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Logging library review.
by Jurko Gospodnetić 19 Feb '08

19 Feb '08

Hi. Unfortunately I did not get enough free time to play around with this library as much as I would have liked. But here's what I have so far. I'll skip topic I feel were already covered sufficiently during this review and/or John already accepted to correct/change them. ---------------------------------------- * What is your evaluation of the design? ---------------------------------------- Natural. :-) Logging is one of those topics in which everything has been done before, things seem to be added one by one as needed to this one... There are some things I find no simple way to implement: * Filtering based on logged data. E.g. imagine logging airplane takeoffs and landings and wanting to log only landings for airplanes coming in from Frankfurt. * Filtering log messages so that they end up getting written to only some destinations. E.g. specifying at run-time that you want information about those same airplanes from Frankfurt logged to the output screen while all output, including this one, gets logged to the main network logging server. ------------------------------------------------ * What is your evaluation of the implementation? ------------------------------------------------ Have not delved much into the implementation details so here are just a few comments. Should spell out variable/function/class names without using short forms like 'idx' for 'index'. OK, maybe the code needing to be written can not get smaller... but when I look at the examples and the code I wrote I just get a gut feeling that 'something smells' there. Just seems like there is room for improvement. Exactly what it is... only usage will tell... :-) Should be reviewed carefully to make sure it does not to allow throwing exceptions from destructors. As I mentioned in another post (and never got John's answer to that one) - why not make logger initialization simpler by doing the following: * Remove the mark_as_initialized() function. * Allow loggers to be enabled or disabled. * When disabled, allow loggers to cache or ignore their log messages (subject to regular filtering). * Create loggers as active by default. * Allow the user to create loggers inactive and activate them later when appropriate. This way the most common use case when you do not need log caching would be simple and intuitive... and when someone needs caching - they will have no objection to having to enable it - and will even be glad that they have that functionality available. :-) This effectively solves the problem with users not being aware they need to call mark_as_initialized(). ----------------------------------------------- * What is your evaluation of the documentation? ----------------------------------------------- Good enough for getting an overview of the library. Too informal. All the information I needed was in there, but it was sometimes a bit hard to track down. I read the documentation first and then it often happened that I knew I saw something in there but had not idea where to look for it again. Looking at the main index did not help narrow down the choices. Long live grep! :-) Should explicitly document possible exception throws. Comparison between different logging solutions would be nice. Nothing about the documentation is a show-stopper. It should become much better 'naturally' with a few people reading through it and giving feed-back. Oh yeah... just another 'nitpicking detail'... the new changes page (http://torjo.com/log2/doc/v3/html/page_changelog.html) has a messed up header for release v0.22.7. :-) --------------------------------------------------------------------- * What is your evaluation of the potential usefulness of the library? --------------------------------------------------------------------- Enormous. I believe that a logging library that managed to get into boost would be instantly grabbed by a large and high quality user base. Existing solutions are mostly hand-crafted and no packaged logging library I ever tried had all the functionality I needed (OK, most of them had it on paper, but caused crashes and such when you attempted to use it. :-)) The main problem with existing libraries I tried is that they left me with a feeling that 'no-one is developing them'. Most of them seem dead and others give only responses like 'that does not work at the moment, no one is working on it but if you need it - you can implement it yourself'. IMHO, they just did not have a large enough quality user base and development effort behind them to push them forward. ---------------------------------------------------------------------- * Did you try to use the library? With what compiler? Did you have any problems? ---------------------------------------------------------------------- MSVC 7.1. and there were no problems that I could blame the library for except perhaps that it just seemed easy to make a mistake and have something 'not work'. But every such mistake was easy enough to locate and correct. As before - the library will get better at this as it matures. ---------------------------------------------------------------------- * How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? ---------------------------------------------------------------------- Read the documentation, tried out several simple test logging scenarios and played out others on paper comparing them to the library's documentation. ------------------------------------------------- * Are you knowledgeable about the problem domain? ------------------------------------------------- Somewhat. Implemented several simple logging solutions. Thought about the subject a lot. Involved in maintaining several active applications where logging is of tremendous use. ---------------------------------------------------------------- * What more do you wish to see changed/added/implemented in this library? How would you like to be able to use it? ---------------------------------------------------------------- I would like it to provide simple non-throwing logging support so logging can be made safe in destructors without having to fear my program crashing because of a failed log. I would like to see additional effort to make it difficult for logging messages to be lost accidentally, e.g. using preallocated storage for log messages, leaving log messages queued in the preallocated storage in case their output fails and retrying the output at a bit later time, together with a message that the original output failed. At the very least, I would like a message logged stating that some log messages got lost if this happens (possibly with the exact number of lost messages). The v1 functionality with specifying multiple loggers as a group using the hierarchical string syntax should be restored. I have used hand-crafted logging code supporting it before and it is a great feature allowing you to specify what to log and where to log it to at run-time and with different scope. ----------------------------------------------------------------- * Do you think the library should be accepted as a Boost library? ----------------------------------------------------------------- My vote would be 'Yes, accept it'. It seems good enough for me. This library's has one thing special about it and it seems both a curse and a blessing. It is the fact that the library, once accepted, is likely to get a huge user base. With such a user base it should be easy for it to evolve, but it will also create more and more pressure to provide a stable interface and backward compatibility. That and the fear of John stopping developing the library before it finds a new maintainer are pretty much the only reasons why I considered voting 'No'. Logging is such a 'wide' topic, with many interested parties, every one of them having its own vision of what logging is supposed to be. As a result - I believe we have a chicken & egg problem here. :-) It does not seem likely it will be possible to satisfy everyone just by 'designing' the library but on the other hand it needs to evolve by receiving actual user feedback. The current solution seems 'good enough' for me, and IMHO for any logging library there will always be someone who will think it is not 'good enough'. Keeping it rapidly evolving seems like the only way to go, and I'd rather use and contribute to a Boost library than other solutions I've tried so far. One thing did bother me during this review. I would like to see different logging library authors working more closely and possibly on a single logging library. Maybe its just me, but I did not like the tension/antagonism I sensed between them. :-( That said, John seems highly enthusiastic about completing this library and I do have faith that he will update the library with respect to all the suggestions collected during this review. Kudos to him on the work done so far, great enthusiasm and not buckling beneath all pressure caused by a Boost review of such complex topic as logging. Best regards, Jurko Gospodnetić

