- Boost - lists.boost.org

Ann: Floating Point Utilities Review starts today
by John Maddock 03 Mar '08

03 Mar '08

The review of Johan Rade's floating point utilities starts today. Code and docs can be downloaded from : http://www.boost-consulting.com/vault/index.php?action=downloadfile&filenam… The library consists of three parts: 1) Floating point classification routines: these are optimised implementations of the C99 and C++ TR1 functions fpclassify, isinf, isnan, isnormal and isfinite. From Boost-1.35 onwards these are already a part of Boost.Math (see http://svn.boost.org/svn/boost/trunk/libs/math/doc/sf_and_dist/html/math_to…) so if accepted the two implementations will get merged. The review here should focus on the implementation used, and testing on whatever platforms you have available - in particular are there any circumstances (compiler optimisation settings etc) where this implementation breaks? 2) Sign manipulation functions: implementations of the C99 and C++ TR1 functions copysign and signbit, plus the changesign function. Two of these (signbit and copysign) are currently undocumented members of Boost.Math, and again the two implementations will get merged if this library is accepted. Again the main focus of the review here is the implementation, and testing thereof especially in the presence of compiler optimisations. 3) C++ locale facets: these will read and write non-finite numbers in a portable and round-trippable way: that is not otherwise possible with current C++ std library implementations. These are particularly useful for number-serialisation for example. Since the design is already specified by the C++ standard for these facets, your review here should focus on implementation, testing, documentation, and perhaps where in Boost these should best be placed if accepted. These look to be a useful collection of utilities, so I'll look forward to your reviews, Regards, John Maddock, Floating Point Utilities Review Manager.

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"Component-based" library (request for critique)
by Jo�o Henriques 03 Mar '08

03 Mar '08

Hi there, I haven't posted to the boost mailing lists except for the Spirit group, but I've been a user for some time. I'm still not sure if this is the right place to post this. The main reason why I came to this list is that I need some real critique on this library of sorts and if you think it's good enough, it might be submitted as an actual addition to boost. What scares me the most is the huge amounts of "boostification" that it probably needs, but I'm willing to give it a try. For those not familiar with component-based design, it can be put very simply as a "programmer-friendly" form of multiple-inheritance: we want to build classes using different components, worrying as little as possible about the specific details of these components. The fact that a class has a specific component is also not known in advance, but user code must be able to access any component-based class through the same interface. The simplest piece of code can produce this effect: class ComponentA { public: int x, y; }; class ComponentB { public: int i; }; class Entity { public: virtual ComponentA* a() { return 0; }; virtual ComponentB* b() { return 0; }; }; class Ent1 : public Entity { public: ComponentA _a; ComponentA* a() { return &_a; }; }; class Ent2 : public Entity { public: ComponentA _a; ComponentA* a() { return &_a; }; ComponentB _b; ComponentB* b() { return &_b; }; }; Ent1 only uses ComponentA, so ent1.b() returns a null pointer. In a more pratical example, many "virtual components" would be defined in the base class Entity, but only a handful would be overrided by the derived classes and actually used. Treating an instance as the base class, it's easy to inspect whether it has a given component or not. No downcasting is ever needed. The inclusion of each component as member instead of taking the multiple-inheritance approach avoids any name conflicts and "ambiguous usages"; so a component can be written as a self-contained class, not worrying about the outside world at all. I realize this example is trivial and anyone could come up with a similar system on their own. What interests me is the sistematic usage of this technique and the definition of a common interface that turns each of these definitions into a one-liner. The most useful implementation of these ideas allows "dynamic components" on top of the ones burned into a derived class, and any component at all can be enabled or disabled (with relevant constructors/destructors called), without any knowlege of whether it's dynamic or permanent. Accessing dynamic components incurs some overhead, but for the other ones it is the minimum possible. So, in conclusion, I'd like to know what you think. Maybe this is a trivial system not good enough to be called a "library", maybe it's useful but not Boost material, or maybe you think that after some work it could be a nice addition. What I want is some critique. If you think it's worthwhile, I can provide the final code (with dynamic entities and all) for you to review. João Henriques

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Trac open bugs - by assignee
by Marshall Clow 03 Mar '08

