February 2012 - Boost - lists.preview.boost.org

[filesystem] operations.hpp Won't Compile with VC10 using Boost 1.47
by Stewart, Robert 14 Feb '12

14 Feb '12

When I try to include boost/filesystem/operations.hpp, my code won't compile on MSVC 10 (Visual Studio 2010). The error is from boost/filesystem/v3/config.hpp:49: # if defined( BOOST_NO_STD_WSTRING ) # error Configuration not supported: Boost.Filesystem V3 and later requires std::wstring support # endif I found only the following places where BOOST_NO_STD_WSTRING is defined, and none should apply, so I'm at a loss to understand why my build fails. What have I missed? ./config/platform/amigaos.hpp:12:#define BOOST_NO_STD_WSTRING ./config/platform/symbian.hpp:85:# define BOOST_NO_STD_WSTRING ./config/stdlib/libstdcpp3.hpp:23:# define BOOST_NO_STD_WSTRING ./config/stdlib/modena.hpp:22:#define BOOST_NO_STD_WSTRING ./config/stdlib/sgi.hpp:100:# define BOOST_NO_STD_WSTRING ./config/stdlib/stlport.hpp:109:# define BOOST_NO_STD_WSTRING _____ Rob Stewart robert.stewart(a)sig.com Software Engineer using std::disclaimer; Dev Tools & Components Susquehanna International Group, LLP http://www.sig.com ________________________________ IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses.

2 1

[config] Flags for default/delete special member functions?
by Daryle Walker 14 Feb '12

14 Feb '12

Can we add macro constants to boost/config.hpp that indicate if marking (special) member functions as "= default" or "= delete" is supported? Daryle W.

2 1

[trunk] compilation errors on MSVC 8
by lcaminiti 14 Feb '12

14 Feb '12

Hello all, I get the errors below if I run bootstrap from the latest trunk checkout using MSVC 8 on Windows 7... (the trunk seems instead to work with GCC 4.5.3 on Cygwin). Thanks. --Lorenzo Setting environment for using Microsoft Visual Studio 2005 x86 tools. ### ### Using 'vc8' toolset. ### C:\Users\lorcam\Desktop\code\boost-trunk\tools\build\v2\engine>if exist bootstrap rd /S /Q bootstrap C:\Users\lorcam\Desktop\code\boost-trunk\tools\build\v2\engine>md bootstrap C:\Users\lorcam\Desktop\code\boost-trunk\tools\build\v2\engine>cl /nologo /RTC1 /Zi /MTd /Fobootstrap/ /Fdbootstrap/ -DNT -DYYDEBUG -wd4996 kernel32.lib advapi32.lib user32.lib /Febootstrap\jam0 command.c compile.c constants.c debug.c execnt.c filent.c function.c glob.c hash.c hdrmacro.c headers.c jam.c jambase.c jamgram.c lists.c make.c make1.c object.c option.c output.c parse.c pathunix.c regexp.c rules.c scan.c search.c subst.c timestamp.c variable.c modules.c strings.c filesys.c builtins.c md5.c pwd.c class.c w32_getreg.c native.c modules/set.c modules/path.c modules/regex.c modules/property-set.c modules/sequence.c modules/order.c command.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' compile.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' constants.c debug.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' execnt.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' filent.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' function.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' glob.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' hash.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' hdrmacro.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' headers.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' jam.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' jambase.c jamgram.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' lists.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' make.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' make1.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' object.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' option.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' output.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' Generating Code... Compiling... parse.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' pathunix.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' regexp.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' rules.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' scan.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' search.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' subst.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' timestamp.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' variable.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' modules.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' strings.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' filesys.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' builtins.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' md5.c pwd.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' class.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' w32_getreg.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' native.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' set.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' path.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' Generating Code... Compiling... regex.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' property-set.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' sequence.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' order.c c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2016: C requires that a struct or union has at least one member c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(466) : error C2061: syntax error : identifier 'pid_t' c:\users\lorcam\desktop\code\boost-trunk\tools\build\v2\engine\jam.h(468) : error C2059: syntax error : '}' Generating Code... -- View this message in context: http://boost.2283326.n4.nabble.com/boost-trunk-compilation-errors-on-MSVC-8… Sent from the Boost - Dev mailing list archive at Nabble.com.