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[Boost.Test] should we add operator<<() for standard containers etc
by Thorsten Ottosen 19 Feb '08

19 Feb '08

Hi Gennadiy, I've just implemented some comparison operators for Boost.Assign's list_of(): typedef std::vector<int> Seq; BOOST_CHECK_EQUAL( ba::list_of(0)(1)(2), (Seq)ba::list_of(0)(1)(2) ); BOOST_CHECK_NE( ba::list_of(0)(1)(2), (Seq)ba::list_of(-1)(1)(2) ); BOOST_CHECK_LT( ba::list_of(0)(1)(2), (Seq)ba::list_of(0)(1)(3) ); BOOST_CHECK_LE( ba::list_of(0)(1)(2), (Seq)ba::list_of(0)(1)(2) ); BOOST_CHECK_GT( ba::list_of(0)(1)(3), (Seq)ba::list_of(0)(1)(2) ); BOOST_CHECK_GE( ba::list_of(0)(1)(2), (Seq)ba::list_of(0)(1)(2) ); This works, but I need to specify how to stream the other type of argument, in this case an std::vector<int> object: namespace std { template< class T, class Elem, class Traits > inline std::basic_ostream<Elem,Traits>& operator<<( std::basic_ostream<Elem, Traits>& Os, const std::vector<T>& r ) { return Os << ::boost::make_iterator_range( r.begin(), r.end() ); } } Since there are so many ranges out there, mabe it would be better to add the following. We already have BOOST_CHECK_EQUAL_COLLECTIONS(x,y,z,w) (but where is BOOST_CHECK_NE_COLLECTIONS etc?) then why not add BOOST_CHECK_EQUAL_RANGE( Rng1, Rng2 ) // implement by calling make_iterator_range() on the two arguments Also, I would like to see BOOST_CHECK_NE_RANGE( Rng1, Rng2 ) BOOST_CHECK_GT_RANGE( Rng1, Rng2 ) BOOST_CHECK_GE_RANGE( Rng1, Rng2 ) BOOST_CHECK_LT_RANGE( Rng1, Rng2 ) BOOST_CHECK_LE_RANGE( Rng1, Rng2 ) Any thoughts? -Thorsten

