October 2005 - Boost-users - lists.preview.boost.org

using uBLAS with quantity<> (C++TMP)
by Malte Clasen 17 Oct '05

17 Oct '05

Hi, the book "C++ Template Metaprogramming" by Abrahams and Gurtovoy describes a dimensional analyis framework that enables compile-time checking of physical units. For example dividing a length quantity by a time quantity results in a speed quantity. Now it's tempting to use boost uBLAS with these quantities: A position in space can be expressed as a vector of length quantities etc. But there's one problem: "// uBLAS assumes a common return type for all binary arithmetic operators" (traits.hpp, line 42, boost release 1.33) The promote_traits class relies on this when computing the following: static const std::size_t size = sizeof ( type_deduction_detail::test< typename base_type::x_type , typename base_type::y_type >(x + y) // Use x+y to stand of all the arithmetic actions ); This fails for most quantity operations since dividing a length by a length results in a different type than adding them. As a result Visual C++ 7.1 complains about not being able to deduce template arguments. Is there a way to fix this? I'm not that familiar with the internals of uBLAS, I don't even know the purpose of promote_traits. Malte

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date_time: Print Holidays Example
by __PPS__ 17 Oct '05

17 Oct '05

Aren't you supposed to delete new'd objects, or you simply rely that nobody is gonna look/use/copy this piece of code? http://tinyurl.com/8wanl

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Failing to compile Boost.Threads 1.33.0 with Borland C++
by Jarl Lindrud 16 Oct '05

16 Oct '05

Hi, I've just upgraded from 1.32.0 to 1.33.0, and now when I try to build Boost. Threads with Borland C++, I just get a lot of errors, as shown below. I've compiled with several other compilers, and it all went fine. I'm using Borland C++ 5.6, the one that comes with Borland C++Builder 6, and I have no problems building Boost.Threads from the 1.32.0 distribution . The regression test table seems to indicate it should work, so what am I missing? Thanks. ************************************************** E:\Development\boost_1_33_0\libs\thread\build>..\..\..\..\bjam.1.33.0.exe -sTOOL S=borland ...found 556 targets... ...updating 20 targets... borland-C++-action ..\..\..\bin\boost\libs\thread\build\boost_thread.dll\borland \debug\threading-multi\exceptions.obj ..\src\exceptions.cpp: Error E2090 ..\src\exceptions.cpp 71: Qualifier 'thread_exception' is not a clas s or namespace name Error E2040 ..\src\exceptions.cpp 71: Declaration terminated incorrectly Error E2190 ..\src\exceptions.cpp 187: Unexpected } *** 3 errors in Compile *** "H:\Program\Borland\CBuilder6\bin\bcc32" -j5 -g255 -q -c -P -w -Ve -Vx -a8 -b- -DBOOST_THREAD_LIB_NAME=boost_thread -DBOOST_THREAD_BUILD_DLL=1 -v -Od -vi - -tWR -tWD -WM- -tWM -w-8004 -w-8057 -w-8001 -I"..\..\..\bin\boost\libs\threa d\build" -I"H:\Program\Borland\CBuilder6\include" -I"E:\Development\boost_1_33 _0" -o"..\..\..\bin\boost\libs\thread\build\boost_thread.dll\borland\debug\thre ading-multi\exceptions.obj" "..\src\exceptions.cpp" ...failed borland-C++-action ..\..\..\bin\boost\libs\thread\build\boost_thread.d ll\borland\debug\threading-multi\exceptions.obj... borland-C++-action ..\..\..\bin\boost\libs\thread\build\boost_thread.dll\borland \debug\threading-multi\mutex.obj ..\src\mutex.cpp: Error E2312 ..\src\mutex.cpp 44: 'm_critical_section' is not an unambiguous base class of 'mutex' in function mutex::mutex() Error E2451 ..\src\mutex.cpp 46: Undefined symbol 'm_critical_section' in functi on mutex::mutex() Error E2451 ..\src\mutex.cpp 55: Undefined symbol 'm_critical_section' in functi on mutex::~mutex() Error E2451 ..\src\mutex.cpp 63: Undefined symbol 'm_critical_section' in functi on mutex::do_lock() Error E2451 ..\src\mutex.cpp 71: Undefined symbol 'm_critical_section' in functi on mutex::do_unlock() Error E2228 ..\src\mutex.cpp 71: Too many error or warning messages in function mutex::do_unlock() *** 6 errors in Compile *** "H:\Program\Borland\CBuilder6\bin\bcc32" -j5 -g255 -q -c -P -w -Ve -Vx -a8 -b- -DBOOST_THREAD_LIB_NAME=boost_thread -DBOOST_THREAD_BUILD_DLL=1 -v -Od -vi - -tWR -tWD -WM- -tWM -w-8004 -w-8057 -w-8001 -I"..\..\..\bin\boost\libs\threa d\build" -I"H:\Program\Borland\CBuilder6\include" -I"E:\Development\boost_1_33 _0" -o"..\..\..\bin\boost\libs\thread\build\boost_thread.dll\borland\debug\thre ading-multi\mutex.obj" "..\src\mutex.cpp" ...failed borland-C++-action ..\..\..\bin\boost\libs\thread\build\boost_thread.d ll\borland\debug\threading-multi\mutex.obj... borland-C++-action ..\..\..\bin\boost\libs\thread\build\boost_thread.dll\borland \debug\threading-multi\recursive_mutex.obj ..\src\recursive_mutex.cpp: ...interrupted **************************************************

