November 2009 - Boost - lists.preview.boost.org

boost.python problem in release branch (GSoc work)
by Ralf W. Grosse-Kunstleve 13 Nov '09

13 Nov '09

I just found out that two boost.python tests (svn trunk and release) are not valgrind clean. I fear this could be a serious problem, although I've not seen actual failures apart from the valgrind diagnostics. What I know at the moment is: libs/python/test/properties.py libs/python/test/data_members.py produce valgrind errors with trunk revision 56305 but not 56304 (fedora 8 64-bit). The critical revision 56305 is: Merged 2009 GSoC work from sandbox-branches/bhy/py3k branch back into trunk. It is merged into the release branch already. Unfortunately, without revision 56305 boost.python does not work with Python 2.6.3 and 2.6.4, i.e. backing out rev. 56305 and some followup revisions would only replace one problem with another. How far along is the 1.41 release? Is there a chance it could be delayed for a few days? Ralf P.S.: I'll add this issue to the tracker when I get a chance (hopefully tomorrow).

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A fresh approach to iteration (Andrei Alexandrescu)
by Neal Becker 13 Nov '09

13 Nov '09

http://www.informit.com/articles/article.aspx?p=1407357&seqNum=7

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Re: [boost] [msm] Version 2.0 available
by Christophe Henry 13 Nov '09

13 Nov '09

>But you'd have to refactor an equivalent MSM Machine too (you'd need to introduce the flag), right? True, but adding one line to a few states is a lot less work than adding a composite, giving it a transition table and changing the transition table of the state machine.

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Official warnings policy?
by John Maddock 13 Nov '09

13 Nov '09

I'm *not* saying we should do this for 1.41, but should we have an official policy regarding compiler warnings and which ones we regard as "failures"? I realize these can get pretty busy-body at times, but if the user sees several pages of warnings when building Boost it doesn't look so good. So my suggestion would be that we have two test-runners (if we have any spare!) that build with warnings-as-errors, maybe: -Wall -pedantic -Wstrict-aliasing -fstrict-aliasing -Werror For gcc and: /W3 /WX for MSVC? Obviously these may prove to be far too busy-body, but is this worth a try? Cheers, John.

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Re: [boost] GGL Questions
by Bruno Lalande 12 Nov '09

12 Nov '09

Hi Peter, Thanks for your interest in GGL, and for trying to integrate it into your project. Lines and rays don't exist yet in GGL indeed. Adding them would basically consist in defining the corresponding concepts (like for polygon, segment, etc...) and then specialize the distance and intersection (to start with) algorithms for them, which is completely feasible. I'm personnally more video games oriented so I have already thought about the need of such things actually. As for directions, it's not there just because we didn't need it until now (there only exist a notion of orientation for points ranges traversal). I guess it would only be a traits to define and to use in algorithms that needed it. So to summarize, all those things are not yet there, but can easily be added. HTH Bruno

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[iostreams] Is anyone maintaining Boost.IOStreams?
by Richard Smith 12 Nov '09

12 Nov '09

I've just looked through the list of bugs for the iostreams library: https://svn.boost.org/trac/boost/report/14?USER=anonymous&page=4 >From a quick scan, it looks like this library is not being maintained any more. Is this true? Just scratching to scratch the surface, the following dozen bugs seem to be to all be trivial to fix. Many have patches, and the others have a sufficiently clear description that fixing them should only be a couple of minutes' work. 2094 -- has a patch that ought to be uncontroversial 2154 -- relates to code that seems not to exist any longer 2817 -- proposed resolution seems straightforward 2894 -- seems pretty straightforward 2932 -- would be trivial to fix, assuming a fix is desired 3010 -- appears to have been fixed 3011 -- has a patch that ought to be uncontroversial 3197 -- trivial suggestion to remove a compiler warning 3311 -- obviously an error and trivial to fix 3352 -- looks like a genuine subtle bug; includes a patch 3403 -- minor documentation niggle, complete with patch 3505 -- looks a genuine bug and includes patches Some of the other bugs look pretty serious to me, and I might be inclined to spend some time investigating them if I thought there was any realistic chance of the resulting patches being accepted. -- Richard Smith

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[Iostreams] Release notes
by Daniel James 12 Nov '09

12 Nov '09

Hi, I've added some release notes for Iostreams, but I don't really know much about the library so it'd be really helpful if someone who does could take a look at them. http://beta.boost.org/users/news/version_1_41_0 Daniel

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Re: [boost] [msm] Version 2.0 available
by Christophe Henry 12 Nov '09

12 Nov '09

Hi Andreas, >:-) You won't get any flames from me. Yes, I don't agree with some of the >points in MsmSession_Handout.pdf (e.g. 2.4, a user in his right mind would >put Stopped, Open, Paused and Playing into an outer CDLoaded state and then >only say if (state_downcast<const CDLoaded *> != 0)). True, it is a possible solution. But 1) you don't always want to refactor your state machine and 2) sometimes you can't. For example, to take the example in the Statechart documentation(http://www.boost.org/doc/libs/1_40_0/libs/statechart/doc/tuto…, if ( ( state_downcast< const NumLockOff * >() != 0 ) && ( state_downcast< const CapsLockOff * >() != 0 ) && ( state_downcast< const ScrollLockOff * >() != 0 ) ) could have been replaced by if(fsm.is_flag_active<IsOffState,Active::Flag_AND>()). And in this case I don't see a working refactoring solution. In my experience, the flag system has proven invaluable (to define, for example, several success states in a test case defined as a state machine). > However, although I haven't yet reviewed anything in-depth so far, I'm definitely impressed by the progress the library has made. I hope I'll find the time to contribute > an in-depth review. This would be great and your experience could prove invaluable. I'd be very thankful for it. > Out of curiosity, have you made any tests how many states compilers can manage without running out of memory? IIRC, a Boost.Statechart FSM with 128 states > and several hundred transitions was the most I was able to fit into one TU. Good point indeed. There are 2 limitations. First, Msm is based on boost::mpl::vector for the transition table and on boost::fusion::set to contain the states. Both have a default limit of 20, which can be extended to 50. This is the theoretical limit. Of course, you can add some vectorxxx.hpp headers (which I did). I tried up to 80 transitions and 80 states in one machine. The second limitation is the compiler. The test compiles on VC and g++, eventhough you might need lots of RAM (1.4GB with VC9, 400MB with g++) and 40-60s. The execution speed stays the same, thus proving the O(1) double-dispatch. I suppose that, while it must be possible to push this further, Boost.Statechart will likely break the compiler later than Msm. Regards, Christophe Henry

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CGL Questions
by Peter Schregle 12 Nov '09

12 Nov '09

Oops, I meant "GGL Questions" of course.

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CGL Questions
by Peter Schregle 12 Nov '09

12 Nov '09

We are thinking about replacing our geometric algorithms with the ones from GGL. We would want to somehow adapt our own geometric primitives so that GGL can work with them, and with points, line segments and polygons this works rather nicely. However, we also have a few other concepts, where we have not found a simple way to adapt them to GGL. 1) Line We consider a line being an infinite line in the mathematical sense, i.e. it does not have endpoints but extends into infinity on both sides. We want to be able to calculate the distance between such a line and a point, or the point of intersection ot two lines if it exists. 2) Ray We consider a ray being a line with one endpoint or origin, and extending into infinity. Here also we want to be able to calculate the distance between a ray and a point, or between two rays, or points of intersections etc. 3) Direction In order to implement a line and a ray as descibed above, we have introduced the concept of direction (which is basically the same as a direction unit vector, or an equivalent angle). Is there a concept like this in GGL? How could we calculate the angle of a line segment in GGL? Best regards Peter PS: By the way: I find the acronym GGL unfortunate. For me it feels a bit awkward, and I was typing it wrong all the time while preparing this text. Everytime I use it I'm forced to think hard about what it means, in order to get it right. I would prefer a more descriptive name like geometry or geolib, or something else that can be memorized better.

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getting started
by anirvana mishra 12 Nov '09

12 Nov '09

hello everybody, I have been using c++ for quite a long time but never thought of doing some development work for it.But now i think is the high time to contribute to this community and am looking forward for some good development work. can anyone tell as how to get started? Thanks -- All the best.

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Boost.Variant is not EqualityComparable
by brook＠biology.nmsu.edu 12 Nov '09

12 Nov '09

I just ran into the case that Boost Variant does not satisfy the EqualityComparable concept. While it provides operator==() and operator<() (and therefore is LessThanComparable), it does not provide operator!=(), which is required for the EqualityComparable concept. Is this by design or oversight? It seems reasonable to expect that a Boost Variant model this concept, but perhaps I am missing something. In case it is by oversight, the following patch seems to provide the missing operator. Cheers, Brook --- boost/variant/variant.hpp.orig 2009-05-13 21:21:59.000000000 -0600 +++ boost/variant/variant.hpp 2009-05-25 19:21:40.000000000 -0600 @@ -1681,6 +1681,8 @@ return rhs.apply_visitor(visitor); } + bool operator!=(const variant& rhs) const { return !(*this == rhs); } + bool operator<(const variant& rhs) const { //

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On Iteration
by Andrei Alexandrescu 12 Nov '09

12 Nov '09

My article with a draft name "Iterators Must Go (Ahead)" is now published on InformIt and mentioned on reddit.com. Due to the vagaries of posting time and reddit dynamics, the article didn't stay long on reddit's programming page so it got very few views and comments. http://www.reddit.com/r/programming/comments/a2hv3/ Please comment here and/or there and vote up if you liked it. Many thanks to the many Boost participants who reviewed the article prior to publication (see the article's last section for a full list). Andrei

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GGL Extensions
by Tom Brinkman 11 Nov '09

11 Nov '09

>> The GGL team proposes an extension model, very similar to what is used by GIL. I'm not sure that the extensions proposal worked very well for GIL. I'm not sure why. Probably it was too ambitious. Initially, just try encourage a small group of interested developers to work with you on extensions. When that number becomes too large, than start thinking about a more formalized system. If people see that there are a couple of really cool extensions that were intergrated, it might just encourage others to add extensions as well.