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Logging library review is finished. Really.
by Gennadiy Rozental 18 Feb '08

18 Feb '08

Phew! That's was quite interresting discussion. Thanks again to everyone participated. Due to large number of huge reviews and some number of enourmous, I'll need some time to mull over it to make a decision. Gennadiy Rozental - Review Manager -

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Boost Exception update
by Emil Dotchevski 18 Feb '08

18 Feb '08

I would like to once again thank Tobias Schwinger, the review manager for Boost Exception, and to everyone who participated in the review process. Current documentation and source code can be downloaded from: http://www.revergestudios.com/boost-exception/boost-exception.html I have updated Boost Exception with the following requests and suggestions from the review: - added support for exception cloning - simplified the syntax for adding data to exceptions - added support for combining data into boost::tuple instead of the requested support for grouping of error_info objects - modified boost::throw_exception to ensure that all exceptions emitted from it support cloning and adding of arbitrary data types. The last change introduces dependency of throw_exception.hpp on a couple of boost components: intrusive_ptr and detail/atomic_count. Also, I know that my changes to boost::throw_exception are not compatible with older compilers such as VC6, or BCC5, or GCC295, etc. It might be possible to work around this, but I'm wondering if it's worth the effort. I think that it is reasonable to simply disable Boost Exception for these compilers (or else my throw_exception.hpp change would break things like shared_ptr which do work with these old compilers.) Let's discuss this issue before I submit the Boost Exception source code to SVN. Emil Dotchevski http://www.revergestudios.com/reblog/index.php?n=ReCode

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Trac open bugs - by assignee
by Marshall Clow 18 Feb '08

18 Feb '08

[ 212 open bugs today, 211 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 13 grafik 12 doug_gregor 12 dgregor 12 dave 11 vladimir_prus 11 agurtovoy 10 no-maintainer 9 bemandawes 7 jsiek 7 anthonyw 6 johnmaddock 5 witt 5 turkanis 5 igaztanaga 4 pdimov 3 nasonov 3 ebf 3 danielw 3 danieljames 2 t_schwinger 2 shammah 2 rogeeff 2 ramey 2 pavol_droba 2 kaalus 2 jmaurer 2 hkaiser 2 aaron_windsor 1 urzuga 1 speedsnail 1 samuel_krempp 1 nesotto 1 matias 1 marshall 1 hljin 1 garcia 1 eric_niebler 1 dlwalker 1 None None 1493 SVN files making it through to install 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 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 danieljames 1573 Broken URL in copyright boiler-plate 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 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 993 Variant should use least common multiple of alignments_ rather than maximum eric_niebler 1631 [accumulators] compiler warnings with VC9 + warning level 4 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 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 nasonov 1220 lexical_cast requires RTTI nasonov 1637 Minor typo in lexical_cast.hpp 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* pdimov 1444 scoped_ptr::operator== should be equivalent to a.get()==b.get()_ but is currently !!a==!!b pdimov 1590 shared_ptr documentation inconsistency pdimov 779 gcc-4.2 atomicity.h location ramey 1285 [serialization] problem when including shared_ptr_132.hpp ramey 1628 Lack of wide character support prevents boost.serialization from linking 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. 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 1624 consider making chain/filtering_streambuf/filtering_stream closable 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 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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Question regarding check-in
by Robert Ramey 18 Feb '08

