MSVC 2015 update 2

[RiccardoRossi]

Hello,

i wanted to know if there is any possibility of using the library with visual studio 2015 UPDATE 2.

Think is that update 3 is not viable for us, since boost.python is broken.

regards
Riccardo

[nlohmann]

I do not know. We use MSVC 19.0.24215.1 in the unit tests on AppVeyor (see https://ci.appveyor.com/project/nlohmann/json for the latest build result). Did you try? What error message did you get?

[RiccardoRossi]

Hi, my colleague Pooyan Dadvant will be posting the error.

[pooyan-dadvand]

Just to share the error I got while compiling it with my VS build 14.023107.0

1>C:\Kratos\external_libraries\json/json.hpp(887): error C4579: 'nlohmann::detail::static_constnlohmann::detail::to_json_fn::value': in-class initialization for type 'const T' is not yet implemented; static member will remain uninitialized at runtime but use in constant-expressions is supported
1> with
1> [
1> T=nlohmann::detail::to_json_fn
1> ]
1> C:\Kratos\external_libraries\json/json.hpp(898): note: see reference to class template instantiation 'nlohmann::detail::static_constnlohmann::detail::to_json_fn' being compiled
1>C:\Kratos\external_libraries\json/json.hpp(887): error C2131: expression did not evaluate to a constant
1> C:\Kratos\external_libraries\json/json.hpp(887): note: failure was caused by returning the address of or a reference to a temporary
1>C:\Kratos\external_libraries\json/json.hpp(887): error C4579: 'nlohmann::detail::static_constnlohmann::detail::from_json_fn::value': in-class initialization for type 'const T' is not yet implemented; static member will remain uninitialized at runtime but use in constant-expressions is supported
1> with
1> [
1> T=nlohmann::detail::from_json_fn
1> ]
1> C:\Kratos\external_libraries\json/json.hpp(899): note: see reference to class template instantiation 'nlohmann::detail::static_constnlohmann::detail::from_json_fn' being compiled
1>C:\Kratos\external_libraries\json/json.hpp(6482): error C2784: '_Ty *std::begin(_Ty (&)[_Size]) noexcept': could not deduce template argument for '_Ty (&)[_Size]' from 'add_rvalue_reference::type'
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xutility(1250): note: see declaration of 'std::begin'
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\type_traits(761): note: see reference to class template instantiation 'nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer' being compiled
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\type_traits(790): note: see reference to class template instantiation 'std::is_nothrow_constructible<_Ty,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer &&>' being compiled
1> with
1> [
1> _Ty=nlohmann::json
1> ]
1> C:\Kratos\external_libraries\json/json.hpp(12912): note: see reference to class template instantiation 'std::is_nothrow_move_constructiblenlohmann::json' being compiled
1>C:\Kratos\external_libraries\json/json.hpp(6482): error C2893: Failed to specialize function template 'unknown-type std::begin(const _Container &)'
1> C:\Kratos\external_libraries\json/json.hpp(6482): note: With the following template arguments:
1> C:\Kratos\external_libraries\json/json.hpp(6482): note: '_Container=add_rvalue_reference::type'
1>C:\Kratos\external_libraries\json/json.hpp(6482): error C2893: Failed to specialize function template 'unknown-type std::begin(_Container &)'
1> C:\Kratos\external_libraries\json/json.hpp(6482): note: With the following template arguments:
1> C:\Kratos\external_libraries\json/json.hpp(6482): note: '_Container=add_rvalue_reference::type'
1>C:\Kratos\external_libraries\json/json.hpp(6482): error C2784: 'const _Elem *std::begin(std::initializer_list<_Elem>) noexcept': could not deduce template argument for 'std::initializer_list<_Elem>' from 'add_rvalue_reference::type'
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\initializer_list(60): note: see declaration of 'std::begin'
1>C:\Kratos\kratos\includes/kratos_parameters.h(174): error C2665: 'nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse': none of the 2 overloads could convert all the argument types
1> C:\Kratos\external_libraries\json/json.hpp(6361): note: could be 'nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse(std::istream &&,const std::function<bool (int,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse_event_t,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer &)>)'
1> C:\Kratos\external_libraries\json/json.hpp(6352): note: or 'nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse(std::istream &,const std::function<bool (int,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse_event_t,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer &)>)'
1> C:\Kratos\kratos\includes/kratos_parameters.h(174): note: while trying to match the argument list '(const std::string)'
1>C:\Kratos\kratos\includes/kratos_parameters.h(183): error C2665: 'nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse': none of the 2 overloads could convert all the argument types
1> C:\Kratos\external_libraries\json/json.hpp(6361): note: could be 'nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse(std::istream &&,const std::function<bool (int,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse_event_t,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer &)>)'
1> C:\Kratos\external_libraries\json/json.hpp(6352): note: or 'nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse(std::istream &,const std::function<bool (int,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse_event_t,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer &)>)'
1> C:\Kratos\kratos\includes/kratos_parameters.h(183): note: while trying to match the argument list '(const std::string)'
1>C:\Kratos\kratos\includes/kratos_parameters.h(188): error C2665: 'nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse': none of the 2 overloads could convert all the argument types
1> C:\Kratos\external_libraries\json/json.hpp(6361): note: could be 'nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse(std::istream &&,const std::function<bool (int,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse_event_t,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer &)>)'
1> C:\Kratos\external_libraries\json/json.hpp(6352): note: or 'nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse(std::istream &,const std::function<bool (int,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer::parse_event_t,nlohmann::basic_jsonstd::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer &)>)'
1> C:\Kratos\kratos\includes/kratos_parameters.h(188): note: while trying to match the argument list '(const std::string)'

