July 2014 - Boost-users - lists.preview.boost.org

[ptr container] up to date?
by Michael Powell 22 Jul '14

22 Jul '14

Hello, I am considering putting Boost Pointer Container to use in an application to help with, among other things, the polymorphic slicing issue. I've got a domain model which potentially has exactly that creeping in, vector of shared_ptr to base class, with heterogeneous vector composition. http://www.boost.org/doc/libs/1_55_0/libs/ptr_container/doc/ptr_container.h… I was reading a lot of references to std::auto_ptr, which is a deprecated feature these days (http://www.cplusplus.com/reference/memory/auto_ptr/). Also the last update was in 2007 or thereabouts. Is this up to date with current language features such as std's?, i.e. std::unique_ptr, std::shared_ptr? Just generally, this is a fitness for use query. Thank you... Best regards, Michael Powell

2 1

[1.56.0] Beta 1 Available
by Marshall Clow 22 Jul '14

22 Jul '14

Boost release 1.56.0 beta 1 is now available from SourceForge See http://sourceforge.net/projects/boost/files/boost/1.56.0.beta.1/ This release contains 2 new libraries: * Align: Memory alignment functions, allocators, and adaptors, from Glen Fernandes. * Type_Index: Runtime/Compile time copyable type info, from Antony Polukhin. Modularization Boost version control has migrated to a system using git submodules. This shouldn't make too much of a difference to users, although the directory structure is now a bit different. Parts of some libraries have been moved into different modules, and several new modules have been extracted from existing code. All header paths should remain the same. The new modules are: * Assert: Customizable assert macros. Maintained by Peter Dimov. * Core: Core utilities used by other libraries, with minimal dependencies. Maintained by Peter Dimov, Glen Fernandes and Andrey Semashev. * Lexical_Cast: General literal text conversions, such as an int represented a string, or vice-versa, from Kevlin Henney. * Throw_Exception: A common infrastructure for throwing exceptions from Boost libraries, from Emil Dotchevski. * Winapi: Windows API declarations without <windows.h>, for internal Boost use. For details of what's in the release, see http://www.boost.org/users/history/version_1_56_0.html. Note that the links to files on this web page are for the final release - use the SourceForge link above to get the beta files. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