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Which algorith should I use(Boost::reg_ex)?
by Aaron 16 Oct '05

16 Oct '05

I'm writting a program which could evaluate macros in a c++ header file, like this: #define CMD_IS_BASE 0x00001000 #define CMD_GET_ALL_DOMAINNAME (CMD_IS_BASE+0x1) /* Get all domain name from clients*/ After parsing is done, if you input a value(int), the program could tell you the symbol name, symbol meaning (if there is) corresponding to the valude. As to the above example, when you input 1025(or 0x00010001), the program should tell you it's correspond to symbol CMD_GET_ALL_DOMAINNAME, with it's detail comments "get all domain name from clients". I want also this program could parse the following paragraph too: // // MessageId: GL_CAT_SUMMARY // // MessageText: // // Summary%0 // #define GL_CAT_SUMMARY 0x00000002L It's easy to define a regex pattern, then call boost::regex_grep to got all these symbols and their meaning. But what if two formats exist in one header file? I wrote two grepper plug-ins(one is called singleline.dll, the other is McHearder.dll) to find these symbols, which re pattern contains more lines has the high pirioty to be called, then after it's called, the matched string should be erased or be filled with meaningless chars to prevent the later greppers to work on it. See example: The original string: // // MessageId: GL_CAT_SUMMARY // // MessageText: // // Summary%0 // #define GL_CAT_SUMMARY 0x00000002L #define CMD_IS_BASE 0x00001000 First we call McHeader.dll to work on this string, then it grepped: symble:GL_CAT_SUMMARY value: 2 comments:Summary Then the string should be only one lines, ie: #define CMD_IS_BASE 0x00001000 So, how could I achieve that? Could I still use boost::regex_grep? Thanks in advance!

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Build boost using 64 bit flags on hp-ux 11.23 itanium
by Naeem ahmad 15 Oct '05

15 Oct '05

Do any body how to build boost 64 bit version I have tried to use this command to build, but it does not work bjam cflags="-m64" linkflags="-m64" cxxflags="-m64" "-sTOOLS=gcc" install the 32 bit version build ok by default. Naeem Ahmad

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Re: [Boost-users] Errors compiling greg_month.cpp
by D. R. Evans 15 Oct '05

15 Oct '05

A couple of days ago I requested help (below) as to why greg_month.cpp in 1.33.0 was giving errors under VC++ 6.0. Seeing no response, I guess I'll just go back to 1.30.2, which was the version that has been working fine. Sorry to have troubled you. Doc ----- I just upgraded to 1.33.0, and am getting a bunch of compilation errors with the current version of greg_month.cpp: The list of errors starts with: c:\boost\boost_1_33_0\boost\date_time\gregorian\formatters.hpp(34) : error C2977: 'date_formatter' : too many template arguments c:\boost\boost_1_33_0\boost\date_time\date_formatting_limited.hpp(114) : see declaration of 'date_formatter' c:\boost\boost_1_33_0\boost\date_time\gregorian\formatters.hpp(40) : see reference to function template instantiation 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __cdecl boost::gregorian::to_simpl e There are 31 errors in all. Using VC++ 6.0 on XP Service Pack 2. I would appreciate any gentle pointers as to what I might be doing wrong. Doc

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Exception Stack Trace Question.
by Piyush Kapadia 14 Oct '05

14 Oct '05

Though catch(.) statement allows catching exception not associated with any class, it leads to ambiguous condition as there is no way to have any error message with it. Does Boost provide any means to be able to print stack trace when exception is caught ? In spite of many deficiencies with Java, it let's you access stack trace using printStackTrace() and trace out as what happened and how it happened. This is where C++ std::exception is lacking support and one has to look for such improvements from Boost community.

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[spirit] error removal
by Aaron Griffin 14 Oct '05

14 Oct '05

Hi all, This is a contrived example, but the solution should be the same. Assuming I have two rules, like so: section = identifier >> ch_p('{') >> *setting >> ch_p('}'); setting = identifier >> ch_p('=') >> value; // identifier and value are simple, but left off for brevity This should parse something like: somesettings { a = 12 b = "hello whirled" } Now, what I am looking to do is, if the parser fails parsing a value inside a "section", the parsing itself does not fail, but that section itself does. So if I also had: moresettings { this_is_valid = 12345 bigfaterror = 12"hi there"4.3"fewewfewfw" } Then the "somesettings" section would exist in the final AST, but "moresettings" would not. The error handling docs are a bit unclear to me, bit if I were to make a generic functor_parser which kept an error flag, how would I conditionally remove the section based on that value, seeing as it will already be mid-parse (I don't think something like if_p will work). Thanks in advance for any advice. On a side note, if I have a rule similar to (keyword >> identifier), the skip_parser will translate "somekeyword a" into "somekeyworda" and will parse it fine. However, what is to stop someone from removing the whitespace in the original code. With a quick glance, it appears the example c grammar from the spirit site will parse "voidfoo()" just fine due to this. Is there anyway I can tell the skip grammar to force a seperation? Thanks again, Aaron Griffin