[nlohmann]

Thanks. Could you compile the unit tests?

[pooyan-dadvand]

I have try to compile the unit testing with a clone of the current repository version and gives me the same compilation error.

[nlohmann]

Could you please post the error from compiling the unit tests as well, because then we have the complete picture where the error first occurs.

Well, I am no expert in MSVC. It seems as if AppVeyor is using a slightly more modern version (just comparing the build version numbers). Is that Update 3?

[pooyan-dadvand]

The update 3 is more modern but it is incompatible with boost library which we are using....
I will send you the error when I arrive to my office

[pooyan-dadvand]

here you have the output:

1>------ Build started: Project: ZERO_CHECK, Configuration: Debug Win32 ------
2>------ Skipped Build: Project: RUN_TESTS, Configuration: Debug Win32 ------
2>Project not selected to build for this solution configuration 
1>  Checking Build System
1>  CMake does not need to re-run because C:/Temp/json-develop/build/CMakeFiles/generate.stamp is up-to-date.
1>  CMake does not need to re-run because C:/Temp/json-develop/build/test/CMakeFiles/generate.stamp is up-to-date.
3>------ Build started: Project: catch_main, Configuration: Debug Win32 ------
4>------ Skipped Build: Project: clean_cotire, Configuration: Debug Win32 ------
4>Project not selected to build for this solution configuration 
3>  Building Custom Rule C:/Temp/json-develop/test/CMakeLists.txt
3>  CMake does not need to re-run because C:\Temp\json-develop\build\test\CMakeFiles\generate.stamp is up-to-date.
3>  unit.cpp
3>  catch_main.vcxproj -> C:\Temp\json-develop\build\test\catch_main.dir\Debug\catch_main.lib
5>------ Build started: Project: json_unit, Configuration: Debug Win32 ------
5>  Building Custom Rule C:/Temp/json-develop/test/CMakeLists.txt
5>  CMake does not need to re-run because C:\Temp\json-develop\build\test\CMakeFiles\generate.stamp is up-to-date.
5>  Generating CXX prefix header C:\Temp\json-develop\build\test\Debug\cotire\json_unit_CXX_prefix.hxx
5>  unit-algorithms.cpp
5>C:\Temp\json-develop\src\json.hpp(887): error C4579: 'nlohmann::detail::static_const<nlohmann::detail::to_json_fn>::value': in-class initialization for type 'const T' is not yet implemented; static member will remain uninitialized at runtime but use in constant-expressions is supported
5>          with
5>          [
5>              T=nlohmann::detail::to_json_fn
5>          ]
5>  C:\Temp\json-develop\src\json.hpp(898): note: see reference to class template instantiation 'nlohmann::detail::static_const<nlohmann::detail::to_json_fn>' being compiled
5>C:\Temp\json-develop\src\json.hpp(887): error C2131: expression did not evaluate to a constant
5>  C:\Temp\json-develop\src\json.hpp(887): note: failure was caused by returning the address of or a reference to a temporary
5>C:\Temp\json-develop\src\json.hpp(887): error C4579: 'nlohmann::detail::static_const<nlohmann::detail::from_json_fn>::value': in-class initialization for type 'const T' is not yet implemented; static member will remain uninitialized at runtime but use in constant-expressions is supported
5>          with
5>          [
5>              T=nlohmann::detail::from_json_fn
5>          ]
5>  C:\Temp\json-develop\src\json.hpp(899): note: see reference to class template instantiation 'nlohmann::detail::static_const<nlohmann::detail::from_json_fn>' being compiled