9 12

Building modular-boost on windows with masm32?
by Alle Meije Wink 22 Jul '14

22 Jul '14

Dear all, I have tried to build modular-boost on windows (win7 64bit) using the mingw toolset. The steps that I followed (after some trial & error) are: 1. clone boost-modular from into %home%\usr\local\boost 2. in that boost directory; type bootstrap mingw ===========output=============== Building Boost.Build engine Bootstrapping is done. To build, run: .\b2 To adjust configuration, edit 'project-config.jam'. Further information: - Command line help: .\b2 --help - Getting started guide: http://boost.org/more/getting_started/windows.html - Boost.Build documentation: http://www.boost.org/boost-build2/doc/html/index.html ================================ 3. after apparently successful bootstrap, type b2 -a -d+2 -q --prefix=c:\users\amwink\usr\local --build-type=complete --build-dir=build toolset=gcc link=shared runtime-link=shared The output is below. So the commands cl.exe and ml.exe, which are not in mingw but can be used from the masm32 package are found, but their output is not recognised (as I understand) Is that correct? Would there be a way around this other than installing VC++? Many thanks Alle Meije ===========output=============== Building the Boost C++ Libraries. Performing configuration checks - symlinks supported : yes (cached) - 32-bit : yes (cached) - arm : no (cached) - mips1 : no (cached) - power : no (cached) - sparc : no (cached) - x86 : yes (cached) - has_icu builds : no (cached) warning: Graph library does not contain MPI-based parallel components. note: to enable them, add "using mpi ;" to your user-config.jam - zlib : no (cached) - iconv (libc) : no (cached) - iconv (separate) : yes (cached) - icu : no (cached) - icu (lib64) : no (cached) - g++ -shared-* supported : no (cached) - message-compiler : no (cached) - compiler-supports-ssse3 : yes (cached) - compiler-supports-avx2 : yes (cached) - gcc visibility : yes (cached) - long double support : yes (cached) warning: skipping optional Message Passing Interface (MPI) library. note: to enable MPI support, add "using mpi ;" to user-config.jam. note: to suppress this message, pass "--without-mpi" to bjam. note: otherwise, you can safely ignore this message. warning: No python installation configured and autoconfiguration note: failed. See http://www.boost.org/libs/python/doc/building.html note: for configuration instructions or pass --without-python to note: suppress this message and silently skip all Boost.Python targets - zlib : no (cached) - zlib : no (cached) warning: Skipping Boost.Locale library with threading=single. warning: Skipping Boost.Thread library with threading=single. warning: Skipping Boost.Wave library with threading=single. - zlib : no (cached) Component configuration: - atomic : building - chrono : building - container : building - context : building - coroutine : building - date_time : building - exception : building - filesystem : building - graph : building - graph_parallel : building - iostreams : building - locale : building - log : building - math : building - mpi : building - program_options : building - python : building - random : building - regex : building - serialization : building - signals : building - sync : building - system : building - test : building - thread : building - timer : building - wave : building gcc.compile.c++ build\boost\bin.v2\libs\atomic\build\gcc-mingw-4.8.1\release\threading-multi\lockpool.o "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -mthreads -DBOOST_ALL_NO_LIB=1 -DBOOST_ATOMIC_DYN_LINK=1 -DBOOST_ATOMIC_SOURCE -DBOOST_USE_WINDOWS_H -DNDEBUG -D_WIN32_WINNT=0x0500 -I"." -c -o "build\boost\bin.v2\libs\atomic\build\gcc-mingw-4.8.1\release\threading-multi\lockpool.o" "libs\atomic\src\lockpool.cpp" gcc.link.dll build\boost\bin.v2\libs\atomic\build\gcc-mingw-4.8.1\release\threading-multi\libboost_atomic-mgw48-mt-1_56.dll.a "g++" "-Wl,--out-implib,build\boost\bin.v2\libs\atomic\build\gcc-mingw-4.8.1\release\threading-multi\libboost_atomic-mgw48-mt-1_56.dll.a" -o "build\boost\bin.v2\libs\atomic\build\gcc-mingw-4.8.1\release\threading-multi\libboost_atomic-mgw48-mt-1_56.dll" -shared -Wl,--start-group "build\boost\bin.v2\libs\atomic\build\gcc-mingw-4.8.1\release\threading-multi\lockpool.o" -Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group -mthreads -lkernel32 common.copy stage\lib\libboost_atomic-mgw48-mt-1_56.dll.a copy /b "build\boost\bin.v2\libs\atomic\build\gcc-mingw-4.8.1\release\threading-multi\libboost_atomic-mgw48-mt-1_56.dll.a" + this-file-does-not-exist-A698EE7806899E69 "stage\lib\libboost_atomic-mgw48-mt-1_56.dll.a" build\boost\bin.v2\libs\atomic\build\gcc-mingw-4.8.1\release\threading-multi\libboost_atomic-mgw48-mt-1_56.dll.a 1 file(s) copied. common.copy stage\lib\libboost_atomic-mgw48-mt-1_56.dll