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Re: [Boost-users] Compilation errors with Intel Compiler 9.0 for Linux
by Olivier Delalleau 14 Oct '05

14 Oct '05

On 14 Oct 2005, boost-users-request(a)lists.boost.org wrote: > > There are many errors like this one. Again, if I remove the include > > command -I/opt/intel/compiler90/include/c++ > > it works fine. Also if I use the intel 8.0 includes it works fine (but > > not intel 8.1). > > > > Any help fixing these errors (actually, mainly the regex one, as this > > is the library I really need) will be much appreciated :) > > I believe this is fixed for 1.33.1, can you get hold of that from cvs (it's > on the RC_1_33_0 branch), or would you like a zip to test? I'd like to be > sure this really is fixed for the next release as you're not the only one > with the problem. Thank you :) I got the RC_1_33_0 release from the cvs, and regex is now compiling perfectly with the Intel 9.0 includes. Note that the iostreams library is still broken, but I don't really care that much since I don't plan to use it in the near future. Thanks again for the help! -- Olivier

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Compilation errors with Intel Compiler 9.0 for Linux
by Olivier Delalleau 14 Oct '05

14 Oct '05

I'm getting some annoying errors when compiling some of the libraries of Boost 1.33.0 with Intel Compiler 9.0 (icpc (ICC) 9.0 20050811) under Linux. Here is what happens when I try to compile (again after a first try which failed to update all targets): ----------------------------------------------------------------------------------- ../boost-jam-3.1.11-1-linuxx86/bjam -sTOOLS=intel-linux --prefix=/RQusagers/delallea/local --builddir=/RQexec/delallea/boost_1330_90 -sPYTHON_VERSION=2.4 --with-python-root=/usr/network.ALTIX/python-2.4.1 -sINTEL_VERSION=90 -sINTEL_PATH=/opt/intel/compiler90 install Building Boost.Regex with the optional Unicode/ICU support disabled. Please refer to the Boost.Regex documentation for more information (and if you don't know what ICU is then you probably don't need it). ...found 14461 targets... ...updating 104 targets... intel-linux-C++-action /RQexec/delallea/boost_1330_90/bin/boost/libs/iostreams/build/libboost_iostreams.a/intel-linux/debug/file_descriptor.o /RQMNT/exec1/lisa/delallea/boost_src/boost_1_33_0/boost/iostreams/positioning.hpp(45): error: no suitable conversion function from "mbstate_t" to "std::streampos={std::streamoff={long}}" exists return std::streampos(std::mbstate_t(), off); ^ /RQMNT/exec1/lisa/delallea/boost_src/boost_1_33_0/boost/iostreams/positioning.hpp(45): error: expected a ")" return std::streampos(std::mbstate_t(), off); ^ /RQMNT/exec1/lisa/delallea/boost_src/boost_1_33_0/boost/iostreams/positioning.hpp(51): error: no suitable conversion function from "fpos_t" to "boost::iostreams::stream_offset={intmax_t={long}}" exists return pos; ^ /RQMNT/exec1/lisa/delallea/boost_src/boost_1_33_0/boost/iostreams/positioning.hpp(64): error: expression must have class type return fpos_t_to_offset(pos.seekpos()) + ^ /RQMNT/exec1/lisa/delallea/boost_src/boost_1_33_0/boost/iostreams/positioning.hpp(66): error: expression must have class type stream_offset(std::streamoff(pos.seekpos())); ^ compilation aborted for /RQMNT/exec1/lisa/delallea/boost_src/boost_1_33_0/libs/iostreams/build/../src/file_descriptor.cpp (code 2) . /opt/intel/compiler90/bin/iccvars.sh icpc -c -w1 -g -O0 -I"/RQexec/delallea/boost_1330_90/bin/boost/libs/iostreams/build" -I"/RQMNT/exec1/lisa/delallea/boost_src/boost_1_33_0" -I"/RQMNT/exec1/lisa/delallea/boost_src/boost_1_33_0" -o "/RQexec/delallea/boost_1330_90/bin/boost/libs/iostreams/build/libboost_iostreams.a/intel-linux/debug/file_descriptor.o" "/RQMNT/exec1/lisa/delallea/boost_src/boost_1_33_0/libs/iostreams/build/../src/file_descriptor.cpp" ...failed intel-linux-C++-action /RQexec/delallea/boost_1330_90/bin/boost/libs/iostreams/build/libboost_iostreams.a/intel-linux/debug/file_descriptor.o... ----------------------------------------------------------------------------------- Then other similar errors in iostreams... Now, the important detail: I have in my icpc.cfg the following line: -I/opt/intel/compiler90/include/c++ which forces the Intel compiler to (preferably) use its own includes. Otherwise it uses the g++ standard includes and (at least for the file above) compilation works fine. But I would really prefer to be able to compile Boost using only the Intel code (especially since I need this line in my icpc.cfg for some other non-Boost stuff to compile). Then when compiling the regex library I have other errors. Here is an example of what happens with a specific compile line (here I cleaned my icpc.cfg file): ----------------------------------------------------------------------------------- icpc -I/opt/intel/compiler90/include/c++ -c -w1 -DNDEBUG -DNDEBUG -O3 -openmp -I"/RQexec/delallea/boost_1330_90/bin/boost/libs/regex/build" -I"/RQMNT/exec1/lisa/delallea/boost_src/boost_1_33_0" -o "/RQexec/delallea/boost_1330_90/bin/boost/libs/regex/build/libboost_regex.a/intel-linux/release/threading-multi/instances.o" "/RQMNT/exec1/lisa/delallea/boost_src/boost_1_33_0/libs/regex/build/../src/instances.cpp" /RQMNT/exec1/lisa/delallea/boost_src/boost_1_33_0/boost/regex/v4/instances.hpp(84): error #803: function "boost::match_results<BidiIterator, Allocator>::match_results(const boost::match_results<BidiIterator, Allocator> &) [with BidiIterator=const char *, Allocator=std::vector<boost::sub_match<const char *>, std::allocator<boost::sub_match<const char *>>>::allocator_type]" explicitly instantiated more than once template class BOOST_REGEX_DECL match_results< std::basic_string<BOOST_REGEX_CHAR_T>::const_iterator >; ----------------------------------------------------------------------------------- There are many errors like this one. Again, if I remove the include command -I/opt/intel/compiler90/include/c++ it works fine. Also if I use the intel 8.0 includes it works fine (but not intel 8.1). Any help fixing these errors (actually, mainly the regex one, as this is the library I really need) will be much appreciated :) -- Olivier