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Re: [boost] [msm] Version 2.0 available
by Christophe Henry 11 Nov '09

11 Nov '09

>Apologies if this is a silly question as I'm not familiar with earlier >versions of MSM, but how does this library different from Boost.Statechart? This is not a silly question but one which is begging for controversy ;-) I hope this is not starting a flame war, so from my understanding, there are advantages of using Msm on several points: - speed: Msm is much faster than statechart (see the performance page. Usually more than 20 times faster). - Design: * Msm makes heavier use of metaprogramming = longer compilation, higher speed * No RTTI and no virtual functions * Msm tries to follow the principles of declarativeness described in the book "C++ Template Metaprogramming". This leads to an interface, which is, in my opinion, easier to use. * Again in my opinion, entry/exit/guards are better with Msm. With Statechart, you have to write guard handling yourself and you don't get the event as parameter in the entry/exit. * Actions / guards are more reusable as you can provide a functor object * States are also more reusable as they don't know their containing state machine or other states (due to in-state transition-table definition in Statechart) - UML support. Msm supports forks, UML-conform event dispatching in orthogonal regions (which is that every region gets a chance to handle a given event), entry/exit pseudostates and anonymous transitions (transitions without an event). - Usage: Msm also supports different frontends. For example, eUML tries to hide metaprogramming as much as possible and tries to look like an UML diagram. This also help writing state machines easier with Msm. - Model-Driven approach. You will find in the doc directory my BoostCon paper (the only PDF) where I describe my analysis of MDD with both frameworks. But this is ultimately a matter of taste (as I will of course prefer Msm and Andreas will likely prefer Statechart), and you should take whatever fits your needs better and you are more comfortable with, so I'd advise you to look at both and see what you prefer (and even better, what I could do to improve Msm).

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[1.41.0] Release plans
by Beman Dawes 11 Nov '09

11 Nov '09

The plan to do a Beta 2 has been canceled at the urging of Robert Ramey, Eric Niebler, Paul Bristow, and others. We will stick to more-or-less the same schedule, but do a final release rather than a Beta 2 release. Please complete all merges to branches/release by 9 PM, Friday, November 13th, US Eastern time (02:00, Nov. 14 UTC) That's a day earlier than expected, but will be a lot more convenient for me if we can hold to it. Thanks, --Beman

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[integer] long long warning
by Vladimir Prus 11 Nov '09

11 Nov '09

Hi, if, in SVN trunk as of revision 57535, I go to libs/program_options/test and run: bjam warnings=all cxxflags=-Wextra I get a pile of warnings like this: ../../../boost/integer.hpp:145:24: warning: use of C99 long long integer constant These are actually only warnings that are now printed. Does anybody know what to do with them? Thanks, Volodya

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[BGL] Trying to get a correclty working Parallel BFS code
by Sandeep Gupta 11 Nov '09

11 Nov '09

Hi All, I have spent significant effort on parallel bfs. Currently its almost working. I would really appreciate some help to get it running correctly. I have attached the code (self contained and requires no input file). I think I have followed all the guidelines regarding distributed property maps mentioned in the docs ( http://www.osl.iu.edu/research/pbgl/documentation/graph/breadth_first_searc… ). I am out of ideas of where things can could have gone wrong. The correct output of input graph 0 --> 1 2 1 --> 2 3 2 --> 3 3 --> 4 6 4 --> 5 5 --> 6 --> should be Node ID : Level 0 : 0 1 : 1 2 : 1 3 : 2 4 : 3 5 : 4 6 : 3 But when ran with 2 processes the output comes out to be Node ID : Level 0 : 0 1 : 1 2 : 1 3 : 2 4 : 3 5 : 4294967295 6 : 3 Not sure why this is happening. Any suggestions or pointers would indeed be quite appreciated. Thanks for your time. -Sandeep

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[1.41, thread] small compile fix
by Tim Blechmann 11 Nov '09

11 Nov '09

hi all, trying the lastest release branch, i need the following fix to be able to compile the boost.thread sources ... would be great, if it could make it to the 1.41 release ... thnx, tim diff --git a/libs/thread/src/pthread/timeconv.inl b/libs/thread/src/pthread/timeconv.inl index 5ec3b17..50518c1 100644 --- a/libs/thread/src/pthread/timeconv.inl +++ b/libs/thread/src/pthread/timeconv.inl @@ -6,6 +6,8 @@ // boostinspect:nounnamed +#include <cassert> + namespace { const int MILLISECONDS_PER_SECOND = 1000; const int NANOSECONDS_PER_SECOND = 1000000000; -- tim(a)klingt.org http://tim.klingt.org Relying on the government to protect your privacy is like asking a peeping tom to install your window blinds. John Perry Barlow

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[1.41] cmake references in getting started
by Vladimir Prus 11 Nov '09

11 Nov '09

Hi, I went to fix a broken URL in getting started, and noticed that it now has references to CMake. I have a couple of questions: 1. Why is that reference made inside "Easy Build and Install" section, which was specifically writen by myself to describe the brand new "bootstrap + bjam" procedure? 2. Why is getting started including reference for experimental build system at all? The commit that added this is: r56947 | troy | 2009-10-17 07:33:43 +0400 (Sat, 17 Oct 2009) | 5 lines Replacement for boost.cmake on trunk and release: notices that it exists in the getting started guide. and I don't think the change was discussed. Thanks, Volodya

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Making toolchains easier to use
by Beman Dawes 11 Nov '09

11 Nov '09

I just tried to rebuild the Getting Started Guild on Windows 7, something I had done many times on XP. >cd \boost\trunk\more\getting_started >bjam The build failed. Inspecting the output turned up the message: python: can't open file 'C:/Program Files/Python26/Lib/site-packages/docutils/tools/rst2ht ml.py': [Errno 2] No such file or directory Ah! Because of the Win 7 upgrade, Python was reinstalled, and docutils needs to be installed again, too. Did that, but same problem. Ah! I remember from past pain. The docutils install doesn't install "tools", you have to do that by hand. Did that. That worked. Only half an hour of my time wasted. If I had been a new user or developer, it would have been much longer. Here is what I think should have happened: When the build failed, a dialog box or console message should have popped up telling me that docutils/tools aren't installed, and asking me if I wanted docutils/tools to be installed. If I answered yes, the necessary download and install steps should have been performed automatically. Furthermore, I think the same thing should happen for any tool used by Boost, whether it be for documentation or other purposes. I guess I mean any tool run via bjam, at least at first. This sort of auto install when needed is happens routinely for non-boost apps on my Ubuntu system. It saves much time and aggravation. Thoughts? --Beman

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proposal interval container; ITL moved to the boost sandbox
by Joachim Faulhaber 11 Nov '09

11 Nov '09

Dear boosters, after completion of a lot of boostification work I moved my Interval Template Library to the boost sandbox in the boost project centric form: https://svn.boost.org/trac/boost/browser/sandbox/itl itl boost itl [itl_xt] [validate] libs itl [itl_xt] [validate] I have split up the original library into three parts: (1) itl, (2) itl_xt and (3) validate. Core part 1 'ITL' contains all interval container class templates. Only this part will be prepared for a formal submission. Part 2 'itl_xt' contains extended parts of the original library that do not belong to the core interval container data structures and might be proposed for later extensions. Part 3 'validate' contains the sources for the law based test automaton 'LaBatea' that has been used for an automated check of the ITLs correctness. Parts 2 and 3 do not yet conform boost standards and naming conventions and are not yet intended as contributions to boost. On the core ITL-part I have done the following: + Removed all virtual functions via introduction of mixins + Integrated deeper into boost libraries replacing own code by e.g. boost::type_traits and boost::mpl + Minimized the class template interfaces by transforming member functions into non member function templates. + Made interval containers more interoperable by overloading operators and global function templates. + Wrote a test suite using boost unit test tools. Tested for boost-instance types boost::date_time and boost::rational + Provided jamfiles to build and run examples and tests. + All examples and tests have been compiled, linked and run successfully with msvc_9.0 and gcc_3.4.4(cygwin). Next I am going to write boost style html-documentation. >From the boost web page I don't see a clear recommendation for a preferable way of doing that. Handcoded? Generated with BoostBook? Is there a reference library that has an exemplary standard documentation? Cheers Joachim

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Re: [boost] [msm] Version 2.0 available
by Christophe Henry 11 Nov '09