copy /b "build\boost\bin.v2\libs\atomic\build\gcc-mingw-4.8.1\release\threading-multi\libboost_atomic-mgw48-mt-1_56.dll" + this-file-does-not-exist-A698EE7806899E69 "stage\lib\libboost_atomic-mgw48-mt-1_56.dll" build\boost\bin.v2\libs\atomic\build\gcc-mingw-4.8.1\release\threading-multi\libboost_atomic-mgw48-mt-1_56.dll 1 file(s) copied. gcc.compile.c++ build\boost\bin.v2\libs\system\build\gcc-mingw-4.8.1\release\threading-multi\error_code.o "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -pedantic -mthreads -DBOOST_ALL_NO_LIB=1 -DBOOST_SYSTEM_DYN_LINK=1 -DNDEBUG -I"." -c -o "build\boost\bin.v2\libs\system\build\gcc-mingw-4.8.1\release\threading-multi\error_code.o" "libs\system\src\error_code.cpp" gcc.link.dll build\boost\bin.v2\libs\system\build\gcc-mingw-4.8.1\release\threading-multi\libboost_system-mgw48-mt-1_56.dll.a "g++" "-Wl,--out-implib,build\boost\bin.v2\libs\system\build\gcc-mingw-4.8.1\release\threading-multi\libboost_system-mgw48-mt-1_56.dll.a" -o "build\boost\bin.v2\libs\system\build\gcc-mingw-4.8.1\release\threading-multi\libboost_system-mgw48-mt-1_56.dll" -shared -Wl,--start-group "build\boost\bin.v2\libs\system\build\gcc-mingw-4.8.1\release\threading-multi\error_code.o" -Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group -mthreads common.copy stage\lib\libboost_system-mgw48-mt-1_56.dll.a copy /b "build\boost\bin.v2\libs\system\build\gcc-mingw-4.8.1\release\threading-multi\libboost_system-mgw48-mt-1_56.dll.a" + this-file-does-not-exist-A698EE7806899E69 "stage\lib\libboost_system-mgw48-mt-1_56.dll.a" build\boost\bin.v2\libs\system\build\gcc-mingw-4.8.1\release\threading-multi\libboost_system-mgw48-mt-1_56.dll.a 1 file(s) copied. common.copy stage\lib\libboost_system-mgw48-mt-1_56.dll copy /b "build\boost\bin.v2\libs\system\build\gcc-mingw-4.8.1\release\threading-multi\libboost_system-mgw48-mt-1_56.dll" + this-file-does-not-exist-A698EE7806899E69 "stage\lib\libboost_system-mgw48-mt-1_56.dll" build\boost\bin.v2\libs\system\build\gcc-mingw-4.8.1\release\threading-multi\libboost_system-mgw48-mt-1_56.dll 1 file(s) copied. gcc.compile.c++ build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\chrono.o "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -pedantic -mthreads -Wextra -Wno-long-long -Wno-variadic-macros -pedantic -DBOOST_ALL_DYN_LINK=1 -DBOOST_ALL_NO_LIB=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_SYSTEM_NO_DEPRE CATED -DNDEBUG -I"." -c -o "build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\chrono.o" "lib s\chrono\src\chrono.cpp" gcc.compile.c++ build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\thread_clock.o "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -pedantic -mthreads -Wextra -Wno-long-long -Wno -variadic-macros -pedantic -DBOOST_ALL_DYN_LINK=1 -DBOOST_ALL_NO_LIB=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_SYSTEM_NO_DEPRECATED -DNDEBUG -I"." -c -o "build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\thread_clock.o " "libs\chrono\src\thread_clock.cpp" gcc.compile.c++ build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\process_cpu_clocks.o "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -pedantic -mthreads -Wextra -Wno-long-long -Wno-variadic-macros -pedantic -DBOOST_ALL_DYN_LINK=1 -DBOOST_ALL_NO_LIB=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_SYSTEM_NO_DEPRE CATED -DNDEBUG -I"." -c -o "build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\process_cpu_clocks.o" "libs\chrono\src\process_cpu_clocks.cpp" gcc.link.dll build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\libboost_chrono-mgw48-mt-1_56.dll.a "g++" "-Wl,--out-implib,build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\libboost_chrono-mgw48-mt-1_56.dll.a" -o "build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\libboost_chrono-mgw48-mt-1_56.dll" -shared -Wl,--start-group "build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-m ulti\chrono.o" "build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\thread_clock.o" "build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\process_cpu_clocks.o" "build\boost\bin.v2\libs\system\build\gcc-mingw-4.8.1\release\threading-multi\libboost_system-mgw48-mt-1_56.dll.a" -Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group -mthreads common.copy stage\lib\libboost_chrono-mgw48-mt-1_56.dll.a copy /b "build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\libboost_chrono-mgw48-mt-1_56.dll.a" + this-file-does-not-exist-A698EE7806899E69 "stage\lib\libboost_chrono-mgw48-mt-1_56.dll.a" build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\libboost_chrono-mgw48-mt-1_56.dll.a 1 file(s) copied. common.copy stage\lib\libboost_chrono-mgw48-mt-1_56.dll copy /b "build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\libboost_chrono-mgw48-mt-1_56.dll" + this-file-does-not-exist-A698EE7806899E69 "stage\lib\libboost_chrono-mgw48-mt-1_56.dll" build\boost\bin.v2\libs\chrono\build\gcc-mingw-4.8.1\release\threading-multi\libboost_chrono-mgw48-mt-1_56.dll 1 file(s) copied. gcc.compile.c build\boost\bin.v2\libs\container\build\gcc-mingw-4.8.1\release\threading-multi\alloc_lib.o "g++" -x c -O3 -finline-functions -Wno-inline -Wall -mthreads -DBOOST_ALL_NO_LIB=1 -DBOOST_CONTAINER_DYN_LINK=1 -DN DEBUG -I"." -c -o "build\boost\bin.v2\libs\container\build\gcc-mingw-4.8.1\release\threading-multi\alloc_lib.o" "libs\container\src\alloc_lib.c" gcc.link.dll build\boost\bin.v2\libs\container\build\gcc-mingw-4.8.1\release\threading-multi\libboost_container-mgw48-mt-1_56.dll.a "g++" "-Wl,--out-implib,build\boost\bin.v2\libs\container\build\gcc-mingw-4.8.1\release\threading-multi\libboost_container-mgw48-mt-1_56.dll.a" -o "build\boost\bin.v2\libs\container\build\gcc-mingw-4.8.1\release\threading-multi\libboost_container-mgw48-mt-1_56.dll" -shared -Wl,--start-group "build\boost\bin.v2\libs\container\build\gcc-mingw-4.8.1\release\threading-multi\alloc_lib.o" -Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group -mthreads common.copy stage\lib\libboost_container-mgw48-mt-1_56.dll.a copy /b "build\boost\bin.v2\libs\container\build\gcc-mingw-4.8.1\release\threading-multi\libboost_container-mgw48-mt-1_56.dll.a" + this-file-does-not-exist-A698EE7806899E69 "stage\lib\libboost_container-mgw48-mt-1_56.dll.a" build\boost\bin.v2\libs\container\build\gcc-mingw-4.8.1\release\threading-multi\libboost_container-mgw48-mt-1_56.dll.a 1 file(s) copied. common.copy stage\lib\libboost_container-mgw48-mt-1_56.dll copy /b "build\boost\bin.v2\libs\container\build\gcc-mingw-4.8.1\release\threading-multi\libboost_container-mgw48-mt-1_56.dll" + this-file-does-not-exist-A698EE7806899E69 "stage\lib\libboost_container-mgw48-mt-1_56.dll" build\boost\bin.v2\libs\container\build\gcc-mingw-4.8.1\release\threading-multi\libboost_container-mgw48-mt-1_56.dll 1 file(s) copied. Jamfile<C:\Users\amwink\usr\local\boost\libs\context\build>.masm build\boost\bin.v2\libs\context\build\gcc-mingw-4.8.1\release\address-model-32\architecture-x86\threading-multi\asm\make_i386_ms_pe_masm.o ml /c /Fo"build\boost\bin.v2\libs\context\build\gcc-mingw-4.8.1\release\address-model-32\architecture-x86\threading-multi\asm\make_i386_ms_pe_masm.o" "libs\context\src\asm\make_i386_ms_pe_masm.asm" Microsoft (R) Macro Assembler Version 6.14.8444 Copyright (C) Microsoft Corp 1981-1997. All rights reserved. Assembling: libs\context\src\asm\make_i386_ms_pe_masm.asm Jamfile<C:\Users\amwink\usr\local\boost\libs\context\build>.masm build\boost\bin.v2\libs\context\build\gcc-mingw-4.8.1\release\address-model-32\architecture-x86\threading-multi\asm\jump_i386_ms_pe_masm.o ml /c /Fo"build\boost\bin.v2\libs\context\build\gcc-mingw-4.8.1\release\address-model-32\architecture-x86\threading-multi\asm\jump_i386_ms_pe_masm.o" "libs\context\src\asm\jump_i386_ms_pe_masm.asm" Microsoft (R) Macro Assembler Version 6.14.8444 Copyright (C) Microsoft Corp 1981-1997. All rights reserved. Assembling: libs\context\src\asm\jump_i386_ms_pe_masm.asm gcc.compile.c++ build\boost\bin.v2\libs\context\build\gcc-mingw-4.8.1\release\threading-multi\dummy.o "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -mthreads -DBOOST_ALL_NO_LIB=1 -DBOOST_CONTEXT_DYN_LINK=1 -DBOOST_CONTEXT_SOURCE -DNDEBUG -I"." -c -o "build\boost\bin.v2\libs\context\build\gcc-mingw-4.8.1\release\ threading-multi\dummy.o" "libs\context\src\dummy.cpp" gcc.link.dll build\boost\bin.v2\libs\context\build\gcc-mingw-4.8.1\release\threading-multi\libboost_context-mgw48-mt-1_56.dll.a "g++" "-Wl,--out-implib,build\boost\bin.v2\libs\context\build\gcc-mingw-4.8.1\release\threading-multi\libboost_context-mgw48-mt-1_56.dll.a" -o "build\boost\bin.v2\libs\context\build\gcc-mingw-4.8.1\release\threading-multi\libboost_context-mgw48-mt-1_56.dll" -shared -Wl,--start-group "build\boost\bin.v2\libs\context\build\gcc-mingw-4.8.1\release\address-model-32\architecture-x86\threading-multi\asm\make_i386_ms_pe_masm.o" "build\boost\bin.v2\libs\context\build\gcc-mingw-4.8.1\release\address-model-32\architecture-x86\threading-multi\asm\jump_i386_ms_pe_masm.o" "build\boost\bin.v2\libs\co ntext\build\gcc-mingw-4.8.1\release\threading-multi\dummy.o" -Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group -mthreads build\boost\bin.v2\libs\context\build\gcc-mingw-4.8.1\release\address-model-32\architecture-x86\threading-multi\asm\make_i386_ms_pe_masm.o: file not recognized: File format not recognized collect2.exe: error: ld returned 1 exit status ...skipped <pstage\lib>libboost_context-mgw48-mt-1_56.dll.a for lack of <pbuild\boost\bin.v2\libs\context\build\gcc-ming w-4.8.1\release\threading-multi>libboost_context-mgw48-mt-1_56.dll.a... ...failed updating 1 target... ================================

