March 2008 - Boost - lists.boost.org

Trac open bugs - by assignee
by Marshall Clow 31 Mar '08

31 Mar '08

[ 245 open bugs today, 238 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 24 djowel 22 az_sw_dude 17 grafik 15 vladimir_prus 13 dgregor 13 dave 12 doug_gregor 12 bemandawes 11 no-maintainer 11 agurtovoy 8 anthonyw 7 turkanis 7 jsiek 6 ramey 6 matias 5 witt 5 igaztanaga 4 johnmaddock 4 ebf 3 rogeeff 3 nesotto 3 nasonov 3 kaalus 3 danielw 3 danieljames 2 shammah 2 samuel_krempp 2 pdimov 2 pavol_droba 2 marshall 2 jmaurer 2 hkaiser 2 aaron_windsor 2 None 1 urzuga 1 t_schwinger 1 speedsnail 1 garcia 1 fcacciola 1 dlwalker 1 chris_kohlhoff None 1644 Boost.Test missing documentation file BOOST_CHECK_CLOSE_FRACTION.html None 1736 Headers containing non ASCII characters cause MS VC to issue warning 4819 in some locales 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 1657 Bug in boost::threads sample anthonyw 1713 no definitions for copy ctor and assignment operator for basic_condition_variable 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 1674 date_time::date_formatting.hpp: incorrectly formats year using global locale az_sw_dude 1695 add correct namespace to class to fix compilation bug az_sw_dude 1726 boost/date_time/posix_time/time_formatters.hpp incorrectly formats fractional seconds using global locale 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 1682 path_traits needs imbue() bemandawes 1701 boost::filesystem::remove_all - segmentation fault with wpath on Linux bemandawes 1711 Boost Serialization export facility broken on gcc 4.1_ 4.2 bemandawes 752 directory_iterator doesn't work with catch chris_kohlhoff 1703 [asio] Compiler warnings on VC8/9 + warning level 4 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 danieljames 1705 [boostbook] Spaces in reference file names for types like 'long long' 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 1697 [utility][noncopyable] ADL barrier broken by msvc-9.0 dave 865 Use of C++0x keyword as identifier dave 910 gcc strict-aliasing problems with python dgregor 1009 Improper overflow handling in shortest paths algorithms 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 1395 Write Tests for Python Bindings dgregor 1630 gcc-4.3: adjacency_list.hpp includes deprecated header dgregor 1680 long long and wchar_t support in MPI 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) djowel 1722 [TR1/Fusion] Conflict between TR1 and Fusion headers 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 fcacciola 1666 Visualizer for boost::optional 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 1730 No debug libs on Windows by default grafik 1733 Website layout overlays on IE7 grafik 1735 [website] Wrong HTML on main documentation page. 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 1670 wave almost unusably slow on real-world input 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 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 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 kaalus 1678 Boost.property_tree::read_xml does not parse UNICODE file with BOMs marshall 1252 [pool] severe overhead with unaligned sizes. marshall 1493 SVN files making it through to install matias 1406 Understanding the Tables outdated matias 1651 incorrect typedefs in examples matias 1676 Dead links on Boost.Test example documentation. matias 1707 small typos in Boost.serialization documentation matias 1727 Sample code in documentation does not compile_ has namespace errors. matias 1731 Website 'bugs' nasonov 1220 lexical_cast requires RTTI nasonov 1704 [any] 4512 warning from VC8/9 on warning level 4 nasonov 754 boost::any - typeid comparison across shared boundaries nesotto 1629 range/iterator_range.hpp bug nesotto 1675 [range] VC8 - compiler warnings when including range/array headers nesotto 1694 NDEBUG vs. BOOST_ASSERT in iterator_range.hpp 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 1691 [Random] Brokem MSVC workaround 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* pdimov 1719 [addressof] Can't obtain the address of an instance of an anonymous struct ramey 1285 [serialization] problem when including shared_ptr_132.hpp ramey 1708 Can't serialize class with private destructor ramey 1715 gcc-4.3 doesn't compile polymorphic_(i)(o)archive.hpp ramey 1721 Serialization examples don't compile in trunk for G++ 4.1 ramey 1725 Boost Serialization examples do not compile on RC3 ramey 1734 BOOST_STATIC_WARNING can't be passed a dependent expression rogeeff 1383 signal.h features not found on Mac OS rogeeff 1542 [test] compiler errors when building with stdcxx library rogeeff 1723 No subprocess can be started in init_unit_test_suite samuel_krempp 1699 Compile warning about initialization order. 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 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 turkanis 1671 type mismatch of buffer size parameter causes overload resolution to fail urzuga 574 [boost::lambda] Compile error with libstdc++ debug mode vladimir_prus 1132 program_options documentation error. 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 1679 added 4-way universal binary support from mac osx (ppc_ ppc64_ i386_ x86_64) vladimir_prus 469 multitoken broken vladimir_prus 689 [program_options] Endless loop with long default arguments vladimir_prus 850 program_options strips off escaped quotes in some situations 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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GSoC Ideas
by Cristianno Martins 31 Mar '08