11 Nov '09

Hi Eric, > Congrats! So is this a review request? Nudge, nudge. :) Yes. As soon as a review date is decided, there will be an announcement. Msm already has a review manager (Dave), we now have a powerful version, we just need a review date. >Do we really need another lambda? I hope that with a proto-based >Phoenix, we can retire all the mini-lambdas that have been >proliferating. (I'm guilty of this, too.) I expected that one :) Right now, yes I need. I need a tool to generate an mpl::vector of transitions (meaning with actions and guards), which I didn't manage to get to work with phoenix (maybe there is a way but I didn't see it). Of course, a proto-based phoenix would be of great help and if needed, I'd be happy to help on this. Regards, Christophe

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GGL Review
by Tom Brinkman 11 Nov '09

11 Nov '09

GGL Review I'm very happy to see that that GGL is now ready for inclusion into boost. I have been following this library for the last couple of years. During that time, I have spent probably 5 hours looking over the code, reading the documentation and compiling the samples. I have a background in GIS applications. Count me as an enthusiastic supporter of this library and as a "yes" vote for inclusion into boost. I have no doubt that GGL will become one of the more popular libraries in boost. Thank you to Barend Gehrels, Bruno Lalande and Mateusz Loskot for submitting it to the public domain and to boost. The samples and tests are thorough and compile without errors or warnings on the latest version of the Intel compiler. The code follows all expected boost conventions. Tom Brinkman

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Confused by regression testing "release" branch summary and unresolved issues
by Phil Richards 10 Nov '09

10 Nov '09

I expect the answer is blindingly obvious, but I've read http://www.boost.org/development/testing.html#Understanding and I don't understand. I'm looking at: http://www.boost.org/development/tests/release/developer/summary.html and: http://www.boost.org/development/tests/release/developer/issues.html I would expect that issues.html would list all the non-expected failures shown in the summary.html page, but it doesn't. (Even tough that's what the "Purpose" seems to claim.) The are a raft of gcc 4.4 failures (not marked as expected - some of them should be, btw), but there are no gcc 4.4 failures at all shown on the issues.html page. What is the relationship between these two pages? Is it documented anywhere? Is it actually an issue that the release has quite a lot of unresolved issues for gcc 4.4? Phil -- Phil Richards, <news(a)derived-software.ltd.uk>

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[gil] Committing some code changes
by Christian Henning 10 Nov '09

10 Nov '09

Hi there, I'm in the process to add some non-invasive code changes for boost::gil. Since this is my first time to commit changes to boost I would like to make sure I'm doing it right. The changes would be added to the trunk. Is that the right place? I have done the obvious steps on my local machine. And besides adding comments when checking in my changes what other steps do I have to do? Thanks, Christian

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Jamfile to control MSVC compiler options /Za and /Ze
by Paul A. Bristow 10 Nov '09

10 Nov '09

I have been taking my own medicine and trying to get Boost.math free of warnings with the /Za No MS extensions option. Mostly this is fine. project : requirements <toolset>msvc:<cxxflags>/Za # disable MS Extensions in Boost.Test. ... But a few tests *require* the extensions. I have tried to enable them for just one module thus: # pow test requires type_of that MS extensions. run pow_test.cpp ../../test/build//boost_test_exec_monitor : # command line : # input files : # requirements <toolset>msvc:<cxxflags>/Ze # Requires type_of which requires MS extensions. : test_pow ; but the compiler complains about deprecation (and most importantly, that later options do not override, so you can't specify /Za and them /Ze. compile-c-c++ ..\..\..\bin.v2\libs\math\test\test_pow.test\msvc-9.0\debug\asynch-exceptions-on \threading-multi\pow_test.obj cl : Command line warning D9035 : option 'Ze' has been deprecated and will be removed in a future release cl : Command line error D8016 : '/Za' and '/Ze' command-line options are incompatible Can any jam experts suggest a way round this (short of leaving the default enable extensions, and making an exception for all the vast majority of modules that are OK with /Za - too tedious to be attractive? Splitting into two classes of tests is also ugly.) Thanks. Paul --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow(a)hetp.u-net.com

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[smart_ptr] make_shared_array/allocate_shared_array function templates
by Roman Kecher 09 Nov '09

09 Nov '09

Hi, I'm suggesting to add the following function templates to allow easy, exception-safe, creation of shared_array objects: - make_shared_array (very similar to make_shared which is used to create a shared_ptr) - allocate_shared_array (again, same functionality like allocate_shared) Is there any reason not to include these? Regards, Roman.

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Time for another bug sprint (after 1.41 ships)?
by Marshall Clow 09 Nov '09

09 Nov '09

Earlier this year, we had a "bug sprint", where many people focused on fixing bugs in Boost. We managed to get the # of open tickets down from 800 to about 720. As of today, there are 820 open tickets in Trac. Is it time to focus on swotting bugs again? 1.41 is scheduled for release on 1-November; that's six weeks from yesterday. How about a bug sprint starting on 14-November, finishing on 22- November? That's two weekends - and finishes up before the American Thanksgiving holiday. -- Marshall P.S. This doesn't mean that people have to wait until November to fix bugs ;-) ;-)

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[function] "paranoia" vs efficiency
by Domagoj Saric 09 Nov '09

09 Nov '09

As far as I can see boost::function<>::operator() performs: if (this->empty()) boost::throw_exception(bad_function_call()); before invoking the stored function (object)... My question is why or why only this "checked"/"safe" approach/method of invocation exists? Because this: - causes (extra) code branching - causes the compiler to insert exception throwing and handling code in surrounding/calling code (which need not otherwise be if the function stored in the boost function instance is itself nothrow) - inserts a call to the bad_function_call constructor - disables the compiler from inlining the function (MSVC atleast) - disables NVRO (MSVC atleast, http://msdn.microsoft.com/en-us/library/ms364057(VS.80).aspx#nrvo_cpp05_top… ) while at the same time I would most often consider calling a "null-function-pointer" a programmer error (that would therefor need to be "handled" with an assert not an exception), not a runtime 'unpredictable' exception... ...IMO the default should be not to include this check (i.e. use an assert) and provide a safeInvoke() type of method for those users and cases that actually require/want this type of check/behaviour... ...or atleast "it would be welcomed" if a non-checking unsafeInvoke() type of method would be provided for those that are 'sure' that the boost::function<> object is valid (for example in the line before i've just performed the same check to decide whether to call the function object or not)... -- "That men do not learn very much from the lessons of history is the most important of all the lessons of history." Aldous Huxley

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[shared_ptr] Set pointer to null
by Mateusz Loskot 09 Nov '09

09 Nov '09

Hi, I'd like to make a custom deleter resetting pointer to 0 or other value (e.g. for debugging purposes) after resource has been deallocated. Would anyone suggest better option to this presented below? struct DeleterT { void operator()(::T* ptr) { ::DestroyT(ptr); // uses Visual C++ specific integer type *reinterpret_cast<__int64*>(&ptr) = 0; } }; Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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[iostreams] building zlib from source
by Vladimir Prus 09 Nov '09

09 Nov '09

I am working on improving detection of external dependencies (for 1.42), and I've noticed that the iostreams library is rather smart when it comes to building zlib (and bz2). It allows the user to specify either: - location of headers and libraries files, or - location of sources for zlib In the latter case, the sources will be compiled automatically. How important is the second use case? It's not very hard to support, and appears handy for Windows users, but if in practice, nobody cares, I can spend the time on other matters. Thanks, Volodya

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[thread] Is interrupting a non boost.thread possible?
by Christoph Mathys 09 Nov '09

09 Nov '09

Hello I've a question about boost.threads: Is it possible to interrupt a thread for which I don't have a thread-object but which is using boost synchronization primitives (mutex, condition)? Thanks! Christoph

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[1.41.0] Beta 2 plans
by Beman Dawes 08 Nov '09

08 Nov '09

Due to the issues exposed in the "Official warnings policy?" thread, there will be a second 1.41.0 beta, tentatively scheduled for Sunday, November 15th. Until Saturday, November 14th, the release branch is open for merges of low-risk bug fixes. In particular, fixes that clear compiler warnings are encouraged. Please do, however, make sure any changes are stable on trunk before merging them to release. I'll be traveling until Monday, with little or no email connectivity. So if questions arise, it would be great if the other release managers could step in with responses. Thanks, --Beman

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ppc64 and OSX Snow Leopard
by Vladimir Prus 08 Nov '09

08 Nov '09

Folks, it was reported that in Snow Leopard, Apple has removed support for ppc64, and folks trying to use that receive fairly obscure errors. Some of Boost users were already confused by this. Now, this is of course more like Apple's problem, but here's a patch, against current trunk, to do a nice diagnostic of this in Boost.Build. The intention is that if you try to build just ppc64, or a two-way fat binary including ppc64 you get an error message, and if you try tobuild 4-way fat binary, ppc64 is skipped and you get 3-way binary. Can some of OSX users apply this patch to trunk and give it a try? If it works, I would like to merge to release branch. Thanks, Volodya

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[1.41.0] Beta 1 release candidate
by Beman Dawes 07 Nov '09

07 Nov '09

1.41.0 beta 1 release candidates are available at http://boost.cowic.de/rc/ Before pushing the beta out to SourceForge, I'd appreciate it if several people would try the release candidate and report success or problems. Thanks, --Beman

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compile problem with thread without rvalue references
by Bob Walters 07 Nov '09

07 Nov '09

I've just attempted a build of the current (1_40_0) boost distribution on a Solaris 10 machine, using the SunStudio12 compiler (cc). There seems to be a problem with boost::thread which is related to this compiler's lack of rvalue references. My build process has been: tar xzf boost_1_40_0.tgz cd boost_1_40_0 export BOOST_ROOT=`pwd` ./bootstrap.sh ./bjam toolset=sun address-model=64 The error I'm receiving: "./boost/thread/detail/thread.hpp", line 344: Error: boost::thread::thread(boost ::thread&) is not accessible from boost::move(boost::detail::thread_move_t<boost ::thread>). 1 Error(s) detected. "CC" -library=stlport4 -xO4 -mt -erroff=%none -m64 -KPIC -DBOOST_ALL_NO_LIB= 1 -DBOOST_THREAD_BUILD_DLL=1 -DBOOST_THREAD_POSIX -DNDEBUG -I"." -c -o "bin.v2/l ibs/thread/build/sun/release/address-model-64/stdlib-sun-stlport/threading-multi /pthread/thread.o" "libs/thread/src/pthread/thread.cpp" move() seems to rely on a copy constructor for its returned thread when rvalue references aren't supported. There is no such constructor. Aside from changing compilers, is there any work around for this?