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[serialization]save object to a previous version
by Li Lirong 14 Oct '05

14 Oct '05

Hi, As I understand, the class versioning system permits a program to load archives created by previous versions of the program. However, is it possible to explicitly save some of objects to a previous version so that previous versions of the program can read the saved archive? Regards, Lirong

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Re: [Boost-users] Report from Mont Tremblant C++ Committee meeting
by Jeff Garland 14 Oct '05

14 Oct '05

On Thu, 13 Oct 2005 12:52:30 -0400, Daryle Walker wrote > On 10/12/05 5:38 AM, "John Maddock" <john(a)johnmaddock.co.uk> wrote: > > [SNIP] > > And for those who think that in-place modification is the way to go: you do > > realise that it's often *slower* than building a new string don't you? > > And what if the string uses more than half of the available space? > (I'm not advocating in-place modification, but just mentioning that > "return a copy" has its flaws too.) That's why the library supports both interfaces -- essentially letting the user decide. Jeff

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Is there a boost way to avoid this macro usage?
by Rush Manbert 13 Oct '05

13 Oct '05

Hi all, I posted this question to comp.lang.c++.moderated and got a single reply that basically said "it looks like you need to use macros", but I thought I would ask the same question here, just in case you MPL folks have some tricks up your boost library sleeves. Basically, I need to make an enum and a static array of structures from one data set and I only know one way to do it, and it involves an amount of "trickiness" that some find disturbing. The original post: In the code shown below, the CODE_TABLE macro is used to insert a sequence of CODE(codeValue) macros. By changing the definition of CODE(codeValue) right before each usage of CODE_TABLE, I can create an enumeration of codeValues, then use the same CODE_TABLE definition to create a static lookup table that can be used to find information about a codeValue, given its numeric value. In this case, I am finding the name of the enumerated value. In the real application, there are a number of other fields available. (As you can probably tell, I have written a lot of C code in my time.) IMHO, the benefit of this technique is that you only maintain CODE_TABLE. All of the required code bits are generated from it. The downside is that Macros are Evil, the macro-that-is-a-list-of-macros is confusing, and you need to carefully redefine CODE(codeValue) in the proper locations. Additionally, the real application will have multiple classes that each define their own CODE_TABLE contents, so making it all work correctly is a little tricky. My question is this: Is there any method available in C++ that can let me do away with the macros while preserving the nice quality that only one data structure needs to be maintained? Something sophisticated and tricky with templates perhaps? I expect that the fact that I stringize the enum name when creating the lookup table makes a macro the only choice. But, since that is only one component in each lookup table entry in the real code, I might be willing to give it up in order to lose the macros. Here is the code example. Contents of foo.h: ----------------- #define CODE_TABLE \ CODE(FooCodeA) \ CODE(FooCodeB) #define CODE(codeValue) codeValue, class foo { public: typedef enum { // Here comes the first use of CODE_TABLE CODE_TABLE } CodesT; foo (CodesT theCode) : m_code (theCode) {} const char *lookup (void) const; const int getCode (void) const {return m_code;} private: CodesT m_code; typedef struct { CodesT theCode; const char *pTheCodeAsString; } CodeLookupTableT; static CodeLookupTableT m_lookupTable[]; }; Contents of foo.cpp: ------------------- #include "foo.h" // Now we redefine CODE so that we can initialize the // static lookup table #undef CODE #define CODE(codeValue) {codeValue, #codeValue}, foo::CodeTableLookupT foo::m_lookupTable[] = { CODE_TABLE }; // The lookup method that finds the string description // from the numeric code const char *foo::lookup (void) const { for (int i = 0; i < (sizeof m_lookupTable)/(sizeof m_lookupTable[0]); ++i) { if (m_lookupTable[i].theCode == m_code) return m_lookupTable[i].pTheCodeAsString; } return "Unknown code value"; } contents of main.cpp: ------------------- #include <iostream> #include "foo.h" using namespace std; int main (int argc, char * const argv[]) { foo myFoo (foo::FooCodeB); cout << "myFoo with code number....: " << myFoo.getCode() << endl << " looks up the code name as: " << myFoo.lookup() << endl; return 0; } Output from running the program: ------------------------------- myFoo with code number....: 1 looks up the code name as: FooCodeB Thanks, Rush

