboost_regex.so/ sunpro-stlport/release> This doesn't seem to be right. Any comments? Thanks, Wenning Qiu

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boost::any and arithmetic ?
by Mailing List 06 May '04

06 May '04

Greetings all, as I'm new to this list, I'll keep my query short. It was suggested to me to use boost::any to store numeric values of whatever type (int, float, double, etc) so that I could use one std::list to store multiple values. I've looked through the header (any.hpp) and I admit it's a little hard for me to follow. I'm not what you'd call a superprogrammer... yet. :) I understand how to store a value in the boost::any object, but I'm not clear on how one would get that value back later (for display on screen, etc). What I'd really like to do is similar to one of the examples: --- snip --- struct property { property(); property(const std::string &, const boost::any &); std::string name; boost::any value; }; typedef std::list<property> properties; --- snip --- But I want to be able to do arithmetic with the resultant object(s): property T; property V; property Z; T [+-*/] Z; T = V [+-*/] Z T + [int,float,etc]; And so on. However, I want to make sure that the normal arithmetic type conversions (type promotions) take place (i.e. int + float returns a temporary object of type float). Example: boost::any value1; boost::any value2; boost::any value3; value1 = 127.915; value2 = 17; value3 = value1.getwhatevervalue() + value2.getwhatevervalue(); cout << value3.getwhatevervalue() << endl; value3 = value2.getwhatevervalue() + value1.getwhatevervalue(); cout << value3.getwhatevervalue() << endl; Both should return a temporary float with a value of 144.915. since I don't know how to get the value from boost::any, I just used getwhatevervalue() as an example. Sincerely, GRE

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Posix extended regexp
by Manish Madan 05 May '04

05 May '04

Hello, I'm new to boost and I had one question. I'm trying to match strings against regular expressions that are expected to be posix extended regular expressions. But for some reason, the modifier ^ doesn't seem to be working. For example, when I try to match "Manish" against "^[mM]anish.*", I am returned false. What am I doing wrong? Here's my short matching function: bool MatchRegExp(const std::string& matchThis, const std::string& againstThis) { try { const boost::regex e(againstThis);//, boost::regex_constants::icase); return boost::regex_match(matchThis, e, boost::regex_constants::extended); } catch(boost::bad_expression be) { return false; } } thanks Manish

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boost 1.30 / date_time / link problem with VC7
by Dan Dimerman 05 May '04

05 May '04

Hello, I'm having the following problem when linking a MSWindows MFC application with the static library libboost_date_time.lib using DevStudio .Net 7.0. The output looks like this: ------ Build started: Project: Main, Configuration: Debug Win32 ------ Linking... MSVCRTD.lib(ti_inst.obj) : error LNK2005: "private: __thiscall type_info::type_info(class type_info const &)" (??0type_info@@AAE@ABV0@@Z) already defined in libcmtd.lib(typinfo.obj) MSVCRTD.lib(ti_inst.obj) : error LNK2005: "private: class type_info & __thiscall type_info::operator=(class type_info const &)" (??4type_info@@AAEAAV0@ABV0@@Z) already defined in libcmtd.lib(typinfo.obj) LINK : warning LNK4098: defaultlib 'MSVCRTD' conflicts with use of other libs; use /NODEFAULTLIB:library Debug/Main.exe : fatal error LNK1169: one or more multiply defined symbols found I am working with the "Multi-threaded Debug (/MTd)" version of libraries. Tried using alternatives, but I got errors elsewhere and the errors above persisted. >From boost, I am using the library built at "My Documents\Visual Studio Projects\boost\libs\date_time\build\bin\libboost_date_time.lib\vc7\debug\run time-link-dynamic" Any help will be greatly appreciated... -- Dan Dimerman --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com) Version: 6.0.677 / Virus Database: 439 - Release Date: 04-May-04

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