5>C:\Temp\json-develop\src\json.hpp(6482): error C2784: '_Ty *std::begin(_Ty (&)[_Size]) noexcept': could not deduce template argument for '_Ty (&)[_Size]' from 'add_rvalue_reference<const ContiguousContainer>::type'
5>  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xutility(1250): note: see declaration of 'std::begin'
5>  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\type_traits(761): note: see reference to class template instantiation 'nlohmann::basic_json<std::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer>' being compiled
5>  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\type_traits(790): note: see reference to class template instantiation 'std::is_nothrow_constructible<_Ty,nlohmann::basic_json<std::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer> &&>' being compiled
5>          with
5>          [
5>              _Ty=nlohmann::json
5>          ]
5>  C:\Temp\json-develop\src\json.hpp(12931): note: see reference to class template instantiation 'std::is_nothrow_move_constructible<nlohmann::json>' being compiled
5>C:\Temp\json-develop\src\json.hpp(6482): error C2893: Failed to specialize function template 'unknown-type std::begin(const _Container &)'
5>  C:\Temp\json-develop\src\json.hpp(6482): note: With the following template arguments:
5>  C:\Temp\json-develop\src\json.hpp(6482): note: '_Container=add_rvalue_reference<const ContiguousContainer>::type'
5>C:\Temp\json-develop\src\json.hpp(6482): error C2893: Failed to specialize function template 'unknown-type std::begin(_Container &)'
5>  C:\Temp\json-develop\src\json.hpp(6482): note: With the following template arguments:
5>  C:\Temp\json-develop\src\json.hpp(6482): note: '_Container=add_rvalue_reference<const ContiguousContainer>::type'
5>C:\Temp\json-develop\src\json.hpp(6482): error C2784: 'const _Elem *std::begin(std::initializer_list<_Elem>) noexcept': could not deduce template argument for 'std::initializer_list<_Elem>' from 'add_rvalue_reference<const ContiguousContainer>::type'
5>  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\initializer_list(60): note: see declaration of 'std::begin'
6>------ Build started: Project: ALL_BUILD, Configuration: Debug Win32 ------
6>  Building Custom Rule C:/Temp/json-develop/CMakeLists.txt
6>  CMake does not need to re-run because C:\Temp\json-develop\build\CMakeFiles\generate.stamp is up-to-date.
7>------ Skipped Build: Project: INSTALL, Configuration: Debug Win32 ------
7>Project not selected to build for this solution configuration 
========== Build: 3 succeeded, 1 failed, 0 up-to-date, 3 skipped ==========

[nlohmann]

@theodelrieu Any idea on this? MSVC seems to have an issue with static_const.

[theodelrieu]

I don't know if there is a workaround to that...
You could send a message to the ranges-v3 maintainers to ask them if they encountered this problem before upgrading to Visual 2015, (the static_const machinery comes from them).

You could also try to replace const auto& by auto&& at lines 898-899, but I'm 99% certain it won't help.
Sorry!

[nlohmann]

@pooyan-dadvand Did you try the hack proposed by @theodelrieu?

You could also try to replace const auto& by auto&& at lines 898-899, but I'm 99% certain it won't help.

[pooyan-dadvand]

Not yet... l will do it ASAP!