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Hash Map
by Piyush Kapadia 13 Oct '05

13 Oct '05

Is there any faster version of std::map ? I heard there is a faster hashmap implementation, does boost have anything in this regard ?

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[shared_ptr] Two basic questions
by Matthias Kaeppler 13 Oct '05

13 Oct '05

Hello, I have two questions regarding the proper use of boost::shared_ptr; both actually arose after reading http://www.boost.org/libs/smart_ptr/example/shared_ptr_example.cpp 1. In order for some class to work with std::set, you have to supply an operator with "less than" semantics. Why are you instead declaring a "greater than" operator? 2. In your examples, sometimes you're passing a shared_ptr by value, and sometimes by reference-to-const. Which is the better practice? Usually, common pointers are passed by value, but since in shared_ptr a reference counting mechanism keeps track of the copies, maybe it's better to pass it by reference whenever possible? Thanks in advance, Matthias Kaeppler -- Matthias Kaeppler | Tel: +49 631 3405805 Gerhart-Hauptmann-Str. 16a | Mob: +49 176 20108693 D-67663 Kaiserslautern | E-Mail: matthias at finitestate dot org

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[operators] boost::operators-like functionality for methods
by Geoffrey Irving 13 Oct '05

13 Oct '05

Hello, Is it possible to get boost::operator like functionality for general methods? In other words, I'd like to be able to do the following: template<...> struct complete : public ... { void f(){a();} void g(); }; struct C : public complete<...> { void a(); void b(){g();} }; The resulting class C would have methods a,b,g,f. Here C::b refers to the complete::g and complete::f refers to C::a, so the dependencies are circular. It seems like the boost::operators setup can handle this kind of circular dependency, but I'm not how to do it for methods. Thanks, Geoffrey

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MPL map / multi index dependency bug
by Zach Laine 13 Oct '05

13 Oct '05

The following code does not compile using gcc 3.4.3. I tried it with the same results using 1.32 and 1.33. Reversing the order of the #includes fixes the problem. Is this a known order dependency? If so, I couldn't find it documented anywhere. #include <boost/multi_index_container.hpp> #include <boost/mpl/map.hpp> int main() { return 0; } Compiler output: In file included from /usr/local/include/boost-1_33/boost/mpl/map/aux_/begin_end_impl.hpp:20, from /usr/local/include/boost-1_33/boost/mpl/map/map0.hpp:30, from /usr/local/include/boost-1_33/boost/mpl/map/map10.hpp:19, from /usr/local/include/boost-1_33/boost/mpl/map/map20.hpp:19, from /usr/local/include/boost-1_33/boost/mpl/map.hpp:36, from test.cpp:2: /usr/local/include/boost-1_33/boost/mpl/map/aux_/iterator.hpp:41: error: wrong number of template arguments (2, should be 1) /usr/local/include/boost-1_33/boost/mpl/void.hpp:37: error: provided for `template<class T> struct boost::mpl::is_void_' /usr/local/include/boost-1_33/boost/mpl/map/aux_/iterator.hpp:41: error: `type' is not a member of `<declaration error>' /usr/local/include/boost-1_33/boost/mpl/map/aux_/iterator.hpp:41: error: `type' is not a member of `<declaration error>' /usr/local/include/boost-1_33/boost/mpl/map/aux_/iterator.hpp:42: error: template argument 1 is invalid /usr/local/include/boost-1_33/boost/mpl/map/aux_/iterator.hpp:44: error: expected `{' before '>' token /usr/local/include/boost-1_33/boost/mpl/map/aux_/iterator.hpp:44: error: expected unqualified-id before '>' token /usr/local/include/boost-1_33/boost/mpl/map/aux_/iterator.hpp:44: error: expected `;' before '>' token /usr/local/include/boost-1_33/boost/mpl/map/aux_/iterator.hpp:62: error: expected nested-name-specifier before "item_by_order" /usr/local/include/boost-1_33/boost/mpl/map/aux_/iterator.hpp:62: error: ISO C++ forbids declaration of `item_by_order' with no type /usr/local/include/boost-1_33/boost/mpl/map/aux_/iterator.hpp:62: error: expected `;' before '<' token

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[Beginner] Setting up a function which generates normally distributed numbers
by Snorre Jakobsen 13 Oct '05