4 8

[odeint] optional data
by Erik Schultheis 22 Jul '14

22 Jul '14

Dear all, i am simulating particle trajectories, and depending on the data i want to generate i may or may not have to track additional data [boost.ublas c_matrix] along those trajectories. Right now i enable/disable that via a template parameter (so, using std::tuple(vec, vec) or tuple(vec, vec, c_matrix) and fusion_algebra), which has a few drawbacks. The algorithm is already templated to support varying dimensions via a template parameter, so the additional data practically doubles the number of template instantiations for system and all possible observers. This actually got so bad that gcc (mingw gcc 4.8) refuses to compile with debugging enabled. Therefore, i would like to make the switch between tracking the matrix and ignoring it a runtime choice instead of a template parameter. However, the cost of tracking that matrix is quite high (that is why it is optional), but simply disableing the d matrix / dt calculation in the system does not speed up the calculation much (86 s -> 58 s vs 27 s without matrix). A lot of time is spent in adding and multiplying numbers that are not used anywhere, or actually even copying them (e.g std::swap(c_matrix, c_matrix) shows up quite high in gprof (even though i am not sure how reliable the -pg option is in conjunction with -O3)). So what i am asking here is for suggestions how to best let odeint treat the c_matrix as uninitialized memory and never perform any operations on that depending on a runtime parameter. Options i thought of were: * deriving a class from c_matrix and providing my own versions of operator overloads that check a flag: as far as i know, boost.ublas matrices use some template magic to let operators only return expression templates to optimize evaluation if operations are chained, and i would not be sure about how to actually retain that behaviour in case the matrix is tracked. * creating my own algebra class: from what i could tell from a few quick glances into the algebra files, this would probably be conceptually easier than the other option, but would require a lot of repetetive coding. Does anyone have suggestion for a more efficient implementation strategy? Greetings Erik