3 3

Re: [boost] [optional] generates unnessesary code for trivial types
by Andrzej Krzemienski 14 Feb '12

14 Feb '12

> > But even that appears like a non-obvious thing to me. Would other people > > here in the list, and also developers in general agree that it is ok that > > you have output operation but no input operation? I think that in the > > standard library they always go in pairs. (I am not sure, though). > > In my own code I often find myself defining only output operators. For things > more complex than enums or numerics I usually handle input with specialized > solutions, with tools line Boost.Spirit. As for the standard library, I'm not > sure but dos thread::id have an input operator? > > Also, how would you implement it? what should an uninitialized optional > > print? Nothing? but how is having printed an uninitialized optional<int> > > different that not having printed anything? A question mark? but how would > > the following two be different: > > FWIW, boost::optional provides both input and output. > > If you propose to provide only output operation, then it looks like you > > want this for some sort of logging. But perhaps it is better to have some > > overloaded function toString() that converts all the types to strings. > > Usually the string format that works for one program does not work for the > > other. And there appears to be no natural/intuitive way of representing any > > type (like optional) as text. > > I usually dislike toString and alike methods. I think, manipulators are more > flexible and modularized approach. Do you think it would be possible to > provide different manipulators to fulfill different IO requirements? I have checked the standard and indeed thread::id provides operator<< without the matching operator>>, so this asymmetry would not be a precedent in the standard. Although the situation with thread::id is speciffic. ID's are assigned by the OS and trying to assign them by other means would definitely be an error. I also checked boost::optional and it provides both (I learned two new things today). Uninitialized optional of any type renders "--" (two dashes); whereas initialize optional always prepends a space. I am not sure if this does not look like hack; but people already said this would not be much of a problem. Certainly, there ways to make the output of optional configurable. I am not sure manipulators would be my preference. An alternative would be the approach that Boost.Date_time has adopted: you set your preference per stream (plus one global setting) by means of locale mechanism. However, when it comes to proposing stuff in front of the ISO committee, there is one other factor, which I failed to mention yet. It is the "fragility" of the process. I am concerned that if anything turns out to be controversial, the whole Optional would be at risk of being rejected. This might be an exaggeration (I have never gone through the process of proposing something and then pushing it through), but Optional has already been proposed by Fernando (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1878.htm) and rejected; primarily for two things: operators -> and * and the semantics for optional reference assignment (see http://lists.boost.org/Archives/boost/2005/10/95079.php) I would much like to avoid the situation where Optional (which I believe is very useful to wide variety of programmers) would be rejected because of one additional, however tiny, controversy of streaming operator. Regards, &rzej

3 2

Re: [boost] [optional] generates unnessesary code for trivial types
by Hite, Christopher 14 Feb '12

14 Feb '12

From: Domagoj Saric <domagoj.saric(a)littleendian.com> > > Maybe I'm missing something, but I don't see the justification. > IMO it seems that, yes, you are making the same mistake as Lucanus, thinking > about "The Universe" only as/through your POV of your personal problem domain: > a) (optional models optionally holding an object) + (objects can be held by > value and by reference) = optional<T&> perfectly logical I'm really not. Give me a use case. Do they make sense being passed as parameters/returns? Do they make sense being stored? I just see some corner case of optional being turned into a replacement for regular pointer. Why not just make dumb_ptr<T>? If you want you can make it streamable and give it clean construction. What is it you really want from optional<T&>? Does anyone use it a lot? Is it like std::vector<bool>? > b) creating special cases (e.g. for T&) creates special problems in generic code My point exactly. I'd make it work for completeness but not bother to optimize. Chris

4 6

Discovering C++11 lambda argument and result types to construct boost::function
by Frank Birbacher 14 Feb '12

14 Feb '12

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi! On comp.lang.c++.moderated I talked to Daniel Krügler about how to discover argument and result types from C++11 lambdas in a template context. The thread has the title "How to discover argument and result types from lambda for constructing std::function?" https://groups.google.com/d/topic/comp.lang.c++.moderated/qaMECIUlJp0/discu… The task is to provide a function template "make_function" that takes a C++11 lambda expression and returns a boost::function with the correct signature to call the lambda. This may be extended to accept any other callable type. Is there such a thing already in Boost? I'd like to add it. Would it go to Boost.Function alone? Or would parts fit into TypeTraits? Does Doug still maintain Boost.Function? Frank -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: keyserver x-hkp://pool.sks-keyservers.net iEYEARECAAYFAk80RsMACgkQhAOUmAZhnmr5gACdGI6q9Xi1SbtpHs23GlAhU9uu Y3kAnjCpiZFGJp+IpnFVS3gmtZOqZp42 =GGdI -----END PGP SIGNATURE-----

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Re: [boost] [optional] generates unnessesary code for trivial types
by Andrzej Krzemienski 13 Feb '12