03 Mar '08

[ 219 open bugs today, 218 Friday ] If you are maintaining a library, and have not logged into the trac system at <http://svn.boost.org/trac/boost/>, please do so ASAP. Until you do that, no tickets can be assigned to you, and will remain under "None". Instructions on working with tickets can be found at: <http://svn.boost.org/trac/boost/wiki/TicketWorkflow> and a mapping of user names to "real names" can be found at: <http://svn.boost.org/trac/boost/report/16> Bug summary 23 djowel 19 az_sw_dude 14 grafik 13 dgregor 12 vladimir_prus 12 doug_gregor 12 dave 11 agurtovoy 10 no-maintainer 9 bemandawes 8 anthonyw 7 jsiek 6 turkanis 6 johnmaddock 5 witt 5 igaztanaga 4 ebf 3 t_schwinger 3 ramey 3 eric_niebler 3 danielw 2 shammah 2 rogeeff 2 pavol_droba 2 nasonov 2 matias 2 kaalus 2 jmaurer 2 hkaiser 2 danieljames 2 aaron_windsor 2 None 1 urzuga 1 speedsnail 1 samuel_krempp 1 pdimov 1 nesotto 1 marshall 1 hljin 1 garcia 1 dlwalker None 1493 SVN files making it through to install None 1644 Boost.Test missing documentation file BOOST_CHECK_CLOSE_FRACTION.html aaron_windsor 1622 Adjacency list needs to handle self-edges correctly aaron_windsor 778 top-level configure is broken agurtovoy 1001 gcc 4.1.2 segfaults on mpl/test/apply.cpp agurtovoy 1051 MPL header ordering triggers bug agurtovoy 1099 unable to iterate through a "non-explicitly-declared" mpl::set agurtovoy 1215 Boost 1.34.1_ mpl: Wrong workaround detection using MinGW32 (or.hpp_ line #33) agurtovoy 1317 has_xxx randomly broken in msvc agurtovoy 1469 [mpl] nested typedef of set has two different meanings agurtovoy 1476 always<> is not nullary. agurtovoy 1528 g++ 4.3.0 reports error because of redeclaration of next agurtovoy 1549 Boost.MPL: 'index_of' algorithm is not documented agurtovoy 1568 duplicate include guards agurtovoy 588 mpl::remove compile error with gcc 4.1.0 anthonyw 1154 tss destruction segfaults in conjunction with dlopen/dlclose anthonyw 1168 [thread] tss crashes randomly anthonyw 1268 xtime_cmp changes to deal with overflow were reverted anthonyw 1470 Boost.Thread: Compilation errors with non-__cdecl calling convention anthonyw 1640 [Thread] warnings from VC9 + warning level 4 anthonyw 1657 Bug in boost::threads sample anthonyw 876 xtime documentation incomplete anthonyw 881 errors when build with Apache stdcxx az_sw_dude 1028 typo in boost header: date_time/time_defs.hpp az_sw_dude 1078 from_iso_string cannot read the output from to_iso_string az_sw_dude 1098 Urgent libboost-date-time1.33.1 : bugs on ia64 ? az_sw_dude 1147 date_time library contains global #define ERROR az_sw_dude 1160 warning: month_format shadows a member of this az_sw_dude 1162 warning: ticks shadows a member of this az_sw_dude 1289 posix_time::time_facet forgets to pass a_ref argument to base class az_sw_dude 1299 change in typedef stringstream_type in format_date_parser.hpp causing compilation error az_sw_dude 1306 invalid docbook in date_period.xml az_sw_dude 1384 Linking problem with date_time library on Visual C++ 2008 Express az_sw_dude 1386 date_time documentation Jamfile breaks building of boost docs az_sw_dude 1524 format_date_parser.hpp(221) : cannot convert parameter 1 az_sw_dude 1574 operator<< for boost::posix_time::ptime ignores ostream flags az_sw_dude 287 wrong usage of ios_base::narrow az_sw_dude 316 date_time type conversion warning az_sw_dude 604 from_ftime incorrectly processes FILETIME filled with zeros az_sw_dude 642 operator<< for gregorian::date_duration not found az_sw_dude 889 Insane Dependencies az_sw_dude 890 date_time library supports only the current dst rule bemandawes 1378 filesystem path invalid name for hidden files (LINUX) bemandawes 1389 filesystem::ostream << boost::format generates operator ambigious error (in MSVC++) bemandawes 1458 Darwin Tiger throws std::runtime_error: locale::facet::_S_create_c_locale name not valid bemandawes 1578 