13 Oct '05

Hello I'm sorry if this is answered in the documentation, but I didn't find it. I want a function which returns a normally distributed number. #include <boost/random.hpp> #include <time.h> using namespace boost; double SampleNormal (double mean, double sigma) { mt19937 rng; // select random number generator rng.seed((unsigned int) time(0)); // seconds since 1970 // select desired probability distribution normal_distribution<double> norm_dist(mean, sigma); // bind random number generator to distribution, forming a function variate_generator<mt19937&, normal_distribution<double> > normal_sampler(rng, norm_dist); // sample from the distribution return normal_sampler(); } This (from http://surl.se/tvk) works very well, except if it's invoked (with same parameters) more often than once a second. If so, the generator gets equal seeds and returns equal values. How can I construct my program so the seeding happens only once? My experience with templates is limited, but I do have a grasp of the idea. Thanks for any hints. Snorre Jakobsen, Norway

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thread-safe iostreams - ideas for implementation ?
by marc 12 Oct '05

12 Oct '05

thread-safe iostreams - ideas for implementation ? I am currently experimenting with the boosth thread/mutex libraries, and did notice that the standard io streams are not thread safe. In the boost examples, this is handles by some global mutexes which are locked before writing to cout, cerr. I would like to have some classes which - behave exactly as cout, cerr and named file out streams - are thread safe mutex locked Are there any ideas on how to do this ?? I have the following possibilities in mind: 1) make a wrapper class around ostreams which have assigned a specific file or ostream as a member, make each input to operator<<() locked by a lock to a static mutex. advantage: not that hard to implement disadvantage: when outputting multiple things, like in mutex-cout << 'A' << 'B' << std::endl; another thread can come in between 'A' and 'B'. Not really thread safe, as I would like to have the entire line protected. 2) Make some trickery with manipulators and use the std:: stremas, something like cout << lock << 'A' << 'B' << std::endl << unlock ; advantage: pretty ok syntax (albeit one can forget to unlock!) disadvantage: I really have no idea how to implement in a niece and easy way .. 3) Make some trickery with out-put buffering something like having a class modeled like a stream_buff, which is large enough to hold what's written to the associated streams, and which does write to the cout or file streams in a mutex-locked fashion whenever it's manually flushed. ??? silly or possible ?? 4) finaly, a class having a boring print(std::string) function, which sets a lock on the static mutex advantage: easy-peasy disadvantage: C-print like, needs a new class type for each out-file, as a new static mutex has to be assigned to each out-file No nice C++ straming possible whatever I want to write needs to be converted into a std::string first. implementatio: can be templated by a string parameter which is the name of the file, or 'cout'/'cerr' Probably my ideas are not very bright, so I would appreciate some input from boost::thread users, which undoubtely have met the same problem before. Cheers, Marc -- Marc Cromme, cand. polyt, Ph.D Senior Developer, Project Manager Index Data Aps Købmagergade 43, 2 1150 Copenhagen K. Denmark tel: +45 3341 0100 fax: +45 3341 0101 http://www.indexdata.com INDEX DATA Means Business for Open Source and Open Standards

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[Review] TR1 library accepted
by Beman Dawes 12 Oct '05

12 Oct '05

John Maddock's TR1 library is accepted by Boost. Coincidentally, ISO has just announced that TR1 unanimously passed its final ballot, and so is now official. There were four reviews of John's submission, all urging acceptance. For most of the relatively few issues raised during review, John has already responded. Unless I missed it, however, John hasn't responded to Jonathan Wakely's review comments yet, anduld do so when he gets a chance. For example: It might be useful to list all the BOOST_HAS_TR1_XXX macros on the Configuration page, so you can glance at them all at once (most people will know what components each macro relates to.) Otherwise you have to read through a lot of text on the "TR1 By Subject" page to see what's available. Congratulations to John, and thanks to our reviewers! --Beman Dawes, Review Manager

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compiling fails on MacOS X
by Ákos Maróy 12 Oct '05