1 0

[system][filesystem v3] Question about error_code arguments
by Beman Dawes 07 Nov '09

07 Nov '09

A POSIX sub-group is looking at C++ bindings for POSIX. They are talking about a filesystem library binding at least loosely based on Boost.System, Boost.Filesystem, and C++ TR2. In looking at http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2838.html, "Library Support for Hybrid Error Handling (Rev 2)", they are concerned about specifying hybrid error handling like this: void f(error_code& ec=throws()); They would rather see it specified like this: void f(error_code* ec=0); One particular concern is that as currently worded, the N2838 proposal requires throws() return a null reference, which they see as relying on undefined behavior. I wasn't at the meeting where the LWG asked that a null reference be mandated; my reading of the standard is that it is unclear if returning a null reference is or isn't undefined behavior. Some of the core folks seem to think it is undefined, but compilers accept it. Although the reference form is usual for C++, the use of anything other than the default is limited, and usually in low-level code at that. Although I could personally live with either form, I'm leaning slightly toward the pointer form. Regardless, I'd like to hear Boosters views on the two interfaces above. Which do you prefer? Why? --Beman

24 102

[wave][function] Suppressing gcc-4.4.1 warnings
by John Maddock 07 Nov '09

07 Nov '09

Looks like the new type-punning warnings from gcc-4.4.1 are false positives (but I'd like someone else to confirm that!). The fixes below illustrate how to suppress them simply by declaring a temporary variable. HTH, John. Index: boost/wave/util/flex_string.hpp =================================================================== --- boost/wave/util/flex_string.hpp (revision 57230) +++ boost/wave/util/flex_string.hpp (working copy) @@ -1211,7 +1211,10 @@ }; Storage& Data() const - { return *reinterpret_cast<Storage*>(buf_); } + { + Storage* p = reinterpret_cast<Storage*>(buf_); + return *p; + } RefCountType GetRefs() const { Index: boost/function/function_base.hpp =================================================================== --- boost/function/function_base.hpp (revision 57230) +++ boost/function/function_base.hpp (working copy) @@ -316,11 +316,13 @@ new ((void*)&out_buffer.data) functor_type(*in_functor); if (op == move_functor_tag) { - reinterpret_cast<functor_type*>(&in_buffer.data)->~Functor(); + functor_type* f = reinterpret_cast<functor_type*>(&in_buffer.data); + f->~Functor(); } } else if (op == destroy_functor_tag) { // Some compilers (Borland, vc6, ...) are unhappy with ~functor_type. - reinterpret_cast<functor_type*>(&out_buffer.data)->~Functor(); + functor_type* f = reinterpret_cast<functor_type*>(&out_buffer.data); + f->~Functor(); } else if (op == check_functor_type_tag) { const BOOST_FUNCTION_STD_NS::type_info& check_type = *out_buffer.type.type;

6 9

[Boost] Introduction of numeric_adaptor
by Bruno Lalande 07 Nov '09

07 Nov '09

Hi, I would like to introduce the numeric_adaptor library that Barend and I have developed to address a recurring problem: integration of big numbers. We already talked about it in the past, when discussions about geometry would lead to robustness. We're introducing it now because of the upcoming formal review of GGL. The purpose of this library is to turn big-numbers proposed by the most well-known big number libraries into value-types, (almost) usable like any number. This way, a library developer who has a robustness sensible function to write can take numbers as template parameters, and use them in such a way that they can be a fundamental type or one of the value-types provided by numeric_adaptor. This is basically done by: - defining in all the big-number types all the operators needed to manipulate them like fundamental types - defining some free functions in the boost namespace for other operations (sin, cos, hypot, conversions...), which have an default overload for fundamental types and a specific overload for each big-number type proposed Example: template <class T> T my_robustness_sensitive_function(T value) { value /= 2; T value2 = boost::to<T>("123.0123456789"); value += boost::sqrt(value2); return value; }; This function is numeric_adaptor-ready. If T is a fundamental type, boost::to() will forward to boost::lexical_cast and boost::sqrt() will forward to std::sqrt(). If T is one of the big number types provided by the library, specific overloads will be used. The precision of the function will thus entirely depend on the type passed. If the user chooses to sacrifice precision and use fundamental types, there won't be any run-time overhead. If the user wants something more precise and uses a big-number type, the precision of the result will be the one of the chosen type. The library is extensible. Anyone can add a new big number type with all needed operators, and overload the free functions (or specialize a dedicated traits class - see boost::to()). Note: For conversions, we would have liked to extend boost::lexical_cast directly, but the library is not designed in that sense. That's why we wrapped it into a boost::to() function which is explicitly designed to be extended, via traits. Last week on this list list a generic convert_to was discussed and that system could be used alternatively. The library is in the Boost sandbox: https://svn.boost.org/svn/boost/sandbox/numeric_adaptor/ The library currently proposes 2 big number types: CLN and GMP. This is not a formal review request, rather a preview and a reference that we will possibly use during the review of GGL. However, we would really like to have your feedback and to know if such a library would make sense. Regards Bruno

7 13

boost::noncopyable errors are difficult to diagnose on MSVC
by Zachary Turner 07 Nov '09

07 Nov '09

Is there anything that can be done to improve the error messages generated by the compiler when a copy fails to be made due to a boost::noncopyable? I had just finished a sprint where I had typed close to 1,000 lines of code with tons of new classes and objects before trying to compile, and one of the classes I had entered was similar to the following: class foo { public: foo(boost::asio::ip::tcp::socket& socket) : socket_(socket) { } private: boost::asio::ip::tcp::socket socket_; }; Problem here is that I forgot to add a reference to the class member, it was by value so the compiler is going to generate an error since a socket cannot be copied. The error this generated from the compiler was: 1>Q:\include\boost\1.39.0\boost/asio/basic_io_object.hpp(92) : error C2248: 'boost::noncopyable_::noncopyable::noncopyable' : cannot access private member declared in class 'boost::noncopyable_::noncopyable' 1> Q:\include\boost\1.39.0\boost/noncopyable.hpp(27) : see declaration of 'boost::noncopyable_::noncopyable::noncopyable' 1> Q:\include\boost\1.39.0\boost/noncopyable.hpp(22) : see declaration of 'boost::noncopyable_::noncopyable' 1> This diagnostic occurred in the compiler generated function 'boost::asio::basic_io_object<IoObjectService>::basic_io_object(const boost::asio::basic_io_object<IoObjectService> &)' 1> with 1> [ 1> IoObjectService=boost::asio::stream_socket_service<boost::asio::ip::tcp> 1> ] The most I can possibly figure out from this is that it's related to a socket. but this hardly helped as I had been using socket stuff all over the place. It took a long time to track this down because there was zero information about even what source file the offending code was in. I know this is sort of catering to the compiler, but is there any trickery that can be done so that at least the compiler generates an error related to the source file the object was declared in?

4 4

ASIO
by Mohammed Rasmy 07 Nov '09

07 Nov '09

Hello, I am trying to do a POST request using Boost::Asio, of a variable x that holds an email address, and a variable y that holds the contents of a zip file. I couldn't find samples floating around and I'm unsure of how to proceed. I've come up with the following code: boost::asio::streambuf request; std::ostream request_stream(&request); wxString buffer = wxT("POST "); buffer += wxT("http://serveraddress.com"); buffer += wxT(" HTTP/1.1\r\n"); buffer += wxT("Host: serveraddress.com\r\n"); buffer += wxT("Accept: */*\r\n"); buffer += wxT("Connection: close\r\n\r\n"); buffer += wxT("email_address=test(a)test.com"); buffer += wxT("zip_file=")/*actual zip file data here?*/; request_stream << buffer.mb_str(); Note that I am using wxWidgets, wxT is nothing more than a way of defining strings there, and wxString is, well, a string. The above code compiles fine, but I am not sure how to add the zip file? Also would the above code work? I know it is working for a GET request but that's it. Please advise. Thanks for your time, Mohammed _________________________________________________________________ Keep your friends updated—even when you’re not signed in. http://www.microsoft.com/middleeast/windows/windowslive/see-it-in-action/so…

4 4

[smart_ptr] Add make/allocate functions for boost::shared_array
by Roman Kecher 06 Nov '09

06 Nov '09

Hi, I was wondering if there's any reason not to include make_shared_array() / allocate_shared_array() in boost/make_shared.hpp (or maybe add boost/make_shared_array.hpp), along with the already existing make_shared() and allocate_shared() functions? Regards, Roman.