18 Feb '08

I've made quite a few changes on a branch "next_serialization_library". Last November(or October?) I asked about merging them into the trunk. It was suggested that that might not be the best time as release of 1.35 was expected "soon". Well, not its almost march. Would this be a good time to merge these changes in? I test on my own machine with MSVC 7.1, MSVC 8.0 and gcc 3.4?. But I would be curious to know how it works with other compilers. When would be a good time to merge in these changes? Robert Ramey

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Logging library review
by Vadim 18 Feb '08

18 Feb '08

> * What is your evaluation of the design? Good analysis of the target domain, clean separation of concerns. However the flexibility of this is throwing too much burden on the user and has made the barrier to entry too high. IMO, simple usages can be made simpler without sacrificing much of extendability. > * What is your evaluation of the implementation? Didn't look much into it > * What is your evaluation of the documentation? Too complex and can turn away many potential users. Too many times terms are introduced without being clearly explained. It lacks a natural flow and appears chunky. Maybe the choice of doxygen to partly to blame since it encourages such style. Maybe it is great for "advanced" section, but introduction could benefit from old-fashioned sequential writing. > * What is your evaluation of the potential usefulness of the library? Significant. Every project I encountered needed a logging facility, and this library is open enough to actually cover significant portion of uses with some extending. > * Did you try to use the library? With what compiler? Did you have any > problems? In a simple test project with VC 7.1, trying to re-create functionality provided by v1 of the logging library, namely the ability to create a hierarchy of loggers, such as "system.network.tcpip" or "system.storage.db", and configure different outputs dynamically, based on modules and levels, at run time. * Single threaded configuration not supported, fails with somewhat cryptic message in cache_before_init:43 * a list of dependencies on other boost libs in the docs could be helpful * could not figure out which tradeoffs that scenario::usage is supposed to resolve. * decoupling the tags example from scenario::usage turned out not trivial. * hit some sort of appender vs prepender conflict while playing with combining named_spacer with tags formatter. * didn't like the DEFINE_LOG_XXX /DECLARE_LOG_XXX macros and would prefer to have the code behind them visible. > * How much effort did you put into your evaluation? A glance? A quick reading? > In-depth study? About 6 hours overall. Within that time frame, I have been unable to replicate v1 functionality, but it appears that the design does not precludes it. However, I'd strongly prefer that functionality to be available out of the box. > * Are you knowledgeable about the problem domain? Reasonably so: I've evaluated several logging libraries, developed and deployed my own library in past. Also had experience integrating boost::logging v1 library into ~100KLOC project. > And finally, every review should answer this question: > > * Do you think the library should be accepted as a Boost library? > Be sure to say this explicitly so that your other comments > don't obscure your overall opinion. Yes, with some improvements to documentation and ease-of-use, I believe it will make a valuable addition to boost. While I agree with previous reviewers about quality requirements for boost logging library, my opinion is that "yes, with improvements" vote will better serve that purpose, in encouraging John not to go for another 2-year redesign cycle. Best regards, Vadim

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Logging library review extension is at it final day
by Gennadiy Rozental 18 Feb '08

18 Feb '08

Welcome everyone to the last day of the official review of proposed Logging library. I would like to encourage anyone interested in this very important and complex problem domain to invest some time and give this submission a shot. Whether you are novice developer looking to use logging facility or experienced designer developed it once or twice already, your opinion is valuable. Here is the links to the online docs http://torjo.com/log2/doc/html and package for download http://torjo.com/code/log2.zip. This is the point when you shouldn't leave it for later. If you care to be heard, we need to hear your voice now. Gennadiy Rozental - Review Manager -

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Logging Library Review
by Christian Holmquist 18 Feb '08