bug in readdir_r_simulator() in a multi-threaded environment bemandawes 1583 Serious flaw in boost::filesystem filename handling (opensuse) bemandawes 1589 [filesystem] 'mbstate_t' : is not a member of 'std' bemandawes 1606 filesystem/src/exception.cpp doesn't build with gcc bemandawes 1613 Link Errors against file_system on OS X with Intel Version 10.1 C++ compilers bemandawes 752 directory_iterator doesn't work with catch danieljames 1554 When BOOST_HASH_NO_EXTENSIONS is defined hash doesn't support new string types. danieljames 1555 When BOOST_HASH_NO_EXTENSIONS is defined hash doesn't support boost::system::error_code danielw 1044 Argument pack inaccessable in a functions return type danielw 1054 Parameter takes an "infinite" amount of time to compile with the Intel compiler. danielw 1097 keyword.hpp generates many warnings C4180: qualifier applied to function type has no meaning; ignored dave 1010 linking boost.python on freebsd dave 1019 iterator_facade::pointer should be the return type of operator-> (DR 445) dave 1085 Python rules for compiling in Mac OS X dave 1179 [boost.python] can not export a union in VC2005sp1 dave 1181 [boost.python] can modify enum value dave 1387 Review / update docs to reflect changes dave 1460 Python classes with multiple bases are convertible only to the first class in the lists dave 1482 boost::python::throw_error_already_set should be marked noreturn dave 1516 [python] Failing VC9 regression tests dave 1599 [python] '_set_se_translator': identifier not found dave 865 Use of C++0x keyword as identifier dave 910 gcc strict-aliasing problems with python dgregor 1164 Floyd Warshall broken with unsigned edge weights dgregor 1192 [boostbook] problem when two files have the same name dgregor 1199 configure doesn't work with path containing whitespaces (MacOS X) dgregor 1310 [result_of] const-qualified function pointer doesn't work dgregor 1326 Unable to check graph isomorphism using LEDA adapter dgregor 1391 dominator_tree_test on Borland/CodeGear outputs overly long line dgregor 1394 Translate libs/graph/build/python/Jamfile to BBv2 dgregor 1395 Write Tests for Python Bindings dgregor 1630 gcc-4.3: adjacency_list.hpp includes deprecated header dgregor 1655 Documentation of the depth_first_search() Function dgregor 556 Bundled graph properties dgregor 732 Johnson All-Pairs needs better "no path" information dgregor 736 Const correctness violation djowel 1170 Emit Warnings instead of # symbols in the syntax highlighter djowel 1171 Quickbook title output djowel 1172 non-utf djowel 1176 Space after inline code djowel 1206 Escaping from within code? djowel 1273 CR+LF newlines in position_iterator djowel 1276 spirit problem with _GLIBCXX_DEBUG djowel 1277 Closing section like [pre with } causes Quickbok to crash djowel 1280 sections in imported source files get put inside <para> elements in docbook output djowel 1281 Quickbook produces invalid BoostBook/DocBook XML djowel 1324 tuple should have a swap() that operates element-by-element djowel 1396 wrong result_of invocation around transform_view djowel 1436 [quickbook] inline code inside headings djowel 1484 Quickbook produces illegal docbook for some docinfo fields. djowel 1500 [Spirit/Phoenix] C4512 Compiler warnings from VC8 djowel 1570 Some boost headers aren't ready for gcc 4.3 djowel 1600 duplicate include guard djowel 1601 distane of boost::tuple djowel 1607 Tuple Library Documentation Changes djowel 1610 [MSVC/STLport] [tree/common.hpp] Standard library requirements violation(incomplete type as vector parameter) djowel 1614 vector workaround needed for MSVC9 djowel 1617 spirit gcc-4.3 fix djowel 1619 [Fusion] C4512 warnings from VC9 (Visual Studio 2008) dlwalker 613 boost/crc.hpp uses non-standard conforming syntax doug_gregor 1021 [Graph][reverse_graph] Problem using reverse_graph adapter with an adapted user defined graph doug_gregor 1076 