2 1

[type traits] redefine a type trait
by Michael Powell 21 Jul '14

21 Jul '14

Hello, Question: is there a way to delete or remove a type trait once it has been defined? And/or redefine it? Consider, I've got a default type trait, something like this. template<typename T> struct throws_exceptions { static const bool value = true; }; struct my_object { //does some work with or without exception }; template<> struct throws_exceptions<my_object> { static const bool value = false; } However, in my unit test code, I want to override the default behavior for test purposes. template<> struct throws_exceptions<my_object> { static const bool value = true; } Or just leave the type trait out. Actually, I'm not sure I just considered an answer to my own question. Possibly I need to separate the traits from the underlying things being modified, and leave it as an option whether to include the defaults, or define user-provided traits. Best regards, Michael Powell

1 0

[msm] enque vs defer
by Raj Sambasivan 21 Jul '14

21 Jul '14

Hi boost-users/Christophe, Does enqueue and defer use the same underlying queue, and when i defer can i validate my unit testcase to check on the queue size using get_message_queue_size(). I did a quick test on defer and checking the queue size and it didnt work may be there is something wrong in my test program but wanted to check if anyone tried this out. thank you -raj

2 2

linking err using log
by David Frank 20 Jul '14

20 Jul '14

Has anyone seen this:? boost/log/attributes/attribute_value_impl.hpp:47: undefined reference to `boost::log::v2s_mt_posix::attribute::impl::operator delete(void*, unsigned long)' In function `boost::log::v2s_mt_posix::attributes::attribute_value_impl<boost::posix_time::ptime>::~attribute_value_impl()': Thanks, Dave

1 0

Push-Relabel undirected graph
by Charles Maske 20 Jul '14

20 Jul '14

Hi there, I'm working in a cut-tree implementation of gomoryhu algorithm and I have to compute max-flow on the input graph. I read about efficiency of the push-relabel algorithm and I want to do some tests but I can't get this because all reverse edges have to capacity equals 0. Someone knows one way to workaround this restriction? Other max-flow algorithms in BGL (edmonds-karp and boykov-kolmogorov) don't have this restriction, what do them more fast than push-relabel implementation. Thanks

1 0

Generate random graphs
by Mandy Nour 20 Jul '14

20 Jul '14

Hello all, I need to generate random undirected simple graphs using The Erdos-Rényi methods and to extract its adjacency matrix into an std::vector. -- View this message in context: http://boost.2283326.n4.nabble.com/Generate-random-graphs-tp4665336.html Sent from the Boost - Users mailing list archive at Nabble.com.

1 0

[variant] forward declarations
by Michael Powell 18 Jul '14

18 Jul '14

Hello, I've got some structs in a AST of sorts which the main player in the mix is a node. In at least one of the use cases, one of the variant types must be forward declared at the time the node can be declared. Possibly one or two other similar use cases. Error 2 error C2139: 'xml::xelement' : an undefined class is not allowed as an argument to compiler intrinsic type trait '__is_nothrow_constructible' i:\installs\development\boost.org\1.55.0\boost_1_55_0\stage\include\boost\type_traits\has_nothrow_constructor.hpp 24 1 xml However, I am bumping into C2139, above. Is there any way for variant to work with forward declared structs (or classes, etc)? Or am I just asking too much from C++? I am building against Visual Studio 2013, Boost 1.55. Thank you... Best regards, Michael Powell

2 2