18 Feb '08

Logging library review This is my first boost review, so could be it lacks a lot of things.. * What is your evaluation of the design? IIUC, the library provides a flexible solution to compile-time definitions of different loggers. IMO, this is rarerly the case. What should be configured at compile time are the tags (or simplier, the message type). All the rest, destinations, formats, interval, caching, etc is not the responsibility of the programmer defining the log, this is the responsibility of some other programmer using the first programmers library, or the customer using the first programmers application. Destinations will be added at runtime (such when opening a telnet console, typing 'enable-log debug' or similar), configured at runtime, removed at runtime. These scenarious are not even discussed, which make me doubt the library. It seems that formatters are attached to the top level writer object, is this the only way? The formatted message may need to vary for different destinations. I would typically have the file logs to include more data (tags, if you will) then the console destination, making it easier to read the console for human eyes(no timestamps, codelines, etc). If there are some data missing while I look at the console, I would at runtime change the formatter to include some more. * What is your evaluation of the implementation? Didn't look much, but I'm strongly against configuration macros and small utility macros for things that could be written without them. * What is your evaluation of the documentation? I share the same opinion about the documentation as others have already said. It's confusing to read, and sometimes I think that the library is more useful than the documentation makes it, but I'm not convinced. * What is your evaluation of the potential usefulness of the library? A logging library is indeed very useful, I am not sure about this one though. I don't agree with other reviewers that boost must have a logging library for its own sake. With spirit, for instance, I can enable logging to std::cout perfectly for debugging my grammar, no need for very large frameworks for that. Talking about which, how would that work with the proposed library? * Did you try to use the library? With what compiler? Did you have any problems? Tried some of the samples with vc8, no problems. * How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? Read the documentation a couple of hours and looked at the examples. * Are you knowledgeable about the problem domain? Yes. I've written and maintained a log library that's been running for many years. * Do you think the library should be accepted as a Boost library? No, sorry. Could be that the flexibility and customization I am looking for is in there already, but the documentation is written with other scenarios in mind than I have. It should be addressed how the logging library will be configured when used in: * an external header only library (ex, spirit). * an external compiled static library (ex, serialization.lib). * an external compiled dynamic library (ex, serialization.dll/so). * an application, that is shipped/sold to third party. * an application, where destinations are added/removed at runtime from multiple threads. To me a logging library plays a very important role in large software projects since it becomes a part of the interface of an application, note merely being a building block for the programmers behind the application (like std::vector<> for instance =). What is goal of the library? Regards, Christian

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Logging Library Review
by Jamie Allsop 18 Feb '08