compile error: disconnecting struct with operator()() doesn't work in VS2005 SP1 doug_gregor 375 LEDA graph adaptors do not handle hidden nodes properly doug_gregor 402 random_vertex/random_edge are unnecessarily inefficient doug_gregor 403 Document copy_component doug_gregor 447 reverse_graph and constness of property maps doug_gregor 708 Dijkstra no_init version should not require VertexListGraph doug_gregor 733 Numbered headers don't work with "preferred" syntax doug_gregor 735 Fruchterman-Reingold grid performance can be improved doug_gregor 738 Memory leaks with signal::connect? doug_gregor 829 Implicit graph not implement doug_gregor 852 Problem with Boost and GCC 4.1 ebf 1507 [variant] C4512 warnings from VC8.0 ebf 1548 [variant][docs]typo: formal arg_ operand_ should be v in times_two arglist ebf 1654 recursive variants do not handle nested variants correctly. ebf 993 Variant should use least common multiple of alignments_ rather than maximum eric_niebler 1631 [accumulators] compiler warnings with VC9 + warning level 4 eric_niebler 1650 Accumulators conflicts with interval eric_niebler 1652 foreach + this keyword -> fails under MSVC garcia 1581 Boost.MultiArray: Resizing bug if the index is not 0-based grafik 1041 Cygwin requires PATH setting. grafik 1322 trac rejects patch attachment as spam grafik 1417 Regresson tests hang in Darwin (Tiger) grafik 1430 Regression fails under Cygwin grafik 1433 Trac's spam detection rejects too many valid messages grafik 1512 Broken link to vacpp in bjam docs. grafik 1513 Broken link to bcpp in bjam docs. grafik 1571 boost bugtracker displays a patch incorrectly grafik 1576 cannot read non-ASCII output messages grafik 1577 Some commands don't work because hStdInput == 0 grafik 1663 build.bat cannot set/reset ERRORLEVEL grafik 616 Boost Jam_ and non english directorys grafik 959 linking fails when Boost is compiled with STLport 5.1.* on Linux (names mismatch) grafik 986 Problem building Python modules on boost 1.34.0 hkaiser 1079 boost-1.34.0 fails to compile. concept checks not satisfied. hkaiser 1603 Compile Error: cpp_expression_value.hpp - is_int_ is_bool_ is_uint undeclared hljin 1522 bit_range friend decl in bit_aligned_pixel_reference.hpp needs to be fully qualified for gcc 4.3 mainline igaztanaga 1080 boost::interprocess win32 global file mapping issue igaztanaga 1210 interprocess::barrier hangs during second use under linux (boost 1.33.1) igaztanaga 1390 Interpocess: managed shared memory failing completely under OS X igaztanaga 1634 boost::interprocess::vector cannot contain volatile int igaztanaga 1635 Incomplete include guard in boost/intrusive jmaurer 351 Diff in state of mersenne_twister gen between GCC3.41 & CW9 jmaurer 599 uniform_01 copies engine instead of using a reference johnmaddock 1081 Empty string rejected as perl-style regex johnmaddock 1314 Using SSE-intrinsics in VC8 causes static assert in type_with_alignment.hpp johnmaddock 1411 Fix BOOST_PARTIAL_SPECIALIZATION_EXPLICT_ARGS johnmaddock 1446 POSIX API doesn't use C locale johnmaddock 1451 error: use of C99 long long integer constant johnmaddock 1626 [type_traits] "bad_alloc is not a member of std" in has_virtual_destructor_test.cpp jsiek 1531 segfault in dynamic_bitset::reference assign operator jsiek 1540 Poisson distribution very slow for large mean (and may also overflow). jsiek 575 Calling subgraph::global_to_local on a root graph jsiek 636 strange compiling problem for transitive_closure jsiek 815 remove_edge core dumps on self-circle jsiek 875 No iterator based constructor for adjacency_matrix jsiek 900 graphml reader namespace handling is broken kaalus 1184 property_tree assignment (operator) bug kaalus 1604 property_tree xml parser doesn't compile with gcc marshall 1252 [pool] severe overhead with unaligned sizes. matias 1406 Understanding the Tables outdated matias 1651 incorrect typedefs in