1 0

[swap] ruminations
by Jeffrey Hellrung 06 Nov '09

06 Nov '09

1) Would it be a good idea (aside from breaking backwards compatibility) to insulate boost::swap from being found via ADL? Consider another library, tsoob, which also has a swap intended to be used in the same manner as boost::swap (i.e., it finds a free function swap via ADL, falling back to std::swap or maybe some custom swap or whatever). Now tsoob::swap and boost::swap cannot be used in the same program (ambiguous call to overloaded function swap) if the associated namespaces of the type being swapped includes both boost and tsoob (certainly possible). What I'm thinking about is the possibility of creating a namespace boost::adl which contains (what would have previously been called) boost::swap, as well as any other similar free functions. So the only way to invoke boost::adl::swap is to make it explicit; it will never be found via ADL. Plus it helps document the underlying mechanism (ADL) of boost::swap. 2) Is there some way for boost::swap and tsoob::swap to coexist peacefully while retaining backwards compatibility for both? - Jeff

2 3

[graph] Usage (and possible removal) of LEDA and Stanford GraphBase adaptors for Boost.Graph
by Jeremiah Willcock 06 Nov '09

06 Nov '09

Are there any users of the LEDA and Stanford GraphBase adaptors for Boost.Graph? They are no longer actively maintained and there have been bug reports that the LEDA adaptor does not work with current versions of LEDA. If they are no longer used, Andrew Sutton and I will consider deprecating and/or removing them. Please reply if you would like these components kept in Boost.Graph. -- Jeremiah Willcock

1 0

[random] Seeding again
by Steven Watanabe 06 Nov '09

06 Nov '09

AMDG The attached patch allows random number generators to be seeded with any value. Currently linear_congruential and a few other generators can assert for some seeds. (For instance minstd_rand cannot be seeded with 0). For linear_congruential I am using the algorithm described in n2960, section 26.5.3.1/4. For linear_feedback_shift I use a similar idea, adding 2^(w-k) if the seed is less than 2^(w-k). The behavior of any code that was valid before, should be unaffected by this change. The patch includes test and documentation updates. The tests pass with gcc, msvc, and como. I think it's ready to go now. Okay to commit? In Christ, Steven Watanabe

1 0

New boost packaging suggestion for windows
by Julian Bangert 06 Nov '09

06 Nov '09

Hello, yesterday I tried to download the boostpro binaries for windows and I had to download over a gigabyte to get all configurations for VS 2008. Sadly the version also was outdated and in general not that great ( e.g. Installer quite bad to handle and you have to register to download ) . So I decided to build from source and package it for a few friends who also needed these binaries. I managed to compress boost_1_40 ( no source except headers, no python AFAIK , but everything else you get with a standard build ) from over 900MB down to 37MB by using 7z. I uploaded it here https://obliviononline.com/pub/boost/boost_1_40_0.7z . Should boost use this form of releasing binaries in the future for windows ? Alternatively, you could endorse this form, like boostpro is endorsed right now and I could host it on google code, etc . An easy to set up ( just unzip this file ) binary distribution would make compiling boost-dependent software much easier. I would be willing to distribute future releases compatible with VS 2005 and 2008 in this form. Yours, Julian Bangert __________ Information from ESET NOD32 Antivirus, version of virus signature database 4551 (20091028) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com

12 20

Boost.Python release testing failures
by Steve M. Robbins 06 Nov '09

06 Nov '09

Hi, I'm running Boost nightly regression tests on a 64-bit Debian linux platform for quite some time. I've recently added gcc 4.4 and Boost.Python is failing miserably; c.f. http://tinyurl.com/yl7yjkv If I click on a test result URL, such as for "andreas_beyer" [http://tinyurl.com/yft8k3o] I'm redirected ("See boost/bin.v2/libs/python/build/gcc-4.4/debug") which shows that the compile succeeded, but nothing more [http://tinyurl.com/yft8k3o] Digging into the bjam.log file, it turns out these tests are skipped because the Boost.Python library failed to build. It would be nice to improve the error reporting to make this clear. The compilation error is: "g++-4.4" -ftemplate-depth-128 -std=c++0x -O0 -fno-inline -w -g -fPIC -DBOOST_ALL_NO_LIB=1 -DBOOST_PYTHON_SOURCE -I".." -I"/usr/include/python2.5" -c -o "/home/steve/Packages/boost/upstream/testing/release/results/boost/bin.v2/libs/python/build/gcc-4.4/debug/object/function_doc_signature.o" "../libs/python/src/object/function_doc_signature.cpp" ../libs/python/src/object/function_doc_signature.cpp: In static member function 'static boost::python::str boost::python::objects::function_doc_signature_generator::pretty_signature(const boost::python::objects::function*, size_t, bool)': ../libs/python/src/object/function_doc_signature.cpp:238: error: no match for 'operator%' in '"%s %s(%s%s%s%s)" % std::make_tuple(_Elements&& ...) [with _Elements = boost::python::str&, const boost::python::api::object&, boost::python::str, boost::python::str, boost::python::str, std::string](((const boost::python::api::object&)(& f->boost::python::objects::function::m_name)), ((boost::python::str&&)(& boost::python::str::join(const T&) const [with T = boost::python::api::object_slice](((const boost::python::api::object_slice&)((const boost::python::api::object_slice*)(& boost::python::api::object_operators::slice(const T&, const V&) [with T = int, V = size_t, U = boost::python::api::object](((const int&)((const int*)(&0))), ((const size_t&)((const size_t*)(&(((size_t)arity) - n_overloads))))))))))), ((boost::python::str&&)(&((n_overloads != 0u) ? ((((size_t)arity) != n_overloads) ? boost::python::str(((const char*)" [,")) : boost::python::str(((const char*)"[ "))) : boost::python::str()))), ((boost::python::str&&)(& boost::python::str::join(const T&) const [with T = boost::python::api::object_slice](((const boost::python::api::object_slice&)((const boost::python::api::object_slice*)(& boost::python::api::object_operators::slice(const T&, const V&) [with T = size_t, V = unsigned int, U = boost::python::api::object](((const size_t&)((const size_t*)(&(((size_t)arity) - n_overloads)))), ((const unsigned int&)((const unsigned int*)(& arity)))))))))), ((std::string&&)(& std::basic_string<char, std::char_traits<char>, std::allocator<char> >(n_overloads, 93, ((const std::allocator<char>&)((const std::allocator<char>*)(& std::allocator<char>())))))))' ../boost/python/object_operators.hpp:104: note: candidates are: boost::python::api::object boost::python::api::operator%(const boost::python::api::object&, const boost::python::api::object&) ../libs/python/src/object/function_doc_signature.cpp:249: error: no match for 'operator%' in '"%s(%s%s%s%s) -> %s" % std::make_tuple(_Elements&& ...) [with _Elements = const boost::python::api::object&, boost::python::str, boost::python::str, boost::python::str, std::string, boost::python::str&](((boost::python::str&&)(& boost::python::str::join(const T&) const [with T = boost::python::api::object_slice](((const boost::python::api::object_slice&)((const boost::python::api::object_slice*)(& boost::python::api::object_operators::slice(const T&, const V&) [with T = int, V = size_t, U = boost::python::api::object](((const int&)((const int*)(&0))), ((const size_t&)((const size_t*)(&(((size_t)arity) - n_overloads))))))))))), ((boost::python::str&&)(&((n_overloads != 0u) ? ((((size_t)arity) != n_overloads) ? boost::python::str(((const char*)" [,")) : boost::python::str(((const char*)"[ "))) : boost::python::str()))), ((boost::python::str&&)(& boost::python::str::join(const T&) const [with T = boost::python::api::object_slice](((const boost::python::api::object_slice&)((const boost::python::api::object_slice*)(& boost::python::api::object_operators::slice(const T&, const V&) [with T = size_t, V = unsigned int, U = boost::python::api::object](((const size_t&)((const size_t*)(&(((size_t)arity) - n_overloads)))), ((const unsigned int&)((const unsigned int*)(& arity)))))))))), ((std::string&&)(& std::basic_string<char, std::char_traits<char>, std::allocator<char> >(n_overloads, 93, ((const std::allocator<char>&)((const std::allocator<char>*)(& std::allocator<char>())))))), ((boost::python::str&)(& ret_type)))' ../boost/python/object_operators.hpp:104: note: candidates are: boost::python::api::object boost::python::api::operator%(const boost::python::api::object&, const boost::python::api::object&) ../libs/python/src/object/function_doc_signature.cpp:262: error: no match for 'operator%' in '"%s %s(%s%s%s%s) %s" % std::make_tuple(_Elements&& ...) [with _Elements = boost::python::str, const boost::python::api::object&, boost::python::str, boost::python::str, boost::python::str, std::string, boost::python::str](((const boost::python::api::object&)(& f->boost::python::objects::function::m_name)), ((boost::python::str&&)(& boost::python::str::join(const T&) const [with T = boost::python::api::object_slice](((const boost::python::api::object_slice&)((const boost::python::api::object_slice*)(& boost::python::api::object_operators::slice(const T&, const V&) [with T = int, V = size_t, U = boost::python::api::object](((const int&)((const int*)(&0))), ((const size_t&)((const size_t*)(&(((size_t)arity) - n_overloads))))))))))), ((boost::python::str&&)(&((n_overloads != 0u) ? ((((size_t)arity) != n_overloads) ? boost::python::str(((const char*)" [,")) : boost::python::str(((const char*)"[ "))) : boost::python::str()))), ((boost::python::str&&)(& boost::python::str::join(const T&) const [with T = boost::python::api::object_slice](((const boost::python::api::object_slice&)((const boost::python::api::object_slice*)(& boost::python::api::object_operators::slice(const T&, const V&) [with T = size_t, V = unsigned int, U = boost::python::api::object](((const size_t&)((const size_t*)(&(((size_t)arity) - n_overloads)))), ((const unsigned int&)((const unsigned int*)(& arity)))))))))), ((std::string&&)(& std::basic_string<char, std::char_traits<char>, std::allocator<char> >(n_overloads, 93, ((const std::allocator<char>&)((const std::allocator<char>*)(& std::allocator<char>())))))), ((boost::python::str&&)(&(cpp_types ? boost::python::str(((const char*)"")) : boost::python::str(((const boost::python::str&)((const boost::python::str*)(& ret_type))))))))' ../boost/python/object_operators.hpp:104: note: candidates are: boost::python::api::object boost::python::api::operator%(const boost::python::api::object&, const boost::python::api::object&) ...failed gcc.compile.c++ /home/steve/Packages/boost/upstream/testing/release/results/boost/bin.v2/libs/python/build/gcc-4.4/debug/object/function_doc_signature.o... I hope this helps the Boost.Python maintainers to fix it. Let me know if you need more info. Thanks, -Steve