12 Oct '05

Hi, I'm trying to compile boost 1.33 on MacOS X, and I get a number of failures. I have: $ uname -a Darwin akos-maroys-mac-mini.local 8.2.0 Darwin Kernel Version 8.2.0: Fri Jun 24 17:46:54 PDT 2005; root:xnu-792.2.4.obj~3/RELEASE_PPC Power Macintosh powerpc $ gcc --version powerpc-apple-darwin8-gcc-4.0.0 (GCC) 4.0.0 (Apple Computer, Inc. build 5026) Copyright (C) 2005 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. I compiled bjam first (without problems), and then issues the following command (according to the documentation): ./tools/build/jam_src/bin.macosxppc/bjam -sTOOLS=darwin --prefix=/tmp/boost I get the following errors: darwin-Archive-action bin/boost/libs/regex/build/libboost_regex.a/darwin/release/libboost_regex-1_33.a ranlib: file: bin/boost/libs/regex/build/libboost_regex.a/darwin/release/libboost_regex-1_33.a(icu.o) has no symbols ranlib: file: bin/boost/libs/regex/build/libboost_regex.a/darwin/release/libboost_regex-1_33.a(regex_debug.o) has no symbols ranlib: file: bin/boost/libs/regex/build/libboost_regex.a/darwin/release/libboost_regex-1_33.a(w32_regex_traits.o) has no symbols ranlib: file: bin/boost/libs/regex/build/libboost_regex.a/darwin/release/libboost_regex-1_33.a(usinstances.o) has no symbols system-Ranlib bin/boost/libs/regex/build/libboost_regex.a/darwin/release/libboost_regex-1_33.a ranlib: file: bin/boost/libs/regex/build/libboost_regex.a/darwin/release/libboost_regex-1_33.a(icu.o) has no symbols ranlib: file: bin/boost/libs/regex/build/libboost_regex.a/darwin/release/libboost_regex-1_33.a(regex_debug.o) has no symbols ranlib: file: bin/boost/libs/regex/build/libboost_regex.a/darwin/release/libboost_regex-1_33.a(w32_regex_traits.o) has no symbols ranlib: file: bin/boost/libs/regex/build/libboost_regex.a/darwin/release/libboost_regex-1_33.a(usinstances.o) has no symbols darwin-Link-DyLib-action bin/boost/libs/test/build/libboost_prg_exec_monitor.dylib/darwin/debug/shared-linkable-true/libboost_prg_exec_monitor-d-1_33.dylib ld: Undefined symbols: __Z8cpp_mainiPPc /usr/bin/libtool: internal link edit command failed ...failed darwin-Link-DyLib-action bin/boost/libs/test/build/libboost_prg_exec_monitor.dylib/darwin/debug/shared-linkable-true/libboost_prg_exec_monitor-d-1_33.dylib... darwin-Link-DyLib-action bin/boost/libs/test/build/libboost_prg_exec_monitor.dylib/darwin/release/shared-linkable-true/libboost_prg_exec_monitor-1_33.dylib ld: Undefined symbols: __Z8cpp_mainiPPc /usr/bin/libtool: internal link edit command failed ...failed darwin-Link-DyLib-action bin/boost/libs/test/build/libboost_prg_exec_monitor.dylib/darwin/release/shared-linkable-true/libboost_prg_exec_monitor-1_33.dylib... darwin-Link-DyLib-action bin/boost/libs/test/build/libboost_test_exec_monitor.dylib/darwin/debug/shared-linkable-true/libboost_test_exec_monitor-d-1_33.dylib ld: Undefined symbols: __Z9test_mainiPPc /usr/bin/libtool: internal link edit command failed ...failed darwin-Link-DyLib-action bin/boost/libs/test/build/libboost_test_exec_monitor.dylib/darwin/debug/shared-linkable-true/libboost_test_exec_monitor-d-1_33.dylib... darwin-Link-DyLib-action bin/boost/libs/test/build/libboost_test_exec_monitor.dylib/darwin/release/shared-linkable-true/libboost_test_exec_monitor-1_33.dylib ld: Undefined symbols: __Z9test_mainiPPc /usr/bin/libtool: internal link edit command failed ...failed darwin-Link-DyLib-action bin/boost/libs/test/build/libboost_test_exec_monitor.dylib/darwin/release/shared-linkable-true/libboost_test_exec_monitor-1_33.dylib... darwin-Link-DyLib-action bin/boost/libs/test/build/libboost_unit_test_framework.dylib/darwin/debug/shared-linkable-true/libboost_unit_test_framework-d-1_33.dylib ld: Undefined symbols: __Z20init_unit_test_suiteiPPc /usr/bin/libtool: internal link edit command failed ...failed darwin-Link-DyLib-action bin/boost/libs/test/build/libboost_unit_test_framework.dylib/darwin/debug/shared-linkable-true/libboost_unit_test_framework-d-1_33.dylib... darwin-Link-DyLib-action bin/boost/libs/test/build/libboost_unit_test_framework.dylib/darwin/release/shared-linkable-true/libboost_unit_test_framework-1_33.dylib ld: Undefined symbols: __Z20init_unit_test_suiteiPPc /usr/bin/libtool: internal link edit command failed

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Errors compiling greg_month.cpp
by D. R. Evans 12 Oct '05

12 Oct '05

I just upgraded to 1.33.0, and am getting a bunch of compilation errors with the current version of greg_month.cpp: The list of errors starts with: c:\boost\boost_1_33_0\boost\date_time\gregorian\formatters.hpp(34) : error C2977: 'date_formatter' : too many template arguments c:\boost\boost_1_33_0\boost\date_time\date_formatting_limited.hpp(114) : see declaration of 'date_formatter' c:\boost\boost_1_33_0\boost\date_time\gregorian\formatters.hpp(40) : see reference to function template instantiation 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __cdecl boost::gregorian::to_simpl e There are 31 errors in all. Using VC++ 6.0 on XP Service Pack 2. I would appreciate any gentle pointers as to what I might be doing wrong. Doc

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Short Mailing List Outage on Thursday 10/13
by Jeff Garland 12 Oct '05