examples nasonov 1220 lexical_cast requires RTTI nasonov 754 boost::any - typeid comparison across shared boundaries nesotto 1629 range/iterator_range.hpp bug no-maintainer 1068 Mersenne twister disables streaming for Visual C++ no-maintainer 1222 lambda::ret<T> should declare result_type. no-maintainer 1270 uniform_smallint doesn't compile with lagged_fibonacci random number generators no-maintainer 1515 [lambda] C4512 warnings from VC8.0 no-maintainer 1544 uniform_01 w/ref template param causes ref to ref error no-maintainer 1546 Method boost::random::uniform_int::operator()(engine_ value) is missing no-maintainer 1572 [lambda] smart pointer const-ness affects its contents no-maintainer 1632 Default Interval rounding policies incomplete no-maintainer 781 Lambda: (_1 + "y")(string("x")) Doesn't Compile no-maintainer 819 uniform_int<> with type's maximum availaible range error pavol_droba 1152 rle_example fails pavol_droba 1385 begin must be boost-qualified pdimov 1106 shared_ptr<T> should not convert to shared_ptr<U> when T* doesn't convert to U* ramey 1285 [serialization] problem when including shared_ptr_132.hpp ramey 1628 Lack of wide character support prevents boost.serialization from linking ramey 1662 boost::serialization for boost::optional - missing include rogeeff 1383 signal.h features not found on Mac OS rogeeff 1542 [test] compiler errors when building with stdcxx library samuel_krempp 859 boost::format ignores a user defined locale shammah 290 perfomance: memory cleanup for pool takes too long shammah 386 boost::pool_allocator breaks with vector of vectors speedsnail 1138 Problems with TSS and static thread library t_schwinger 1100 Building boost.function_types fails cvs rev-1.1_ no chdir command in bash t_schwinger 1602 function_types Jamfile depends on the source tree being in a specific place. t_schwinger 1653 wave executable erroneously required for build of function_types lib turkanis 1523 [iostreams] VC8/VC9 compiler warnings turkanis 1545 [boost/rational.hpp] 'noskipws' is not a member of 'std' turkanis 1579 gzip compressor should model DualUseFilter turkanis 1580 Add static assert to prohibit instantiating a chain with mode dual_use turkanis 1649 Fix definition of JavaScript menu to avoid long chains of functions turkanis 1656 Consider implementing flush() for symmetric filters urzuga 574 [boost::lambda] Compile error with libstdc++ debug mode vladimir_prus 1165 more quoting problems vladimir_prus 1274 Useless error message vladimir_prus 1321 invalid docbook in tool documentation vladimir_prus 1527 [program_options] Second (and subsequent) lines in tabbed text not aligned correctly vladimir_prus 1530 Program options documentation - Overview - Syntactic Information example typo vladimir_prus 1537 no value given in 'mysql_password =' vladimir_prus 1584 cryptic bbv2 error building quickbook vladimir_prus 1587 [program_options] crashes if value part missing in external configuration file vladimir_prus 1588 [program_options] crashes if value part missing in external configuration file vladimir_prus 1645 Invalid unicode support for default_value vladimir_prus 469 multitoken broken vladimir_prus 689 [program_options] Endless loop with long default arguments witt 1046 Boost.Python quickstart instructions mention nonexistent target witt 583 Fixes for build on IBM pSeries for AIX and Linux witt 834 Homepage regression links witt 957 The "Getting Started" page does not mention the stdlib option witt 973 zip_iterator has value_type == reference -- -- Marshall Marshall Clow Qualcomm, Inc. <mailto:mclow@qualcomm.com> The famous British scientist, Lord Kelvin, said: "When you measure what you are speaking about and express it in numbers, you know something about it, but when you cannot (or do not) measure it, when you cannot (or do not) express it in numbers, then your knowledge is of a meagre and unsatisfactory kind."

