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boost::any: explicit constructor?
by Vladimir Prus 25 Feb '04

25 Feb '04

Hi, I just had a couple of bugs caused by the fact that constructor of boost::any is not explicit. For example: void do_something(boost::any& v) { ... } class variable { ///// boost::any& value() {} }; variable v; do_something(v); The intention was to call do_somethin on 'v.value()' but non-explicit ctor is happy to accept 'variable', after which 'do_something' breaks. Anybody has an opinion? Is non-explicit ctor really necessary? - Volodya

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[config] fix for BCB and BOOST_NO_MEMBER_TEMPLATE_FRIENDS
by Pavel Vozenilek 25 Feb '04

25 Feb '04

I believe config macro BOOST_NO_MEMBER_TEMPLATE_FRIENDS should be defined for BCB 6. Currently it is defined only for BCB 5.5.1 and less but with BCB 6: - compiling test file boost_no_mem_templ_frnds.cxx fails, - the problem shows in Serialization library too. So I recommend to change borland.hpp to define this macro for BCB 6 (and likely for Kylix which is simply BCB6 ported to Linux). BCB6 patch 4 == 0x564 Kylix = 0x570 /Pavel

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Re: [utility] question on prior(x,n)
by Bjorn.Karlsson＠readsoft.com 25 Feb '04

25 Feb '04

> From: Daniel Frey [mailto:daniel.frey@aixigo.de] > > > > Well, you came up with the 2-arg version. > > That was Daniel Wallin (too many Daniels error?). I guess this also > explains why I had the feeling we were talking past each > other a bit :) Heh, according to the docs it was Daniel Walker. This name-calling is getting interesting. ;-) Bjorn

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Re: [utility] question on prior(x,n)
by Bjorn.Karlsson＠readsoft.com 25 Feb '04

25 Feb '04

> From: David Abrahams [mailto:dave@boost-consulting.com] > > See counting_iterator for inspiration as to why this might be useful. Got it, thanks. Perhaps these type requirements should be spelled out in the docs (proposed patch below)? And maybe is_full_iterator_traits in detail/iterators.hpp could be slightly changed and turned into a first-class traits "is_iterator", which would then be used for dispatching next/prior calls to std::advance when applicable? Although this would work, I'm not sure that the added dependencies and complexity are worth it - if possible, I think that dropping the two-argument versions of next and prior would be best. Bjorn [Note: The most interesting change to the doc are the following four lines. The one-argument version of next() and prior() can be used with any type that provides operator++() and operator--(), respectively. The two-argument version of next() and prior() can be used with any type that provides operator+() and operator-(), with the exception of iterator types, which only require operator++() and operator--() for both versions. ] *** utility.htm.orig Wed Feb 25 11:47:07 2004 --- utility.htm Wed Feb 25 11:48:17 2004 *************** *** 41,61 **** T next(T x) { return ++x; } template <class T, class Distance> ! T next(T x, Distance n) ! { ! std::advance(x, n); ! return x; ! } template <class T> T prior(T x) { return --x; } template <class T, class Distance> ! T prior(T x, Distance n) ! { ! std::advance(x, -n); ! return x; ! }</pre> </blockquote> Usage is simple: <blockquote> --- 41,54 ---- T next(T x) { return ++x; } template <class T, class Distance> ! T next(T x, Distance n); template <class T> T prior(T x) { return --x; } template <class T, class Distance> ! T prior(T x, Distance n); ! </pre> </blockquote> Usage is simple: <blockquote> *************** *** 66,71 **** --- 59,68 ---- The distance from the given iterator should be supplied as an absolute value. For example, the iterator four iterators prior to the given iterator <code>p</code> may be obtained by <code>prior(p, 4)</code>. + The one-argument version of next() and prior() can be used with any type that provides + operator++() and operator--(), respectively. The two-argument version of next() and prior() + can be used with any type that provides operator+() and operator-(), with the exception of + iterator types, which only require operator++() and operator--() for both versions. Contributed by <a href="../../people/dave_abrahams.htm">Dave Abrahams</a>. Two-argument versions by Daniel Walker. <h2><a name="Class_noncopyable">Class noncopyable</a></h2> Class noncopyable is a base class.  Derive your own class

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XSL regression reporting changes
by Misha Bergal 25 Feb '04

25 Feb '04

I have checked in the modifications to split the failed test logs HTML file (links.html) into on HTML file per test log. The regression testers using xsl_reports will need to update their upload scripts. -- Misha Bergal MetaCommunications Engineering

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warning when using borland toolset
by Gennadiy Rozental 25 Feb '04

25 Feb '04

I am getting following warning when I try to compile using Borland toolset: ...boost\tools/build\v1\borland-tools.jam:182: in include-tools warning: unknown rule W32_GETREG ...boost\tools/build\v1\boost-base.jam:760: in relevant-features ...boost\tools/build\v1\boost-base.jam:828: in select-properties ...boost\tools/build\v1\boost-base.jam:799: in variant ...boost\tools/build\v1\features.jam:179: in boost-build ...boost\boost-build.jam:16: in module scope ...boost\tools/build\v1\borland-tools.jam:182: in include-tools (actually repeated multiple times) any suggestions? Gennadiy

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The art of naming namespaces [was: Re: algorithms namespace]
by Bjorn.Karlsson＠readsoft.com 25 Feb '04