31 Mar '08

Hello everybody, I'm Cristianno Martins, I'm starting master degree at State University of Campinas (Brazil), and I'm very interested in participate of a Google Summer of Code Project. This is the first time that I'm intending to develop some open source code. There are many projects listed in GSoC home page, and I almost read all of them, choosing two or three to write a propose. So, I really liked two ideas between the boost potential projects: - safe integer -> basically, a creation of a template class to safely access values in the memory; - parallelizing Boost.Math -> using OpenMP to enable the source of Boost.Math to run in multicore systems. I actually believe that I can do anyone of them, and I wanna propose a project to each one. I only needed to know if anything is being done about some of those. I also wanna know if someone have ideas to be done in these projects and aren't listed at the Boost projects list. Best, -- Cristianno Martins Mastering in Computer Science State University of Campinas cristianno.martins(a)students.ic.unicamp.br skype:cristiannomartins g-Talk: cristiannomartins msn: cristiannomartins(a)hotmail.com

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Re: [boost] [1.35] compile with vc8 the co-existence of vc8 &
by Tan, Tom (Shanghai) 31 Mar '08

31 Mar '08

Tan, Tom (Shanghai) wrote: > Hello, > > I have both VC8 and VC 9 installed on my machine. It's quite smooth to > build with vc9. However even if I started from VC8 command line prompt > and it seems to build with vc9 still, even if I use this command: " bjam > -toolset=msvc-8.0 install". > Is the above an accurate command? The "-toolset=msvc-8.0" has either one > dash too much or one dash too few from any working one. > - Volodya I did use "bjam --toolset=msvc-8.0 install" actually, sorry for the typo. However, it seems OK now after I changed to "bjam --toolset=msvc-8.0 --build-type=complete install"

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[fusion] Small issues in documentation
by Sergei Politov 31 Mar '08

31 Mar '08

Hi, I've found the following small issues in Boost.Fusion documentation. 1) http://www.boost.org/doc/libs/1_35_0/libs/fusion/doc/html/fusion/ organization.html - I'm pretty sure that rect should not be blank. 2) http://www.boost.org/doc/libs/1_35_0/libs/fusion/doc/html/fusion/support/ is_view.html#fusion.support.is_view.example - line "using boost::mpl::_" does not contain trailing ;. 3) http://www.boost.org/doc/libs/1_35_0/libs/fusion/doc/html/fusion/support/ pair.html#fusion.support.pair.expression_semantics - invalid table. Best Regards, Sergei

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[1.35] compile with vc8 the co-existence of vc8 & vc9
by Tan, Tom (Shanghai) 31 Mar '08

31 Mar '08

Hello, I have both VC8 and VC 9 installed on my machine. It's quite smooth to build with vc9. However even if I started from VC8 command line prompt and it seems to build with vc9 still, even if I use this command: " bjam -toolset=msvc-8.0 install". Is there any way to force to go with vc8?I need to build both version of lib. Thanks, Tom

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Need help with REGEX expression ( boost::regex_search )
by Danny Gilbert 31 Mar '08