12 Oct '05

FYI -- I believe this will impact Boost-Users as well. ------------------ I am sorry for this short notice but I need to reboot milliways to upgrade its firmware. It will be down for about 1 hour Thursday morning (10/13). - 6:00am-7:00am Pacific US time - 7:00am-8:00am Mountain US time - 8:00am-9:00am Central US time - 9:00am-10:00am Eastern US time - 1:00pm-2:00pm GMT Specifically, the following services provided by the OSL will be unavailable during this timeframe: - All e-mail services - Incoming mail (including all mailman list hosting) - Outgoing mail (including all mailman list hosting) - IMAP/SSL - All web hosting - lists.boost.org - ...and all others hosted by the OSL

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typeof
by Karl Meerbergen 12 Oct '05

12 Oct '05

Hello, Looking at the regression test results, it seems that some typeof tests do not compile on IBM. Did somebody have a look at this? Is this a known problem? Thanks, Karl

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Crash when assign value to regex object
by Aaron 12 Oct '05

12 Oct '05

The code snippet: struct Grepper { int nPriority; boost::regex re; pONGREPFOUNDCALLBACK pOnGrepFoundSymbols; friend bool operator< (const Grepper& g1, const Grepper& g2) { return g1.nPriority > g2.nPriority; } }; if (...){ Grepper gp; if (QueryGreppers(gp)) g_vecGreppers.push_back(gp); } bool QueryGreppers(Grepper& gp) { gp.nPriority = 1; gp.re ="\\s*#define\\s+([^\\s]+)\\s+([^/\\r\\n]+)([^\\r\\n]*)"; gp.pOnGrepFoundSymbols = OnGrepSingleLineSymbols; return true; } Program fails at gp.re = ... The call stack is: _CrtIsValidHeapPointer(const void * 0x012e61f8) line 1606 _free_dbg_lk(void * 0x012e61f8, int 1) line 1011 + 9 bytes _free_dbg(void * 0x012e61f8, int 1) line 970 + 13 bytes free(void * 0x012e61f8) line 926 + 11 bytes operator delete(void * 0x012e61f8) line 7 + 9 bytes boost::detail::simple_alloc::deallocate(void * 0x012e61f8, unsigned int 1024) line 213 + 9 bytes boost::detail::allocator_adapter<unsigned char,boost::detail::simple_alloc>::deallocate(unsigned char * 0x012e61f8, unsigned int 1024) line 258 boost::re_detail::raw_storage<boost::detail::allocator_adapter<char,boost::detail::simple_alloc> >::resize(boost::re_detail::raw_storage<boost::detail::allocator_adapter<char,boost::detail::simple_alloc> > * const 0x0012eff0, unsigned int 1120) line 223 boost::re_detail::raw_storage<boost::detail::allocator_adapter<char,boost::detail::simple_alloc> >::extend(boost::re_detail::raw_storage<boost::detail::allocator_adapter<char,boost::detail::simple_alloc> > * const 0x0012eff0, unsigned int 268) line 131 + 27 bytes boost::reg_expression<char,boost::regex_traits<char>,boost::detail::allocator_adapter<char,boost::detail::simple_alloc> >::compile_set_aux(boost::reg_expression<char,boost::regex_traits<char>,boost::detail::allocator_adapter<char,boost::detail::simple_alloc> > * const 0x0012efe8, ...) line 1145 + 17 bytes boost::reg_expression<char,boost::regex_traits<char>,boost::detail::allocator_adapter<char,boost::detail::simple_alloc> >::compile_set_simple(boost::reg_expression<char,boost::regex_traits<char>,boost::detail::allocator_adapter<char,boost::detail::simple_alloc> > * const 0x0012efe8, boost::re_detail::re_syntax_base * 0x012e6534, unsigned long 8, unsigned char 0) line 737 + 48 bytes boost::reg_expression<char,boost::regex_traits<char>,boost::detail::allocator_adapter<char,boost::detail::simple_alloc> >::set_expression(boost::reg_expression<char,boost::regex_traits<char>,boost::detail::allocator_adapter<char,boost::detail::simple_alloc> > * const 0x0012efe8, const char * 0x0846601c `string', const char * 0x08466049, unsigned int 34055) line 1651 + 20 bytes boost::reg_expression<char,boost::regex_traits<char>,boost::detail::allocator_adapter<char,boost::detail::simple_alloc> >::set_expression(boost::reg_expression<char,boost::regex_traits<char>,boost::detail::allocator_adapter<char,boost::detail::simple_alloc> > * const 0x0012efe8, const char * 0x0846601c `string', unsigned int 34055) line 238 + 59 bytes boost::reg_expression<char,boost::regex_traits<char>,boost::detail::allocator_adapter<char,boost::detail::simple_alloc> >::assign(const char * 0x0846601c `string', unsigned int 33031) line 89 + 20 bytes boost::basic_regex<char,boost::regex_traits<char>,boost::detail::allocator_adapter<char,boost::detail::simple_alloc> >::operator=(boost::basic_regex<char,boost::regex_traits<char>,boost::detail::allocator_adapter<char,boost::detail::simple_alloc> > * const 0x0012efe8, const char * 0x0846601c `string') line 356 QueryGreppers(Grepper & {...}) line 35 + 17 bytes What's wrong with it?

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