13 Feb '12

> I use optional references in my code, in cases like the following: > I have an operation, which processes some elements, and some of the > elements constitute special cases. The caller of the operation may or may > not want to know about the special cases that arose, so they can optionally > pass in a container which will be populated with the special cases: > void some_operation(inputs, optional<vector<case>&> special_cases = none) > { > for (...) > { > ... > if (special_case) > { > ... > if (special_cases) > special_cases->push_back(current_case); > } > } > } > Before I discovered optional, I used a plain reference, but that was annoying > because I had to create a dummy vector to be used as the default argument. > (The other alternative would have been to use a pointer, but then the caller > has to use the uglier syntax of passing in "&special_cases" rather than > "special_cases"). Nathan, going back to the same question I asked Andrey ( http://groups.google.com/group/boost-developers-archive/msg/704971a1eb63b3d2) it looks like your use case would still work if we disabled any sort of assignment for optional references (even the assignment from boost::none for resetting). Am I correct? Regards, &rzej

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Re: [boost] [optional] generates unnessesary code for trivial types
by Brian Wood 13 Feb '12

13 Feb '12

Andrzej Krzemienski: > But even that appears like a non-obvious thing to me. Would other people > here in the list, and also developers in general agree that it is ok that > you have output operation but no input operation? I think that in the > standard library they always go in pairs. (I am not sure, though). I haven't followed this closely, but don't see a problem with not being symmetrical here. The C++ Middleware Writer (CMW) has asymmetric support for Boost Range types: @out (boost::sub_range<std::vector<int32_t> >) If you omit the @out or write @in on that line, the CMW gives you an error message that ranges don't support receive (input) functionality. It only made sense to me to output via a range so that's all that's supported for now. -- Brian Wood Ebenezer Enterprises http://webEbenezer.net I'm happy Adele won all those Grammys. She deserves them them I think.

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Re: [boost] [optional] generates unnessesary code for trivial types
by Andrzej Krzemienski 13 Feb '12

13 Feb '12

> >> Side question: is streamablity going to be in your proposal? > > It is not currently. The reason for that is that there is no clear way how > > it should be implemented (a similar issue applies to pairs, tuples, > > variant, any, etc...) See > > http://lists.boost.org/Archives/boost/2005/03/81619.php<http://www.google.com/url?sa=D&q=http://lists.boost.org/Archives/boost/2005…>for discussion. I > > believe that the problem is with the streaming itself. For instance, should > > streaming out and then streaming the result back in produce the same value? > > Some people expect that, but even std::string could not provide this > > behavior. > > I'd do only << and forget about >> But even that appears like a non-obvious thing to me. Would other people here in the list, and also developers in general agree that it is ok that you have output operation but no input operation? I think that in the standard library they always go in pairs. (I am not sure, though). Also, how would you implement it? what should an uninitialized optional print? Nothing? but how is having printed an uninitialized optional<int> different that not having printed anything? A question mark? but how would the following two be different: optional<string> o1; // uninitialized optional<string> o2 = "?"; cout << o1; cout << o2; If you propose to provide only output operation, then it looks like you want this for some sort of logging. But perhaps it is better to have some overloaded function toString() that converts all the types to strings. Usually the string format that works for one program does not work for the other. And there appears to be no natural/intuitive way of representing any type (like optional) as text. Regards, &rzej

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[1.48.0] Trouble building boost with debug-store=database option (Visual C++ 2010 SP1 64-bit)
by Michael Goldshteyn 13 Feb '12