3 3

[rdb] 0.2.00 - bind parameter and result + dynamic sql
by Jean-Louis Leroy 05 Nov '09

05 Nov '09

I have uploaded version 0.2.01 to the vault. It contains two new major features. The first is the ability to bind parameters to variables allocated outside the prepared statement, e.g.: // in the following examples the database contains: // id first_name name age // 1 Homer Simpson 37 // 2 Marge Simpson 34 BOOST_FIXTURE_TEST_CASE(prepared_select_bind_integer_param, springfield_fixture) { person p; BOOST_AUTO(st, db.prepare(select(p.first_name).from(p).where(p.id == _))); integer id_param; st.bind_parameters(id_param); id_param = 1; BOOST_RDB_CHECK_SELECT_RESULTS(st.execute(), "((Homer))"); id_param = 2; BOOST_RDB_CHECK_SELECT_RESULTS(st.execute(), "((Marge))"); } The possibility of passing parameters to execute() remains but this is more efficient, as execute(params) binds the parameters each time it is called. Likewise, it is now possible to bind results, e.g.: BOOST_FIXTURE_TEST_CASE(prepared_select_bind_results, springfield_fixture) { person p; BOOST_AUTO(st, db.prepare(select(p.id, p.first_name).from(p))); integer id; varchar<30> first_name; st.bind_results(id, first_name); BOOST_AUTO(results, st.execute()); results.fetch(); BOOST_CHECK(!id.is_null()); BOOST_CHECK_EQUAL(id.value(), 1); BOOST_CHECK(!first_name.is_null()); BOOST_CHECK_EQUAL(string(first_name), "Homer"); results.fetch(); BOOST_CHECK(!id.is_null()); BOOST_CHECK_EQUAL(id.value(), 2); BOOST_CHECK(!first_name.is_null()); BOOST_CHECK_EQUAL(string(first_name), "Marge"); } The second feature is dynamic creation of statements. A fully static system doesn't make it possible e.g. to create a search form, where you enter (optional) values and the program returns a list of matching values. Dynamic statement parts (lists of expressions, columns, tables) are created via the make_dynamic() function. It returns a "stable" type, which does not incorporate the full type information for the encapsulated sql code. This makes it possible to create dynamic collections of sql constructs and pass them to a statement. Static and dynamic parts can be miexed freely. For example: BOOST_FIXTURE_TEST_CASE(prepared_select_bind_dynamic_integer_param, springfield_fixture) { person p; dynamic_boolean predicate = make_dynamic(p.id == _); BOOST_AUTO(st, db.prepare(select(p.first_name).from(p).where(predicate))); integer id_param; dynamic_values params; params.push_back(make_dynamic(id_param)); st.bind_parameters(params); id_param = 1; BOOST_RDB_CHECK_SELECT_RESULTS(st.execute(), "((Homer))"); id_param = 2; BOOST_RDB_CHECK_SELECT_RESULTS(st.execute(), "((Marge))"); } Here a dynamic boolean expression is used in the where clause. It contains a parameter so it is necessary to pass a collection of dynamic values when executing the statement. Here is a more complex example: BOOST_FIXTURE_TEST_CASE(prepared_select_dynamic_tables, springfield_fixture) { person p("husband"); person spouse("wife"); partner::qualified link; dynamic_expressions exprs; exprs.push_back(make_dynamic(spouse.first_name)); dynamic_tables tables; tables.push_back(make_dynamic(spouse)); tables.push_back(make_dynamic(link)); dynamic_boolean predicate = make_dynamic(p.id == link.husband && link.wife == spouse.id); BOOST_AUTO(st, db.prepare(select(p.first_name, exprs).from(p, tables).where(predicate))); varchar<30> him; dynamic_values results; varchar<30> her; results.push_back(make_dynamic(her)); st.bind_results(him, results); BOOST_AUTO(cursor, st.execute()); cursor.fetch(); BOOST_CHECK(!him.is_null()); BOOST_CHECK_EQUAL(string(him), "Homer"); BOOST_CHECK(!her.is_null()); BOOST_CHECK_EQUAL(string(her), "Marge"); } Here the projection is partly dynamic, and so is the table list and the where clause. Static entities are checked at compile-time as usual, and dynamic entities at run-time - and thus may fail with an exception. However, the system is designed to (attempt to) minimize the risk of type mismatch in the dynamic parts - no casts are required in client code (nor in the implementation ftm). The test suite contains several other examples of dynamic statements (see test_odbc_dynamic.cpp). At this point I feel that all the major features in the scope of this project have been addressed. Okay a lot is still missing - e.g. more types (currently only integer and varchar are supported), constraints, count() and such functions, group/order by... - but all these should be easy to implement in the existing framework. And the thing needs cleaning up and documentation, plus testing on Unix. J-L

1 0

[filesystem][system] Usage guideline request
by Andrey Semashev 05 Nov '09

05 Nov '09

Hi, I'm updating our software from Boost 1.33 to 1.40 and one of the major issues I encountered is using exceptions from Boost.Filesystem. The exception basic_filesystem_error has changed its interface in a breaking way, as it now relies on Boost.System error codes. I'm not aware of whether this change has been announced properly and the API deprecation period has been offered. And that is actually not what bothers me mostly. The 1.33 version of Boost.Filesystem offered a number of unified error codes that our code used to react accordingly. For example, there were error codes out_of_space_error, already_exists_error, which were used on any platform supported by Boost.Filesystem. Now, with Boost.System in place, there are at least three sets of errors: system::errc, system::windows_error and system::linux_error, although, I assume, the latter is an addition to system::errc. In order to check for the older out_of_space_error I now have to write something like this: catch (basic_filesystem_error& e) { if ( e.code() == system::errc::make_error_code( system::errc::no_space_on_device) #if defined(WIN32) || e.code() == system::windows_error::make_error_code( system::windows_error::disk_full) #endif ) { // out_of_space_error } } Is this the right way to do this? Is there a portable way to do it? I tried to find a better way in the Boost.System documentation, but was highly disappointed as there is virtually no documentation at all. Also, no examples available for this library. I wonder how this library passed the review in the first place.