18 Feb '08

Before I give my review I want to point out that I have been using John's first logging library (with several key modifications) in production for a couple of years now. On the whole it has been quite a good library. Apart from allowing definition of logs in header files only I did not have too much difficulty massaging it to fit my needs. My approach to looking at this newer version of the library was to see if I could use it in a way that is similar to how I have used the first version. In addition I also wanted to see if it was possible to move past limitations I encountered in the first revision. Therefore with this review I'll point out what I tried to do with the library to put into context my later comments on it. Now for me I see logging as a very important library. There are plenty of options out there and many of us will have written our own at some point or other. With that in mind I feel that a logging library in boost is simply not about providing a library that allows logging. It is about tackling and solving the most critical aspects that any logging library will address, and providing a good interface on which to build more complex libraries related to logging. If a logging library is to be added to boost, then 'good enough' is simply not good enough. If I wanted 'good enough' I can write my own or choose from many of the libraries out there (including this one). So what are the minimum requirements? Well certainly there are a few and there is a good attempt at capturing them here <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?Boost.Logging> For me though I wanted to be able to a couple of things and my efforts at using the library are focused on these. Essentially I wanted to be able to cheaply define logs in different scopes in what I would term library code. Therefore users of the library must be able to use the libraries without logging enabled and pay no cost. The fact that I have logging statements within my code should be transparent to them. At the log site I want to be able to write something like this (or even better, don't use a macro): BOOST_LOG(info) << "Some message" << std::endl; or perhaps BOOST_LOG(info,some_log_name) << "Some message" << std::endl; A number would also be sufficient instead of a level. This would be my default usage. Now I would like the client of the library to be able to enable and disable my logs in a simple fashion, for example using something like, boost::logging::enable_logs( "libraryx.*" ); Finally I'd like the client to specify what actually gets logged and in what format, things like, time level thread file line function That iwa my basic requirement. I tried to achieve this with this library. Now it is not actually possible to do that with this library in a convenient way because this version, unlike the last, does not support the notion of named logs in hierarchies. Having said that I had a go anyway to see how far I could get. I should also point out that I wanted as painless a way as possible of using logging (please see past my macro examples... that's what I started with in this library so it is hard move away from that) --- for adding log messages --- 1. #include <boost/logging/logging.hpp> 2. BOOST_DEFINE_LOG_IN_CURRENT_SCOPE or BOOST_DEFINE_NAMED_LOG_IN_CURRENT_SCOPE(some_name) 3. BOOST_LOG(level) << "message" << std::endl; --- for outputting logged messages --- 1. define a preferred format or simply take a good default 2. say where you want to log to 3. enable the logs you want --- I ended up writing a small file, <boost/logging/default.hpp> which basically provided wrapper macros for the ones that John has in his library. Here is what I put in it. ----------- #ifndef INCLUDED__boost__logging__default_HPP #define INCLUDED__boost__logging__default_HPP #include <boost/logging/format_fwd.hpp> #include <boost/logging/tag/high_precision_time.hpp> #include <boost/logging/format/formatter/tags.hpp> #include <boost/logging/format/formatter/high_precision_time.hpp> #include <boost/logging/format/formatter/named_spacer.hpp> namespace { typedef boost::logging::tag::holder < boost::logging::optimize::cache_string_one_str<>, boost::logging::tag::high_precision_utc_time, boost::logging::tag::level, boost::logging::tag::file_line, boost::logging::tag::function, boost::logging::tag::thread_id > default_tag_holder_string_t; } BOOST_LOG_FORMAT_MSG( default_tag_holder_string_t ) #define BOOST_LOG_DEFINE_LOGGER(name)\ BOOST_DEFINE_LOG(name,boost::logging::logger_format_write<>) #define BOOST_LOG_DEFINE_FILTER(name)\ BOOST_DEFINE_LOG_FILTER(name,boost::logging::level::holder) #define BOOST_LOG_ADD_DEFAULT_FORMAT_TO_SCOPE(logger_scope)\ logger_scope::logger()->writer().add_formatter\ ( boost::logging::formatter::named_spacer\ ("%time% %level% %file_line% {%function%} [%thread_id%] ")\ .add( "time",\ boost::logging::formatter::\ high_precision_utc_time\ ( "$yyyy-$MM-$dd $hh:$mm:$ss.