13 Feb '12

I have always built boost (up to 1.47.0) using the following command line: bjam -j 8 --without-mpi --without-python --build-dir=vc100-bld-64-bit --build-type=complete --toolset=msvc-10.0 architecture=x86 address-model=64 --stagedir=64-bit-vc100 debug-symbols=on debug-store=database stage Now, when I specify the debug-store=database option in the command line above, the build fails and gives me errors as can be seen at the bottom of the following build output excerpt: ----------------------------------------------------------------------------------------------------------------- ...patience... ...patience... ...patience... ...patience... ...found 9190 targets... ...updating 3251 targets... common.mkdir 64-bit-vc100 common.mkdir 64-bit-vc100\lib common.mkdir vc100-bld-64-bit\boost\bin.v2\libs\math\build common.mkdir vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0 common.mkdir vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0\debug common.mkdir vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0\debug\address-model-64 common.mkdir vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0\debug\address-model-64\architecture-x86 common.mkdir vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0\debug\address-model-64\architecture-x86\debug-store-database common.mkdir vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0\debug\address-model-64\architecture-x86\debug-store-database\link-static common.mkdir vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0\debug\address-model-64\architecture-x86\debug-store-database\link-static\runtime-link-static compile-c-c++-pch vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0\debug\address-model-64\architecture-x86\debug-store-database\link-static\runtime-link-static\pch.pch pch.pch.cpp compile-c-c++ vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0\debug\address-model-64\architecture-x86\debug-store-database\link-static\runtime-link-static\assoc_laguerre.obj assoc_laguerre.cpp libs\math\build\..\src\tr1\assoc_laguerre.cpp(6) : error C2858: command-line option 'program database name (/Fde:\dev\devel\libs\boost\boost_1_48_0\vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0\debug\address-model-64\architecture-x86\debug-store -database\link-static\runtime-link-static\libboost_math_tr1-vc100-sgd-1_48.pdb)' inconsistent with precompiled header, which used '/Fde:\dev\devel\libs\boost\boost_1_48_0\vc100.pdb' libs\math\build\..\src\tr1\assoc_laguerre.cpp(6) : error C2859: e:\dev\devel\libs\boost\boost_1_48_0\vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0\debug\address-model-64\architecture-x86\debug-store-database\link-static\runtime-link-static\libbo ost_math_tr1-vc100-sgd-1_48.pdb is not the pdb file that was used when this precompiled header was created, recreate the precompiled header. call "c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\vcvarsall.bat" amd64 >nul cl /Zm800 -nologo @"vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0\debug\address-model-64\architecture-x86\debug-store-database\link-static\runtime-link-static\assoc_laguerre.obj.rsp" ...failed compile-c-c++ vc100-bld-64-bit\boost\bin.v2\libs\math\build\msvc-10.0\debug\address-model-64\architecture-x86\debug-store-database\link-static\runtime-link-static\assoc_laguerre.obj... ----------------------------------------------------------------------------------------------------------------- Is the debug-store=database option no longer supported? Is something else wrong with my build command?

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copy a graph (adjacency_list) to another one
by ShNaYkHs ShNaYkHs 13 Feb '12

13 Feb '12

How can I copy a graph of type adjacency_list to another one graph of type adjacency_list ? Look at the flowing code example: typedef adjacency_list<setS, setS, undirectedS, NodeDataStruct, EdgeDataStruct> MyGraph; MyGraph g1, g2; // processing g1: adding vertices and edges ... // processing g2: adding some vertices and edges ... g1.clear(); g1 = g2 // this gives an execution error (exception) g1 = MyGraph(g2); // this also gives an execution error g2.clear(); Note that to use of copy_graph(...) it is said that the graph type must be a model of VertexListGraph. In my case it is an adjacency_list ... Thanks,

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Re: [boost] [optional] generates unnessesary code for trivial types
by Hite, Christopher 13 Feb '12

13 Feb '12

> On 1.2.2012. 17:53, Hite, Christopher wrote: > > As for the debugger the new C++ allows for a union to contain a > > class. So if a placeholder implemention using such a union would show the data in debug. > But the pointer approach would also work with "real world" compilers > ;) This isn't for science fiction. Gcc says they support n2544 since 4.6. http://gcc.gnu.org/projects/cxx0x.html http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2544.pdf I just tried it out: template<typename T> union placeholder{ T v; placeholder() {} ~placeholder (){} }; ... placeholder<std::string> ps; std::string s("hi"); new(&ps.v) std::string(s); < Uninited happens to contain null. > (gdb) print ps $2 = {v = {static npos = 18446744073709551615, _M_dataplus = {<std::allocator<char>> = {<__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>}, _M_p = 0x0}}} < Initied: > (gdb) print ps $3 = {v = {static npos = 18446744073709551615, _M_dataplus = {<std::allocator<char>> = {<__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>}, _M_p = 0x602028 "hi"}}} I don't know what platform you're using, but it seems completely reasonable to #ifdef a version of the placeholder in that does this so people can debug easily. Does that remove the main reason you wanted a pointer? BTW I did look at your code some. The deconstructor mixin, it's the same technique I used! For the ctor I just define a intermediate class with either default copy and operator= or impled ones. Chris

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Re: [boost] [optional] generates unnessesary code for trivial types
by Andrzej Krzemienski 13 Feb '12