2 2

[1.41.0] Release branch open for low-risk merges
by Beman Dawes 05 Nov '09

05 Nov '09

branches\release is open for low-risk merges. Use your own judgment as to what "low-risk" is, but as always stability on trunk is one of the criteria. Towards the middle of next week we will take a look at where we stand as far as the freeze for final release. We can always decide to do a second beta, too. But please do any outstanding merges as soon as you are sure they are stable, rather than waiting until the last moment. Thanks, --Beman

3 3

[1.41.0] Release branch closed for all changes; beta RC tomorrow
by Beman Dawes 05 Nov '09

05 Nov '09

The release branch is closed for all changes. Unless someone objects strenuously, I'll build a release candidate for the beta tomorrow (Tuesday) morning, eastern US time. --Beman

8 14

[timer] an accumulating_timer would be nice
by Thorsten Ottosen 05 Nov '09

05 Nov '09

Hi, For some measurements, it would be nice with a timer with the following interface class accumulating_timer { public: accumulating_timer(); // don't start timing void start(); void stop(); double elapsed() const; }; The benefit here would be that we don't have to convert to seconds until that data is actually needed. Thoughts? -Thorsten

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Boost Graph Library license (boost_1_40_0/libs/graph/LICENSE)
by Troels Walsted Hansen 05 Nov '09

05 Nov '09

Hi Doug and boost developers, In a message to this mailing list on 2006-03-12 ( http://lists.boost.org/Archives/boost/2006/03/101902.php) Doug mentioned that the Boost Graph Library had been entirely converted to the regular Boost Software License (http://www.boost.org/LICENSE_1_0.txt) However, even the latest boost 1.40.0 distribution contains a file called boost_1_40_0/libs/graph/LICENSE which contains the text of the old The Boost Graph Library "Artistic License". This is slightly confusing because it could be interpreted to mean that the Boost Graph Library is still covered by the Artistic License. Can you confirm that this file is dead and void? Can it be removed from the boost distribution to avoid any license ambiguity? Thanks, Troels

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Reminder: ** Please don't overquote **
by David Abrahams 05 Nov '09

05 Nov '09

I'm seeing lots of messages that quote entire threads before adding a paragraph (or sometimes just a sentence) out-of-line. Please try to keep the list and its archives readable by pruning the quoted text before posting (http://www.boost.org/community/policy.html#quoting) Thanks -- Dave Abrahams Meet me at BoostCon: http://www.boostcon.com Boost Moderator http://www.boost.org

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Re: [boost] [1.41.0] Beta 1 available
by Vladimir Prus 04 Nov '09

04 Nov '09

Daniel James wrote: > On Wed, Nov 4, 2009 at 1:45 PM, Ovanes Markarian <om_boost(a)keywallet.com> wrote: >> Hello *, >> the link in the docs to Property Tree points to the wrong location. >> http://beta.boost.org/doc/libs/1_40_0/libs/property_tree/index.html >> if changing to http://beta.boost.org/doc/libs/1_41_0/libs and clicking to >> Property Tree the link points to: >> http://beta.boost.org/doc/libs/1_41_0/libs/property_tree/index.html >> But this file does not exist either. > > The documentation isn't uploaded to the site until the final release. > You can see the property tree documentation in the download. The beta > site isn't really meant for general use. Speaking of documentation: 1. It appears that http://www.boost.org/boost-build2/index.html is still broken. Is there any way to figure why? 2. Looking at http://beta.boost.org/users/news/version_1_41_0 I do not see a section 'Build System' -- which is present in boost_1_41_0.qbk Is this expected? - Volodya

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[1.41.0] Beta 1 CMake 1
by troy d. straszheim 04 Nov '09

04 Nov '09

The boost.cmake beta that shadows upstream releases is out. Docs: http://sodium.resophonic.com/boost-cmake/1.41.0.beta1.cmake1/doc Tarballs and zipfiles: http://sodium.resophonic.com/boost-cmake/1.41.0.beta1.cmake1 Followups on the boost-cmake list please. -t

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1.41.0 cmake options
by Neal Becker 04 Nov '09

04 Nov '09

If I wanted to try cmake, can I use cmake with my favorite options? I'm currently using: bjam -sHAVE_ICU=1 -sEXPAT_INCLUDE=/usr -sEXPAT_LIBPATH=/usr/lib64 -- layout=tagged threading=single,multi stage Can I set these options with cmake, and if so, how?

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Re: [boost] New boost packaging suggestion for windows
by Julian Bangert 04 Nov '09

04 Nov '09

Hello, I just noticed an error crept into my earlier posted link: The correct link for google is: http://boost-win-bin.googlecode.com/files/boost_1_40_0-vc9-preview.7z I would appreciate any comments on this distribution, so that I could pack it up with an installer and really "release" it. Again, this distribution pretty much contains all of boost - all configurations for a single version of Visual C++, without Python or MPI, but is very tightly pakced into around 30 MB ( a 30th of the current boostpro distribution size ) Yrs, Julian Bangert

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loglite - A logging library
by JD 04 Nov '09

04 Nov '09

Hello, It's been a while since a discussion about logging hasn't ran on the boost mailing list. I have a small logging library implementing some of the requirements that were previously deemed desirable during the discussion we had here a couple of years ago. Find it here : http://code.google.com/p/loglite/ I've removed all mention to boost in the code, cause I've made some design choice that wouldn't fit with the boost philosophy. Please have a look and let me know what you think could be improved. An example : [example removed because of the now infamous anti-top-posting gmane feature] Regards, JD

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Boost using MS Visual Studio 2010 - C2027
by Christofer Weßeling 04 Nov '09

04 Nov '09

Hi! I've tried to build Boost using MS Visual Studio 2010, but I'm getting a C2027 error. Basically the problem is known and located as a problem of the MS compiler: https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?Feedb… Is there still a workaround? Greets! Christofer Here comes the error....: 1>c:\projekte\boost\1.40.0\boost\bind\bind.hpp(1657): warning C4180: qualifier applied to function type has no meaning; ignored 1> c:\projekte\boost\1.40.0\boost\bind\bind.hpp(1691) : see reference to class template instantiation 'boost::_bi::add_cref<Pm,I>' being compiled 1> with 1> [ 1> Pm=FileTime<UTC> (__thiscall File::* )(void), 1> I=1 1> ] 1> c:\projekte\ps3controlmodule\productformattingasd\fileadmin.cpp(346) : see reference to class template instantiation 'boost::_bi::dm_result<Pm,A1>' being compiled 1> with 1> [ 1> Pm=FileTime<UTC> (__thiscall File::* )(void), 1> A1=boost::arg<1> 1> ] 1>c:\projekte\boost\1.40.0\boost\bind\bind.hpp(1691): error C2027: use of undefined type 'boost::_bi::add_cref<Pm,I>' 1> with 1> [ 1> Pm=FileTime<UTC> (File::* )(void), 1> I=1 1> ] 1> c:\projekte\ps3controlmodule\productformattingasd\fileadmin.cpp(347) : see reference to class template instantiation 'boost::_bi::dm_result<Pm,A1>' being compiled 1> with 1> [ 1> Pm=FileTime<UTC> (__thiscall File::* )(void), 1> A1=boost::arg<2> 1> ] 1> 1>Build FAILED.

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Build boot 1.40.0 on IBM z/OS (EBCDIC)
by norbert.hanke＠bluewin.ch 03 Nov '09

03 Nov '09

Hi folks, I am trying to build boost on the IBM Mainframe on z/OS USS. I successfully modified the jam bootstrap script and have a running bjam binary now. But when trying to build the boost libraries, I get the error below. Does anybody have a hint what to look for? EBCDIC character encoding on my machine might be the reason: digits 0-9 are encoded as character values 240-249, but I have no idea where to start looking. regards, Norbert > ./bjam /home/u250672/boost_1_40_0/tools/build/v2/util/numbers.jam:22: in numbers.check from module numbers error: 03 in 03 1 17 error: is not a number /home/u250672/boost_1_40_0/tools/build/v2/build/version.jam:50: in version-less from module version /home/u250672/boost_1_40_0/tools/build/v2/build/version.jam:102: in version.check-jam-version from module version /home/u250672/boost_1_40_0/tools/build/v2/util/path.jam:172: in join from module path /home/u250672/boost_1_40_0/tools/build/v2/util/path.jam:207: in path.root from module path /home/u250672/boost_1_40_0/tools/build/v2/util/path.jam:247: in path.glob from module path /home/u250672/boost_1_40_0/tools/build/v2/tools/types/register.jam:25: in load from module types/register /home/u250672/boost_1_40_0/tools/build/v2/kernel/modules.jam:283: in import from module modules /home/u250672/boost_1_40_0/tools/build/v2/tools/stage.jam:19: in load from module stage /home/u250672/boost_1_40_0/tools/build/v2/kernel/modules.jam:283: in import from module modules /home/u250672/boost_1_40_0/tools/build/v2/tools/builtin.jam:25: in load from module builtin /home/u250672/boost_1_40_0/tools/build/v2/kernel/modules.jam:283: in import from module modules /home/u250672/boost_1_40_0/tools/build/v2/build-system.jam:11: in load from module build-system /home/u250672/boost_1_40_0/tools/build/v2/kernel/modules.jam:283: in import from module modules /home/u250672/boost_1_40_0/tools/build/v2/kernel/bootstrap.jam:138: in boost-build from module /home/u250672/boost_1_40_0/boost-build.jam:16: in module scope from module

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Temporary objects
by DE 03 Nov '09

03 Nov '09

hi all unfortunately i'm totally out of time now so i only write my proposal and an example forgive me for that the code #include <algorithm> template<typename type> class temporary : public type { temporary() : type() {} temporary(temporary &a) : type() { using std::swap; swap(static_cast<type&>(*this), static_cast<type&>(a)); } template<typename other> temporary(const other &a) : type(a) {} temporary &operator=(temporary &a) { using std::swap; swap(static_cast<type&>(*this), static_cast<type&>(a)); return *this; } template<typename other> temporary &operator=(const other &a) { type::operator=(a); return *this; } }; example1 temporary<huge_type> foo(const huge_type &a) {//returning temporary object temporary<huge_type> ret; //or even 'ret(a)' //doing something... return ret; } //... huge_type result; result = foo(bar); //somewhere in code only one copy operation -- assignment operator return by value copying overhead is eliminated with help of swap() example2 struct my_type { //... my_type(temporary<my_type> &a) { this->swap(a); } //... my_type &operator=(temporary<my_type> &a) { this->swap(a); return *this; } //... }; temporary<my_type> process(const my_type &item) { temporary<my_type> ret; //processing item... return ret; } //... my_type result = process(item); //somewhere in code //or result = process(item); no temporary object handling overhead at all return by value, copy-construct and assign from temporary objects for free! thank you for attention