31 Mar '08

Hi ! I work with Visual Studio 2003, C++. I am reading data from a UNICODE file in a std::wstring. (It works fine) I want to find with boost::regex_search a pattern like the following: @@FOREACH(item in list) data @@END I want 3 substrings (submatch) like the following: 1- item 2- list 3- data We can have line feed, carriage return, space, etc. between ( and item, between ) and the data, and between data and @@END. So the following must work: @@FOREACH( item in list ) data @@END I DID MANY THINGS (TRY AND ERROR) AND I CAN FIND the first submatch item and the second submatch list. The third submatch never works. It don't see the @@END command (instruction) and get all the remaining stuff of the string. I used Regex Coach software and Rad Regex Designer but with theses softwares, my REGEX expression works. What is the correct REGEX expression with BOOST ???? Thank you ! :-( -- View this message in context: http://www.nabble.com/Need-help-with-REGEX-expression-%28-boost%3A%3Aregex_… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Runtime dynamic dispatcher [was: Overload V2]
by Marco Costalba 31 Mar '08

31 Mar '08

While I was reading the very nice Dynamic Dispatcher Library by Dean Michael Berris (dispatcher-0.2.zip in Vault) I realized that it is possible to magically ;-) get a runtime dynamic dispatcher out of the overload library simply using a container to store overloads ! More, the dispatcher you get is multi-signature (heterogeneous function types), instead of homogeneous function type as is the Dean's one. The key enabler is that class overload has value semantic. Of course with the Dean's one you get more, in particularly you get: - Strategized Index Validation - Strategized Routing - Scheduled/Sequenced Invocation But if you are not interested in this additional features you can give overload a try. I have updated the docs and the examples in Vault (overload_26_3_2008.zip) to reflect this new "discovery" ;-) Dean, I' didn't realized this use of overload as a dispatcher until reading your code, are you still interested in a multi-signature dispatcher? Thanks Marco

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Egg Review starts today March 31st
by dan marsden 31 Mar '08

31 Mar '08

The review of the Egg library by Shunsuke Sogame starts today.The library is concerned with the implementation and adaptation of function objects. As function objects are everywhere in Boost and C++, I hope to see plenty of discussion and votes during the review. Introduction: It is not so easy to define Function Objects especially if you want to support Boost.ResultOf and Boost.Lambda. Therefore, as Boost provides iterator_facade and iterator adaptors, Egg provides function_facade and function adaptors. Egg provides the following features: * Workaround for the Forwarding Problem http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2002/n1385.htm * Helpers to build Function Objects: * egg::function and egg::function_facade provides the way to build Function Objects which supports Boost.ResultOf and Lambda. * Function Objects Adaptors(in other words, higher-order functions): * egg::curryN supports the currying. * egg::pipable emulates extension methods(C#). * egg::fuse/unfuse emulates variadic functions. * egg::nestN represents nested lambda expressions. * etc... The documentation is on line: http://p-stade.sourceforge.net/boost/libs/egg/ The zipped source code is in Vault/FunctionObjects: http://tinyurl.com/34lgda Tested under: Boost Development Trunk and Boost Version1.34.1. --------------------------------------------------- Please always state in your review, whether you think the library should be accepted as a Boost library! Additionally please consider giving feedback on the following general topics: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? Thanks Dan Marsden Review Manager ___________________________________________________________ Yahoo! For Good helps you make a difference http://uk.promotions.yahoo.com/forgood/

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[boost-1.35] supported compilers - suggestion
by Kowalke Oliver (QD IT PA AS) 31 Mar '08

31 Mar '08

Hello, on the boost-page I've read that gcc is only supported on Linux and Solaris. I would suggest to add to the note that gcc is also supported (and can compile boost) on HP/UX. best regards, Oliver

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[proto] design of expr<>
by Markus Werle 31 Mar '08

31 Mar '08

Hi! I want to discuss the internal data structure expr<>: I like the way expr<> is built regarding to the first and second template argument: It is well thought and done to have the expression tag as first argument and some fusion-compatible typelist as its second argument containing the operands. OTOH the third template argument contains redundant information: The docs say: "Proto expression nodes are valid Fusion random-access sequences of their children nodes." So the information about the number of arguments is accessible via some size<T>::type metafunction e.g. depending on result_of::distance<result_of::begin<S>::type result_of::end<S>::type>::type? In my unfinished attempts to write a paper about ET library design (now obsolote, thanks to Eric) I have a statement that any expression representation taking more than 2 template arguments is wrong. Eric, since you always have a good reason for your design: Could you please elaborate on this? Also I ask myself whether there was a good reason not to follow mpl and use types to represent numbers. I'd prefer at least some parallism to mpl here: size_t<c>? Markus

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