13 Feb '12

> > I am > > thinking of disabling the assignment not because I think it does not belong > > to references, but because there are two ways of implementing it, and > > implementing it either way would surprise a different group of > > programmers. > > And this would be a "run-time surprise". Instead my choice (not necessarily > > the best one) is to provide a "compile-time surprise". > > If value semantics are achievable for this kind of optional, I think > it's better to supply that and let the people who don't expect value > semantics be surprised at runtime. It is very difficult to provide a non-surprising/non-controversial behavior. While I am not happy with my solution, I would also have concerns about "run-time surprise" because: First, there are two ways of implementing optional reference assignment (rebinding or not rebinding) and it seams (from the past discussions in this group) that either is equally counter-intuitive, and it is not clear which one to choose. It would have to be an absolutely arbitrary choice. People are strongly convinced about their views and it is not possible to come up with a reasonable compromise. In fact it is the optional reference assignment that prevented the addition of Optional to ISO C++ the first time (http://lists.boost.org/Archives/boost/2005/10/95120.php) Second, it is difficult to say about value semantics here. References themselves are not really value semantic (at least according to my understanding of the term): they have shallow copy constructor and deep copy assignment. Even if it is disputable for native references, it is more so for optional references, which removes the "special" aspects of references, like extending the life-time of a temporary, reference semantics, or no-storage requirement. We would be building value semantics on a non-value-semantic type. Or in other words, I am concerned that we would only be providing "value-semantics syntax" but not "value-semantics semantics". But we would violate the axioms of value semantic types (like the "separation of the value"). Regards, &rzej

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Boost.Application (Pre Alpha) Release 2 available
by Renato Tegon Forti 13 Feb '12

13 Feb '12

Hi All! There is a new version of "Boost.Application" available in SF (http://sourceforge.net/projects/boostapp/) >> Boost.Application_pre_alpha_2.zip (http://sourceforge.net/projects/boostapp/files/Boost.Application_pre_alpha_ 2.zip/download) This version is based on received comments ! Please, install it: 1) Copy: Boost.Application_pre_alpha_2\boost\application To: boost_1_48_0\boost and, Boost.Application_pre_alpha_2\libs\application To: boost_1_48_0\libs 2) Build (bjam link=shared) . 3) And, to see what has changed, please see the tutorial in help (doc): boost_1_48_0\libs\application\doc\html\application\tutorial.html I will wait for comments! Thanks Renato

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[iostreams] output_filter works only once
by Steven Samuel Cole 13 Feb '12

13 Feb '12

i am trying to use an boost::iostreams output filter to add a string to the beginning and the end of whatever i stream out. my code below works, but only the first time; the second time, the output seems to get lost somewhere, the write method doesn't even seem to get called. i thought at first i'm sending something to the stream that triggers its fail bit, but the stream seems good. the same problem occurs on mac and linux, with latest boost release (1.48) and svn trunk, with cout and a file sink as device. is that a bug ? or am i doing something wrong in my code ? #include <iostream> #include <sstream> #include <boost/iostreams/concepts.hpp> #include <boost/iostreams/device/file.hpp> #include <boost/iostreams/filtering_stream.hpp> #include <boost/iostreams/operations.hpp> using std::cout; using std::endl; using std::streamsize; using std::string; using std::stringstream; class add_string_output_filter : public boost::iostreams::multichar_output_filter { public: template<typename Sink> streamsize write(Sink& sink, const char* s, streamsize n) { string out_string = string(s); // remove trailing '\0' to prevent line break if (out_string[out_string.size()-1] = '\0') out_string = out_string.substr(0, out_string.size()-1); string pre_string("prepended string - "); string app_string(" - appended string"); stringstream sstrm; sstrm << pre_string << out_string << app_string << endl; // TODO: char* to string, back to char* ?!? return boost::iostreams::write(sink, sstrm.str().c_str(), sstrm.str().length()); } }; int main() { boost::iostreams::filtering_ostream out; out.push(add_string_output_filter()); out.push(cout); // string #01 is printed, // string #02 gets lost out << "string #01" << endl; out << "string #02" << endl; }

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BoostCon/C++Now! Talk: How I Code and Why
by Gottlob Frege 13 Feb '12