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Re: [boost] [Boost-users] Ann: Floating Point Utilities Review starts today
by John Maddock 03 Mar '08

03 Mar '08

Johan Råde wrote: > This has been a very valuable review. > I have received a lot of valuable feedback, > many suggestions for how to improve the library, > both interface, implementation and docs. I'd just add a short postscript to this - although the review period is officially over - if there are any late reviews still to come please do still submit them! Regards, John Maddock Review Manager for floating point utilities.

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[1.35][website] Release History; Regression link
by Jonathan Turkanis 03 Mar '08

03 Mar '08

Hi, 1. I just updated boost_1_35_0.qbk; since I don't know the quickbook format, I'd appreciate it if someone would look over it quickly to make sure I haven't broken anything. 2. I've removed an obsolete table of supported compilers from the Iostreams docs; I'd like to replace it with a link to the regression test reports for 1.35, but I don't know where that will be. Thanks, -- Jonathan Turkanis CodeRage http://www.coderage.com

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[Proto] Review
by dan marsden 02 Mar '08

02 Mar '08

Hi Review of Proto Evaluation of the design Excellent. The close collaboration with the Spirit development, and the fact Proto has underpinned xpressive for some time clearly shows in a mature looking library. The library uses MPL, Fusion, the result of protocol and other standard components effectively, making good use of other parts of Boost. One very small implementation question - arg_c doesn't have a corresponding arg, in line with the pattern see in MPL/Fusion for at/at_c etc. Was there a reason for this, if not I'd suggest always having xxx when there is a corresponding xxx_c feature. Evaluation of the documentation Proto's problem domain is naturally quite abstract, and more heavily technical than other Boost libraries. The documentation is of good quality, but I feel there may still be quite a steep learning curve for new users. The examples used are generally quite realistic, but this can mean they're tough to get started with in some cases. Some more trivial examples may help in places. Having said that, I learnt to use Proto from the documentation, so they're certainly sufficient to get going. I found a few specific issues in the docs: * The Transform concept documentation mentions ObjectTransform, but I cannot find any details of that transform in the concepts section * The call<> documentation has a "TODO LINK" left in it. This also brings up a general point, I'd like to see links in code samples etc to the related documentation if possible, it saves backing up and down all the time trying to follow examples. * The documentation for call<> mentions posit<_>. I could not find posit mentioned in the top level documentation - is this a Proto feature, or just part of the example? Again this brings up a general point, it might be good to use namespace qualification to highlight the distinction between library and user code. Usefulness Massive, there are plenty of DSEL's already in Boost, and plenty of others we probably should have. Effort put into review I implemented the (partially complete) port of Phoenix to Proto, using a slightly early version of the library. I've put a few hours study into the latest Proto documentation as I've not been using the library actively recently. Compilers used - gcc 3/4, msvc 7.1/8 Am I knowledgeable in the problem domain? Yes - I've implemented DSELs both with and without Proto, and appreciate the benefits of having the expression template engine in the form of a library. Should Proto be accepted into Boost? Yes Cheers Dan ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/

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Re: [boost] Serialization of Range library's sub_range
by brass goowy 02 Mar '08

02 Mar '08

Brian Wood writes: >Recently, I suggested there should be serialization support wrt >the Range library - >http://lists.boost.org/Archives/boost/2008/01/132294.php. >I'm writing to inform you of my plans in this regard. This input: > >Msgs > (sub_range<list<short> >) @OUT >} > >to the C++ Middleware Writer, http://home.seventy7.com/cgi-bin/samb.cgi, >results in this output: > >#include <boost/range/sub_range.hpp> >#include <list> >#include <Buffer.hh> >using boost::sub_range; > > >struct Msgs >{ >inline >Msgs() {} >inline >~Msgs() {} > >inline >int >Send(Buffer* buf, const sub_range<list<short> >& about1) >{ > unsigned int headCount = 0; > headCount = about1.size(); > if (!buf->Receive(&headCount, sizeof(int))) { > buf->ews_.SetErrorWords(1, __FILE__, __LINE__); > return 0; > } > list<short>::const_iterator rit1 = boost::begin(about1); > list<short>::const_iterator rit2 = boost::end(about1); > for (; rit1 != rit2; ++rit1) { > if (!buf->Receive(&(*rit1), sizeof(short))) { > buf->ews_.SetErrorWords(1, __FILE__, __LINE__); > return 0; > } > } > > if (!buf->SendStoredData()) { > buf->ews_.SetErrorWords(2, __FILE__, __LINE__); > return 0; > } > return 1; >} > >}; > >This functionality isn't available online yet. G-d willing, it >will be available by the middle of next month. Update: the functionality is now available online. Brian Wood Ebenezer Enterprises www.webebenezer.net