$micro" ) )\ .add( "level",\ boost::logging::formatter::tag::level() )\ .add( "file_line",\ boost::logging::formatter::tag::file_line() )\ .add( "function",\ boost::logging::formatter::tag::function() )\ .add( "thread_id",\ boost::logging::formatter::thread_id() ) );\ logger_scope::logger()->writer().add_formatter\ ( boost::logging::formatter::append_newline_if_needed() ); #define BOOST_LOG_ADD_FILE_DESTINATION_TO_SCOPE(logger_scope,name)\ logger_scope::logger()->writer().add_destination\ ( boost::logging::destination::file( name ) );\ logger_scope::logger()->mark_as_initialized(); #define BOOST_LOG_ADD_DESTINATION_TO_SCOPE(logger_scope,type) \ logger_scope::logger()->writer().add_destination\ ( boost::logging::destination::type() );\ logger_scope::logger()->mark_as_initialized(); #define BOOST_LOG_DEFINE_LOG_IN_CURRENT_SCOPE\ static BOOST_LOG_DEFINE_LOGGER(logger)\ static BOOST_LOG_DEFINE_FILTER(filter) #define BOOST_LOG(the_level)\ BOOST_LOG_USE_LOG_IF_LEVEL\ ( logger(), filter(), the_level ) \ .set_tag( BOOST_LOG_TAG_LEVEL(the_level) ) \ .set_tag(BOOST_LOG_TAG_FILELINE) \ .set_tag(BOOST_LOG_TAG_FUNCTION) #endif // INCLUDED__boost__logging__default_HPP ----------- Ok, that's pretty hideous and I really don't like using macros, however it did allow me to add reasonable default logging. For example I can now write, --- #include <boost/logging/default.hpp> struct some_class { BOOST_LOG_DEFINE_LOG_IN_CURRENT_SCOPE inline void some_method() { BOOST_LOG(info) << "message" << std::endl; } }; --- To use the log I now write in some initialisation method elsewhere, --- void another_class:: initialise_logging() { boost::filesystem::path ExecutablePath( boost::filesystem::initial_path() ); boost::filesystem::path LogPath( ExecutablePath / "logfile.log" ); std::string LogFile( LogPath.string() ); BOOST_LOG_ADD_DEFAULT_FORMAT_TO_SCOPE (some_class) BOOST_LOG_ADD_FILE_DESTINATION_TO_SCOPE(some_class, LogFile); } --- For every log I want to use I have to add more entries, making this function very long for any remotely complex application. I am not advocating this. I'm merely pointing out that for the usage I was looking for, this library made it hard. In fact I wasn't able to use it as I had hoped and the only way I could get somewhat close was to write yet more macros. I believe this example is important because I see this as probably the most basic use of the logging library beyond simply writing to file directly (or std::cout or anywhere else for that matter). What I presented above is not acceptable, but I do believe the author has the ability to address these issues. In essence I think the above example should be very easy to write, with as few lines as possible and *only* use macros where absolutely necessary. It should be acceptable to use in library code with no impact on performance when logging is disabled. Advanced users with special requirements are then of course welcome to explore the customisation and extension points of the library. Some common customisations and extensions should be provided. Ok, with that context to my review behind us, I'll move onto the review proper. * What is your evaluation of the design? The design as it currently stands does not allow for the simple use case I outline. That does not mean I think it is failed but I do think it shows some important aspects of the design wanting. I do believe this can be addressed. --- As another reader noted concepts are not namespaces. I have no problem with grouping models of the same concept into the same namespace but that is not the same thing. Importantly concepts are named differently than namespaces. I encourage the author to look at how concepts are used in the standard and try to follow that convention. For example 'writer' is an ok name for a namespace but the concept is probably better named MessageWriter. I believe that the concepts used throughout the library could be better named to provide better clarity. I actually found the naming somewhat confusing at times. --- The omission of log hierarchies, or something that allowed the manipulation of several logs at one time, is an unfortunate omission and forced the library to be particularly heavyweight to use. --- Macros were relied on too much, and I realise the author has agreed to address this concern. --- I felt in general the organisation of the library was lacking and some of the defaults surprised me. If a library is to become part of boost one must expect it to work well with other parts of boost. - the default time handling should use the date_time library with easy selection between local time and UTC (which is often preferred) - threading should use the threading library, there should be no roll-your-own code in this important part of the library - the default path should be boost::filesystem::path --- Log Levels: Logging levels should be expressible as both numbers and names (maybe it is and I missed it). It should be possible to provide different name mappings easily (again maybe it is). The set of default levels should be more comprehensive to support a better out-of-box experience and the syslog levels should be part of that set. From <http://tools.ietf.org/html/rfc3164> Numerical Severity Code 0 Emergency: system is unusable 1 Alert: action must be taken immediately 2 Critical: critical conditions 3 Error: error conditions 4 Warning: warning conditions 5 Notice: normal but significant condition 6 Informational: informational messages 7 Debug: debug-level messages I'd suggest adding also, Fatal Severe Notable Verbose Detail Trace These could be ordered as: Fatal Emergency Alert Critical Severe Error Warning Notice Notable Informational Debug Verbose Detail Trace or some could simply be aliases for others. Regardless I shouldn't need to make modifications to use these common names. I'm not suggesting they all be used, simply that they are available. --- The rolling_log is not as I would expect. In most cases where I have used this I have a naming scheme that places the most recent log as the default log name