13 Feb '12

I talked about this last year, and this year I've submitted the proposal, so If you volunteered last year (and are still interested) and/or are interested in helping with a particular/peculiar talk at BoostCon/C++Now this year, then read on, and contact me offline: I'm planning on giving a talk, entitled "How I Code and Why". It is not meant to be presumptuous and tell you how *you* should code, but instead just explains how I code - day-to-day - and how I came to these patterns/conclusions. But who cares just about how *I* code, people want to hear how other members of the Boost community - people they've come to know and respect via the boost lists - code. So I'm hoping to have a few co-conspirators on stage with me, and have each explain a fundamental guiding principle that they follow in their every day code, how they came to adopt this principle and why they find it valuable. For example, I will tell the simple story ('epiphany') of why my favourite comment word is 'otherwise', and how this relates to advice you may have heard or read before. I like the flavour of [ simple, real world, specific ] ---> [ general principle ] The goal is to bring a more real world down to earth picture to the sometimes lofty fundamentals found in books and lectures. Instead of a book explaining how a guiding principle makes sense *in theory*, it would be great (I think) to hear how respected members of the community apply these principles in real life. So, if you want to participate, email me, and we will see what we can figure out. (And/or I might just have to track you down based on promises made last year!) Not sure how many people we need. I'm thinking 5-15 mins per 'principle', and I think you only need to present one (I think the weight of picking *just one* principle makes it all the more interesting). Anyhow, we can work out the details as we go along. Tony PS. this is not (yet?!) an accepted talk, but I have a bit of chicken/egg thing here: ie it would help to have a few people on board to show that the talk is viable, and thus be accepted.

1 0

PCL - Portable C++ Library
by Fernando Pelliccioni 12 Feb '12

12 Feb '12

Hi all, ( Maybe it's an OFF-TOPIC (Sorry) ) At the GoingNative2012 conference, Herb Sutter said that the main disadvantage of C++ today is the lack of a standard library (like dotNet or Java frameworks) He called people to propose additions, like REST Webservices, Async I/O, XML/JSON, ... On the other hand, a member of the public claimed for a desired feature for C++. The answer (can't remember if it was Herb or Bjarne) was to send the paper to WG21 and attend committee meetings to defend his proposal. This is what almost everyone already know about the way WG21 works. I'm not a member of the Committee, or of any company/organization that has an interest in it (Boost, Google, Microsoft, Apple,...) The question is, how I can do to attend meetings? I have no time available or money to pay me the trip myself. Consequently, I see no possibility to attend meetings, then, I have no possibility to defend an idea. Am I wrong? Perhaps this question is for the Committee members (Beman, Dave, Andrew ...) Is there a way to send a proposal and defend it without having to attend meetings? On the other hand, I would like to have access to the discussions (mailing list). or... Is it just for members? Thanks and best regards, Fernando Pelliccioni.

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Re: [boost] [optional] generates unnessesary code for trivial types
by Andrzej Krzemienski 12 Feb '12

12 Feb '12

> I see your point but, IMHO, optional<T&> is too different from normal > references to attempt to draw this association. After all, > optional<T&> is an object in the sense it has internal state and you > can take its address while T& is not (one may call it an alias of an > object). It is therefore logical that optional<T&>::operator= operates > on the object (i.e. on the optional contents) and hypothetical > T&::operator= operates on the referred object. > > Note that if you store a normal reference to int as class member, you > > already have to write your assignment yourself. changing a normal reference > > to an optional reference should not come as something irregular. > > Again, I tend to see optional<T&> as an object, with no apparent > reason why it cannot be assigned to. I understand (I think) your point of view. Let me clarify one thing. I am thinking of disabling the assignment not because I think it does not belong to references, but because there are two ways of implementing it, and implementing it either way would surprise a different group of programmers. And this would be a "run-time surprise". Instead my choice (not necessarily the best one) is to provide a "compile-time surprise". With your view of optional reference (if I got it right it is a pointer with a somewhat different syntax) your expectation of rebinding assignment comes as natural. With a different model of optional reference a non-rebinding assignment comes as more natural. I believe that optional<reference_wrapper<T>> would serve your purpose best. Or would it also introduce the lack of uniformity?

3 3

[optional] generates unnessesary code for trivial types
by Hite, Christopher 12 Feb '12