25 Feb '04

> From: Peter Dimov [mailto:pdimov@mmltd.net] > > > You can always shorten it in your code with an alias. > > This is precisely what makes it dangerous. Design mistakes that have a > trivial workaround are the worst, because you will never get > the feedback > that will set you on the right path. Everyone just patches around it > locally. I agree. If a name "works", programmers will use it. If it's too long, it'll be aliased or removed with using declarations/directives. If it's too cryptic, it'll be aliased or removed with using declarations/directives. I think that two equally valid points have been made in this thread: 0) If the name is too long, people won't use it as-is. This diminishes the information that the name carries. 1) If the name is too short/cryptic, people won't even know what it's supposed to mean. If one agrees to the above, it seems reasonable to search for a short name with lots of expressive power (oh yeah, why didn't I think of _that_...). I'd say that for boost::filesystem, Dave's suggestion "files" would be a great compromise. I'd say that for algorithms, a special name isn't actually needed; it doesn't add any information, because anyone who calls sort, trim, hash, or whatever, understands that somewhere an algorithm is involved. boost::, std::, you_name_it::, will get the job done. [Note: Some libraries (Spirit and MPL come to mind) are sexy enough to handle a non-related word/acronym as their name, without sacrificing informational value. Now that's good branding!] > No we do not. The abbrv anlgy is flwd. It's more like English::this > English::kind English::of English::writing versus en::this > en::alternative > en::style. What's "en"? ;-) > > Also a global search is easier if the letters to be searched for are > > more or less a unique set. > > Of course it isn't. Your global search for 'filesystem' will > only find using > directives and namespace alias directives. A global search > for 'fs' will > stand a better chance to point you to the lines that actually > use something > from 'fs'. Good point. Bjorn "Put the bicycle shed next to my office" Karlsson

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Re: Proposed modifications to make compose_f_*_t use *ary_traitsand call_traits
by Jonathan Turkanis 25 Feb '04

25 Feb '04

". Sneechy" <sneechy(a)hotmail.com> wrote in message news:F295smOU9Xlk0H1jLUL00026d99@hotmail.com... > Traits classes can make templates more generic and otherwise flexible > (performance-wise for example). I believe that the compose_f_*_t template > class family in boost/compose could benefit from using *ary_traits (from > boost/functional), and boost/call_traits. Are you aware that compose has been deprecated? Jonathan

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Lambda patch to enable *_1 for smart pointers
by Peter Dimov 25 Feb '04

25 Feb '04

I've taken the liberty to apply the following patch to boost/lambda/detail/operator_return_type_traits.hpp: *** 19,24 **** --- 19,26 ---- #include "boost/lambda/detail/is_instance_of.hpp" #include "boost/type_traits/same_traits.hpp" + #include "boost/indirect_reference.hpp" + #include <cstddef> // needed for the ptrdiff_t #include <iosfwd> // for istream and ostream *************** *** 221,227 **** // A is a nonreference type template <class A> struct contentsof_type { ! typedef typename std::iterator_traits<A>::reference type; }; // this is since the nullary () in lambda_functor is always instantiated --- 223,229 ---- // A is a nonreference type template <class A> struct contentsof_type { ! typedef typename boost::indirect_reference<A>::type type; }; // this is since the nullary () in lambda_functor is always instantiated This (hopefully) makes *_1 work for smart pointers. Feel free to revert the patch if it breaks something; I don't have a full regression test system set up. -- Peter Dimov http://www.pdimov.com

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Announce: Metrowerks Pro 9 Windows Now Shipping
by Howard Hinnant 25 Feb '04

25 Feb '04

If the kind moderators allow this through I promise not to send such blatantly commercial announcements to the boost developers list again (at least for awhile :-) ). <commercial> Here is contact info which can also be found at our website www.metrowerks.com: info(a)metrowerks.com US Mail: Metrowerks Sales Metrowerks 9801 Metric Blvd. Austin, TX 78758 Telephone: Toll Free: 800-377-5416 International: +1 512 997 4700 Fax: +1 512 997 4901 I'm personally very proud of many of the Pro 9 features which include pseudo move semantics for vector. For example you might want to try running the following demo under CodeWarrior and your 2nd favorite compiler (optimize for speed): #include <string> #include <set> #include <iostream> #include <time.h> #include <vector> int main() { std::string s(20, ' '); std::multiset<std::string> ms; for (int i = 0; i < 100; ++i) ms.insert(s); std::vector<std::multiset<std::string> > v(10000, ms); clock_t t = clock(); v.erase(v.begin()); t = clock() - t; std::cout << (double)t/CLOCKS_PER_SEC << '\n'; } Assuming your clock() function has sufficient resolution to produce reasonable results on your platform you might be interested in the results. Of course this should be old hat to Mac users (Pro 9/Mac has been out for months). Fwiw, here's what I'm getting on my Mac: [G4:~/Documents/Development/JunkMac] hinnant% ./helloworld 0.01 // CodeWarrior Pro 9 [G4:~/Documents/Development/JunkMac] hinnant% g++ -v Reading specs from /usr/libexec/gcc/darwin/ppc/3.3/specs Thread model: posix gcc version 3.3 20030304 (Apple Computer, Inc. build 1495) [G4:~/Documents/Development/JunkMac] hinnant% g++ -O4 HelloWorld.cp [G4:~/Documents/Development/JunkMac] hinnant% ./a.out 1.08 </commercial> -Howard

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