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[Review] Proto review starts today, March 1st
by Tom Brinkman 01 Mar '08

01 Mar '08

Proto is the new backend for boost::spirit, boost::xpressive and the re-write of boost::phoenix, this is indeed an important library. It would seem that "Proto" already has the support of all of the top boost developers. 1) I wonder if you could give us a little bit of history, what motivated this library? 2) What were the defincies in previous design of boost::spirit. Why does spirit need a new backend? Learning to use boost:spirit is about a six month learing curve, but well worth it. For me, it was my introduction to functional programming. I'm excited to see what else is possible.

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[thread_safe_signals] new idea for thread-safe automatic connection management
by Frank Mori Hess 29 Feb '08

29 Feb '08

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I came up with another idea for handling automatic connection management in thread_safe_signals (thread-safe version of boost.signals). I've attached some proof-of-concept code. The new code is supposed to enable going back to more of a boost::signals::trackable idea, where you inherit from a "trackable" base class to get automatic connection management. It still requires the trackable object be managed by a shared_ptr, but now the owning shared_ptr would not have to be explicitly passed to the slot for tracking. Also, it should make it possible to track connections to "this" when making connections in a constructor. Instead, the signal (or slot rather) would create a "tracker" object for each trackable object detected by visit_each. The tracker::lock_target() function returns a bool and a shared_ptr which can be in one of three states: bool is false: the trackable object has been destructed and its associated connections should be disconnected. bool is true, and shared_ptr is non-zero: the trackable object is alive and its associated connections should operate normally. The returned shared_ptr can be used to insure the trackable object doesn't destruct while the signal invocation is in progress. bool is true, and shared_ptr is zero: the trackable object is either constructed but not yet owned by a shared_ptr, or it is in the process of being destructed. In either case, the connection would be blocked until one of the other two states is reached. For those who have no idea what I'm talking about, I'll give a little background. The trackable/visit_each scheme of boost.signals was abandoned in thread_safe_signals since it disconnects the connections in the destructor of the trackable class. This isn't thread-safe, since the trackable destructor isn't called until after any derived class' destructors. The replacement idea was to allow shared_ptrs to be passed to slots for tracking. The shared_ptrs are assumed to own (directly or indirectly) any objects whose destruction should cause the slot to automatically disconnect. The slot keeps weak_ptr copies, and disconnects when any of the tracked weak_ptrs expire. The slot's weak_ptrs are all be converted to shared_ptrs whenever the slot is run, to insure the tracked objects don't destruct in the middle of signal invocation. One limitation is an object can't make automatically tracked connections to itself in its constructor, since boost::enable_shared_from_this doesn't work in constructors. - -- Frank -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFHyIM/5vihyNWuA4URApuKAKCAGIT2kMXn8mCBU18/TtySbRF0HACgx/3l Qt6uPigHRD6QREqKW7v/Vjk= =H5Sb -----END PGP SIGNATURE-----

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[thread] best practice to lock multiple mutexes
by Kowalke Oliver (QD IT PA AS) 29 Feb '08

29 Feb '08

Hi, what's the best practice in following scenario: m threads and n resources (each resource is protected by a mutex) thread x needs read/write access to resources (...i,j,k,..) threads y,z,... do access another subset of resources at the same time inorder to protected deadlocks I would do following in the code of the different threads (code executed by the threads are different): ... try_lock: // label unique_lock< mutex > lk1( mtx1, try_to_lock_t); unique_lock< mutex > lk4( mtx2, try_to_lock_t); unique_lock< mutex > lk7( mtx3, try_to_lock_t); if ( ! ( lk1 && lk2 && lk3) ) goto try_lock; // all mutexes are locked // now modify safely resource 1,2,3 ... Maybe you have a better pattern do solve this problem? best regards, Oliver

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