12 Feb '12

When decompiling my code I noticed a bunch of unnessesary code caused by boost::optional. 1) deconstruction typedef boost::optional<int> optional_int; void deconstruct_boost_optional(optional_int& o){ o.~optional_int(); } One would expect this to do nothing. Instead gcc 4.6.0 with O3 generates: if(m_initialized){ // do nothing m_initialized = false; } 00000000 <deconstruct_boost_optional(boost::optional<int>&)>: 0: 8b 44 24 04 mov 0x4(%esp),%eax 4: 80 38 00 cmpb $0x0,(%eax) 7: 74 03 je c <deconstruct_boost_optional(boost::optional<int>&)+0xc> 9: c6 00 00 movb $0x0,(%eax) c: f3 c3 repz ret This one could be easily fixed by removing the bit that sets m_initialized to false, since we're deconstructing anyway. 2) assignment also generates these problems: void assign_boost_optional(optional_int& o){ o=13; } Here there's a semantic issue: we have to decide to use the copy constructor or operator=. This is also wasteful for POD types or any type which has_trivial_copy<>. 3) Even more expensive is if we want to copy an optional<int> void assign_boost_optional(optional_int& a,optional_int& b){ a=b; } 00000000 <assign_boost_optional(boost::optional<int>&, boost::optional<int>&)>: 0: 8b 44 24 04 mov 0x4(%esp),%eax 4: 8b 54 24 08 mov 0x8(%esp),%edx 8: 80 38 00 cmpb $0x0,(%eax) b: 74 0b je 18 <assign_boost_optional(boost::optional<int>&, boost::optional<int>&)+0x18> d: 80 3a 00 cmpb $0x0,(%edx) 10: 75 16 jne 28 <assign_boost_optional(boost::optional<int>&, boost::optional<int>&)+0x28> 12: c6 00 00 movb $0x0,(%eax) 15: c3 ret 16: 66 90 xchg %ax,%ax 18: 80 3a 00 cmpb $0x0,(%edx) 1b: 74 09 je 26 <assign_boost_optional(boost::optional<int>&, boost::optional<int>&)+0x26> 1d: 8b 52 04 mov 0x4(%edx),%edx 20: c6 00 01 movb $0x1,(%eax) 23: 89 50 04 mov %edx,0x4(%eax) 26: f3 c3 repz ret 28: 8b 52 04 mov 0x4(%edx),%edx 2b: 89 50 04 mov %edx,0x4(%eax) 2e: c3 ret Three possible branches! Theoretically single 64 bit copy do the job. I'm tempted to say: it would be best if for any T has_trivial_copy< optional<T> > iff has_trivial_copy<T>. It might make a sense to make an exception for huge T, where the copying an unused T is more expensive than the branching. 4) has_trivial_destructor<T> should impl has_trivial_destructor< optional<T> > , but this is hard to implement without specialization of optional. Checking has_trivial_destructor might take care of the complexity of optional<T&> since has_trivial_destructor< T& >. I'd be willing to fix #1. The other issues need some discussion. Chris

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Re: [boost] Discovering C++11 lambda argument and result types to construct boost::function
by Andrzej Krzemienski 11 Feb '12

11 Feb '12

> On comp.lang.c++.moderated I talked to Daniel Krügler about how to > discover argument and result types from C++11 lambdas in a template > context. The thread has the title "How to discover argument and result > types from lambda for constructing std::function?" > https://groups.google.com/d/topic/comp.lang.c++.moderated/qaMECIUlJp0...<http://www.google.com/url?sa=D&q=https://groups.google.com/d/topic/comp.lan…> > The task is to provide a function template "make_function" that takes > a C++11 lambda expression and returns a boost::function with the > correct signature to call the lambda. This may be extended to accept > any other callable type. The task you are attempting to solve looks very unusual to me. All the usages of a lambda I encountered so far are that you know the type of a callback in advance and define the lambda so that it matches the signature of the targeted callback. Sorry if this question is silly, but could you give me an example of where this deduction mechanism could be used? Regards, &rzej

2 1

Release testing failures for "tools/build"
by Steve M. Robbins 11 Feb '12

11 Feb '12

Hi, Build/branches/release [1] is failing almost all tests on almost all platforms. I checked several reports and they all point to the following, which should be trivial to fix. reason {{{ unexpected status returned by bjam }}} STDOUT {{{ /Volumes/scratch/kbelco/boost/boost/tools/build/v2/build/project.jam:266: unbalanced parentheses }}} [1] http://www.boost.org/development/tests/release/developer/build.html

1 0

[filesystem.v3] possible bug in replace_extension
by Frédéric Bron 10 Feb '12

10 Feb '12

replace_extension seems to have the wrong behaviour if the provided new extension does not start with a dot. The following program: #include <iostream> #include <boost/filesystem.hpp> int main() { boost::filesystem::path p("foo.bar"); std::cout<<p<<'\n'; p.replace_extension("foo"); std::cout<<p<<'\n'; return 0; } built with the following command line on linux 64 (with boost 1.48.0): $ g++-4.6.2 -DBOOST_DISABLE_ASSERTS -DBOOST_FILESYSTEM_VERSION=3 -DBOOST_FILESYSTEM_NO_DEPRECATED -o toto -I/soft/bal/usr/gcc-release/boost/include toto.cc -L/soft/bal/usr/gcc-release/boost/lib -lboost_filesystem -lboost_system produces the following output: "foo.bar" "foo" but should produce: "foo.bar" "foo.foo" as read from the documentation path& replace_extension(const path& new_extension = path()); Postcondition: extension() == replacement, where replacement is new_extension if new_extension.empty() || new_extension[0] == the dot character, otherwise replacement is the dot character followed by new_extension. Adding the dot before foo makes the program work: p.replace_extension(".foo"); This seemed to work with filesystem v2. Frédéric Bron