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[interval container (itl)] A pretty large bitset
by Joachim Faulhaber 03 Nov '09

03 Nov '09

Dear list! In thread http://lists.boost.org/Archives/boost/2009/06/152786.php Zachary Turner posted an article about a compressed bitset, that uses run-length defined intervals to achieve a compact representation of large bitsets that are useful for managing huge file allocation tables. As I mentioned in a reply to this article, Zach's compressed bitsets, in their basic ideas, are quite similar to itl::interval_sets: They allow for compression of large quantities of elements as long as they occur in (large) uninterrupted chunks. As Zach pointed out, this nice behavior is completely spoiled, if we would want to handle a set like {1,3,5,7,9,...,2(k-1)} or as bitset '0101010101...01' Here, the capability of usual bitsets to compress elements that are distributed over only small ranges can neither be applied to Zach's compressed bitset nor to an itl::interval_set of the Interval Template Library. As a new use case of interval containers I have developed a *large_bitset* class template on top of itl::interval_map that is able to combine interval compression *and* bitset compression. It is, for instance, capable of representing the bitset mentioned above '01010101...010' a b a: bit 0 b: bit 2^64-1 containing 2^63 bits (or elements) with just *one* internal interval associated to only *one* value of 64bit length ;) Curious?? Find the documented example code in my updated library docs at http://www.herold-faulhaber.de/boost_itl/doc/libs/itl/doc/html/boost_itl/pr… While the documented class template 'large_bitset', for reasons of a short presentation, is only a minimal one, you can find a more elaborated version as 'interval_bitset' in the sandbox at https://svn.boost.org/svn/boost/sandbox/itl/boost/itl_xt/interval_bitset.hpp I'd like to ask Zachary Turner to comment on the use case. Can this be useful in your field? Moreover I'd like to encourage everyone to give feedback on my interval container library, report problems, bugs and share suggestions. If you find this stuff useful please volunteer as review manager for the submitted library Boost Interval Containers. Note, that the new example on 'large_bitsets' is not yet included in the library submitted for review in the vault but it is contained in the sandbox. I am currently preparing an update of the review version of the itl, that is adjusted and corrected for the feedback, suggestions and patches that I have received during the last weeks. I will integrate further feedback and account for bug reports if you have any. Best regards Joachim

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[tree?] STL like tree data structure in boost?
by Nil Geisweiller 03 Nov '09

03 Nov '09

hi, any idea if there is in boost a similar tree data structure such as Kasper Peeters's tree.hh http://tree.phi-sci.com/ ? thanks Nil

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Parallel Tree Merge
by Biddiscombe, John A. 03 Nov '09

03 Nov '09

If I have a representation of a tree and I have sub-portions of it spread across a number of processes (but the whole tree represents a well-formed and simple tree structure). Is there a reasonably straightforward way of doing this using BGL or PBGL. I had hoped that it might be as simple as defining some templated tree structure and using the add operator after gathering pieces onto one node. (The tree structure could be represented as XML where the root would exist on all processes, different sub-nodes and leaves and would occur on different processes - a simple xml merge would probably suffice for my needs right now). If examples using boost libraries ((p)BGL/MPI) or other similar combination exist and anyone can point me to resources I'd be most grateful. (I'm not an expert with BGL so will need some do some learning...) Thanks JB -- John Biddiscombe, email:biddisco @ cscs.ch http://www.cscs.ch/ CSCS, Swiss National Supercomputing Centre | Tel: +41 (91) 610.82.07 Via Cantonale, 6928 Manno, Switzerland | Fax: +41 (91) 610.82.82

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Cross-platform date/time problems
by Zachary Turner 03 Nov '09

03 Nov '09

Hello list, Apologies for the cross-posting, this originally went to the boost-users list but it got no responses, and then I also realized it was actually more appropriate here. Suppose I have a cross-platform agent that communicates with a server. Agent from platform X sends a message to the server which contains a date/time. Server sends a message to another agent running platform Y with the same date/time. In practice X/Y are always either windows/linux or linux/windows. The server always tells the agent which platform's native format the time is represented in, so there should be no problem. Ideally I'd like to write the following code: ptime time; if (msg.is_from_windows()) { time = from_ftime<ptime>(msg.time()); } else { time = from_time_t(msg.time()); } But this doesn't work because from_ftime<> is not defined on linux. If from_ftime<> is already templated on the FILETIME type, is there any reason it needs to be #ifdef'd out on non-windows platforms? I mean, a FILETIME is really just a uint64, can't the templated function also just operate on a boost::uint64_t? Zach

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#3541 Support <boost/ptr_map.hpp>
by Olaf van der Spek 02 Nov '09

02 Nov '09

Hi, https://svn.boost.org/trac/boost/ticket/3541 Could a forward header file be created such that #include <boost/ptr_map.hpp> works? The extra ptr_container directory is hard to remember..., I always have to look it up. boost/ptr_* looks much more natural. Greetings, Olaf

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Re: [boost] loglite - A logging library (JD) (Zachary Turner)
by Tan, Tom (Shanghai) 02 Nov '09

02 Nov '09

>I've always found it was easiest to do something like: >namespace boost { namespace filesystem { >#if defined(_WIN32) || defined(WIN64) > typedef wpath npath; >#else > typedef path npath; >#endif >} } >and then use boost::filesystem::npath everywhere. Performance isn't >generally the bottleneck when dealing with the filesystem, but why even >bother with so many behind-the-scenes conversions when you can just as >easily store everything in the type the O/S is expecting in the first place >with a simple typedef? That's handy when only OS API is involved, but if you have to use it other Libraries which are only string-ready, e.g. LIGLITE, you have no choice. Even Some popular Boost libraries are only for strings, Boost.Test is one.

1 0

The C++ Post-Processor
by Christian Schladetsch 02 Nov '09

02 Nov '09

Hello, This is a general post about C++. Why is it that the pre-processor (PP) is the source of so much disdain, and yet it is the first resource exploited to 'fix' problems with C++? Why has the PP received so little attention over the years, from its early use as M4? This is a message to the powers that be: the PP is a powerful tool. It provides a 'context-cutting' mechanism for creating and extending solutions. It is a true "meta-programming" system built right into C++. No other language I can think of has a PP. This is often viewed as being a good thing, but I wonder more and more as I get older that a good PP is in fact needed to span some otherwise very difficult boundaries. Other languages are "dynamic" inasmuch as they reflect classes and allow for runtime changes to types and instances. I think we all here agree that this ability is counter to building firm, safe and efficient software. But the PP is similar to that, allowing a degree of dynamicy not otherwise available. Specifically, by exposing concepts to the PP we can leverage reflection and synthesis while building on inheritance and conglomeration. I don't have a point as such; I just wanted to raise the idea of developing M4 and the PP past where it is. There is a lot of low-hanging fruit there. This is evidenced by the fact that a lot of other languages are or can be transliterated to C++. Rather than thinking of C++ as the output, we could be thinking of C++ as the input. Perhaps a way forward for C++ is a good PP and a standards-based implementation of C++ in C++ so it can embed itself. I've written a number of languages, and in each I've had to address the issue of pre-processing. The latest attempts have resulted in a system where it parses and executes via AST input to produce an output that is then parsed by the same system to produce an AST that is then walked to eventually produce machine code. I think this model is best, and would be delighted to see some similar movements in the PP/C++. We have Boost.Wave to start with... Why not give it real Expressions? Loops? Scopes? Classes? Templates? memory management? IO? Is there any interest in a Boost.C++ ? Regards, Christian

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[optional] layout
by Domagoj Saric 01 Nov '09

01 Nov '09

why is boost::optional laid out so that the bool comes before the object's placeholder/storage? this takes up to 7 extra bytes of storage with default alignement and, more importantly, it forces pointer offset adjustment/calculation when accessing a boost::optional<> through a pointer (and trying to access the actual contained object)... it also makes life harder for those of us keen to hackery ;) because it makes the address of an optional different from the address of the actual object within the optional... ps. it would be 'cool' if all of the functionality from boost::optional<> not related to the 'is initialized' bool (conditional destruction, etc...) could be extracted into a separate class (usefull for cases where you have to delay/in-place construct an object but are certain that you will construct it by the point where it needs to be used or destroyed...so you do not need the 'conditional' overhead)... -- "That men do not learn very much from the lessons of history is the most important of all the lessons of history." Aldous Huxley

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Re: [boost] loglite - A logging library (JD)
by Tan, Tom (Shanghai) 01 Nov '09

01 Nov '09

> Please have a look and let me know what you think could be improved. The first thing I notice is that it does not support std::wstring directly. It's a big problem in my case I use wide-character in all my applications, which simplifies dealing with UTF-16 adopted by Modern Windows platforms. If I need to any string info from my program, I'll have to convert from UTF16(represented as std::wstring) to UTF8 so that it could be working well with LOGLITE. That's inconvenient. Offtopic, I am expecting boost::filesystem V3 for this very same reason.

3 2