and older logs should have numerically increasing names. Improving the rolling log behaviour should not pose any real difficulties. --- I got bitten by forgetting to use 'mark_as_initialised()'. This seemed symptomatic of the library as a whole. It was very easy to screw up. That implies to me that the interface was not clean enough, or more especially the default use relied on interfaces with too many variation points making it to easy to make a mistake. --- I am concerned about other aspects of the library, but most of these are covered in other reviews. Apologies for not recounting them here, but my time is short. I would say that I would like to see some co-operation between John and Andrey Semashev or at least some of the discussion from Andrey's review explored further particularly with regard to attributes. I am not saying I agree with Andrey, I am merely saying that it would be nice if some more concrete conclusion could be reached. I recognise also that there is likely no one best solution. * What is your evaluation of the implementation? The implementation needs tidied up. I realise this is a work in progress so that in itself is not a big criticism. The code is somewhat dense, hard to read, and the author seems averse to names which spell out what he means. I really see no need for short and cryptic names. Other reviewers have mentioned other things like line lengths and so on. As a side note I strongly encourage the author to install VirtualBox or similar on his Windows machine so he can install Linux as an alternative platform to try this on. * What is your evaluation of the documentation? The documentation has already been discussed at length regarding use of language structure and so on. I'd like to add my voice to those that wanted a clearer structure with more formal language. I'd also like to see that the documentation is easier to navigate. I saw no way to step through topics without having to go back to the main contents page. Some performance comparisons with other libraries may be in order. I am most interested in the case of disabled logging. Once I am actually logging something I am less concerned. At that time I care most about the information I log more than how quick it was (but of course quicker is better). One to three letter names in examples are not acceptable. What does g_l mean? I can *only* guess. * What is your evaluation of the potential usefulness of the library? This is a very important library of immense potential use. Moreover, if for some reason any future boost library itself was complex enough to warrant adding logging to, then this would be the library used. Of course that puts it into the same category as Boost.Test in terms of stability and core 'fit-for-purpose' needs. * Did you try to use the library? With what compiler? Did you have any problems? Yes, gcc 4.2.3, Debian Sid. I didn't encounter any real problems that haven't already been addressed in other reviews. * How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? I added logging to a new project and used the log files produced to help track down a problem. I spent time trying to use the library and read the docs to help me with that. I spent a little time looking at the implementation to see if I could make small changes to enable capabilities I saw lacking. * Are you knowledgeable about the problem domain? Somewhat. * Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. I've been very encouraged by John's willingness to take on board suggestions and criticisms of his library. His clear enthusiasm to produce a great logging library is very evident. In many ways I'd like to vote yes and let John simply address all the concerns of the library (as he appears both capable of and willing to do). However I think this library is just too important for that to be acceptable. There are other efforts to produce a logging library for boost but so far only John has managed to get a library to review, twice. By and large both libraries have been good ones but both fell short for one reason and another. I think both John and the community has learned a lot from these reviews. I know I certainly learned of some use cases that I had never thought of. I do think John will be able to address most if not all of these with his library. What I would like to see, if possible, is for some of the current efforts on logging to learn from this review and either, join with John to help produce a better library, or get their library ready and into the review queue. As I said at the beginning I have been using John's previous library for some time now and with some success. This new library departed from the first revision perhaps too far for my liking, but once again John has encouraged a good discussion on the topic of a boost.logging library. This is all a very round-about way of saying that I vote Not To Accept this library into boost. But I would like to qualify that. I think the changes that John needs to make are too numerous to warrant a 'yes and tidy-up' vote. I believe there has to be another review. I would be very confident though in a positive outcome of such a review (from my perspective) if John succeeds in addressing the issues raised during review. This can only lead to a better library. I therefore encourage John not to wait too long before asking for his changes to be given a review. I'm sure it won't be a problem getting a review manager. Jamie

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