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Re: [boost] [optional] generates unnessesary code for trivial types
by Hite, Christopher 10 Feb '12

10 Feb '12

I think paul Fultz wrote: > Actually, you could just take the optional_traits as the first parameter. So you define > optional<T> or optional<optional_traits<my_traits<T> > >. Then optional would be > specialized for optional_traits that will get the user-defined traits. That new optional might break old code: template<typename T> void print(const optional<T>& o){ if(o){ T copy=*o; std::cout<<copy; } } That copy is going to be a optional_traits<>. My method would also force you to add traits to the signature, but at least you wouldn't need to write two specializations: template<typename T,typename Traits> void print(const optional_with_traits<T, Traits >& o); Se have to ask ourselves if configuration is worth it. I think sometimes you don't find that out until it's too late and someone wants a option. Things I can think of making configurable: * bool type - a word might be faster on risk machines * use_trivial_destruction - there might be a case for overridding this * use_trivial_copy - cann't see a case for overriding this * bool_first * alignment - maybe 4 byte alignment is legal but 8 byte is faster * enable_assertions Chris

1 0

How to make tests building faster?
by Mateusz Łoskot 10 Feb '12

10 Feb '12

Hi, I'm trying to figure out if there is anything I could do to improve compile/link-time for tests of Boost.Geometry library. Currently, the tests follow fairly canonical approach in Boost: 1) Each .cpp file defines a single test program and all local test routines are executed from test_main() // test_feature_x.cpp void test1() {} // make use of BOOST_CHECK_* macros void test2() {} int test_main(int, char* []) { test1(); test2(); return 0; } 2) Jamfile per testing project builds and runs each program separately # features/Jamfile.v2 test-suite test-features : [ run test_feature_x.cpp ] [ run test_feature_y.cpp ] ; 3) Root mylib/test/Jamfile.v2 defines testing projects to build and run import testing ; project boost-mylib-test : ; build-project features ; build-project algorithms ; build-project abc ; In total, there are nearly 170 test programs in Boost.Geometry. Obviously, running the whole set of tests (b2 command issued in libs\geometry\test) is time consuming process. I'm wondering if there is any way to reorganise the tests to cut down the build (linking) time. My first idea is to decrease number of run entries (e.g. [ run test_feature_y.cpp ] ) in Jamfiles, by building related tests as single test suite program. Conceptually: [ run test_feature_x.cpp test_feature_y.cpp ] Currently, there is no use of Boost.Test features for tests organisation like BOOST_AUTO_TEST_CASE BOOST_TEST_SUITE etc. I wonder if use of any of the above would help in restructuring tests and decreasing number of programs to build. Another aspect of Boost.Geometry tests I'd like to improve is to improve tests report output. Currently, it is reported as *Passed* or *Failed*. I presume that using Boost.Test to group tests in suits with test cases would improve test report providing details about location of failure (which suite, which case, or even better). I'm looking for any piece of advice on the issues discussed above: - How to cut down build time of tests? - How to improve test output report (and keep it suitable for Boost regression testing framework)? - Is it advised to switch to use Boost.Test features to manage suites and test cases? (I tried to figure it out browsing tests of other libs, but it doesn't indicate any preferred practice). I'd be thankful for any insights. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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Re: [boost] [optional] generates unnessesary code for trivial types
by Andrzej Krzemienski 10 Feb '12

10 Feb '12

> > int i = 1; > > int j = 2; > > optional<int&> oi = i; > > optional<int&> oj = j; > > i = j; > > The effect here is that i remains 1, j remains 2 and oi and oj both hold a > > reference to j. You may find it less surprising but if you think of > > optional reference as a regular reference that is initialized a bit later, > > the behavior is not what you would expect. > > Huh? How does oi come to hold a reference to j? Apologies, I meant to say int i = 1; int j = 2; optional<int&> oi = i; optional<int&> oj = j; oi = oj; Boost.Optional documentation explains it better: http://www.boost.org/doc/libs/1_48_0/libs/optional/doc/html/boost_optional/… Regards, &rzej

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