[pooyan-dadvand]

It did not compiled claiming that the expression is not constant. The error:

3>------ Build started: Project: json_unit, Configuration: Debug Win32 ------
3>  unit-algorithms.cpp
3>C:\Temp\json-develop\src\json.hpp(887): error C4579: 'nlohmann::detail::static_const<nlohmann::detail::to_json_fn>::value': in-class initialization for type 'const T' is not yet implemented; static member will remain uninitialized at runtime but use in constant-expressions is supported
3>          with
3>          [
3>              T=nlohmann::detail::to_json_fn
3>          ]
3>  C:\Temp\json-develop\src\json.hpp(898): note: see reference to class template instantiation 'nlohmann::detail::static_const<nlohmann::detail::to_json_fn>' being compiled
3>C:\Temp\json-develop\src\json.hpp(887): error C2131: expression did not evaluate to a constant
3>  C:\Temp\json-develop\src\json.hpp(887): note: failure was caused by returning the address of or a reference to a temporary
3>C:\Temp\json-develop\src\json.hpp(887): error C4579: 'nlohmann::detail::static_const<nlohmann::detail::from_json_fn>::value': in-class initialization for type 'const T' is not yet implemented; static member will remain uninitialized at runtime but use in constant-expressions is supported
3>          with
3>          [
3>              T=nlohmann::detail::from_json_fn
3>          ]
3>  C:\Temp\json-develop\src\json.hpp(899): note: see reference to class template instantiation 'nlohmann::detail::static_const<nlohmann::detail::from_json_fn>' being compiled
3>C:\Temp\json-develop\src\json.hpp(6482): error C2784: '_Ty *std::begin(_Ty (&)[_Size]) noexcept': could not deduce template argument for '_Ty (&)[_Size]' from 'add_rvalue_reference<const ContiguousContainer>::type'
3>  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xutility(1250): note: see declaration of 'std::begin'
3>  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\type_traits(761): note: see reference to class template instantiation 'nlohmann::basic_json<std::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer>' being compiled
3>  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\type_traits(790): note: see reference to class template instantiation 'std::is_nothrow_constructible<_Ty,nlohmann::basic_json<std::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer> &&>' being compiled
3>          with
3>          [
3>              _Ty=nlohmann::json
3>          ]
3>  C:\Temp\json-develop\src\json.hpp(12931): note: see reference to class template instantiation 'std::is_nothrow_move_constructible<nlohmann::json>' being compiled
3>C:\Temp\json-develop\src\json.hpp(6482): error C2893: Failed to specialize function template 'unknown-type std::begin(const _Container &)'
3>  C:\Temp\json-develop\src\json.hpp(6482): note: With the following template arguments:
3>  C:\Temp\json-develop\src\json.hpp(6482): note: '_Container=add_rvalue_reference<const ContiguousContainer>::type'
3>C:\Temp\json-develop\src\json.hpp(6482): error C2893: Failed to specialize function template 'unknown-type std::begin(_Container &)'
3>  C:\Temp\json-develop\src\json.hpp(6482): note: With the following template arguments:
3>  C:\Temp\json-develop\src\json.hpp(6482): note: '_Container=add_rvalue_reference<const ContiguousContainer>::type'
3>C:\Temp\json-develop\src\json.hpp(6482): error C2784: 'const _Elem *std::begin(std::initializer_list<_Elem>) noexcept': could not deduce template argument for 'std::initializer_list<_Elem>' from 'add_rvalue_reference<const ContiguousContainer>::type'
3>  C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\initializer_list(60): note: see declaration of 'std::begin'
4>------ Skipped Build: Project: INSTALL, Configuration: Debug Win32 ------
4>Project not selected to build for this solution configuration 
========== Build: 0 succeeded, 1 failed, 3 up-to-date, 3 skipped ==========

[nlohmann]

@pooyan-dadvand This is a pity, but I think we cannot help you right now.

[RiccardoRossi]

Hi Niels, shame to hear this.
Just one more question before i give up: wouldn't it be possible to make a copy instead of passing a const reference? guess it would be slower, but if that works i would pay that price to preserve backward compatibility.
(please be patient if the suggestion is stupid)

[theodelrieu]

@RiccardoRossi are you talking about the static_const?

[RiccardoRossi]

Yes El 5 mar. 2017 6:12 p. m., "Théo DELRIEU" <notifications@github.com> escribió:

…

@RiccardoRossi <https://github.com/RiccardoRossi> are you talking about the static_const? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#469 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AHr7Eboqi-uxkzahU9BvgfDZEefP43maks5riuz1gaJpZM4MKLeg> .

[theodelrieu]

Well, it's not gonna help, if I remember correctly, the point of being a reference in an anonymous namespace is to prevent ODR-violation.

You can read this Eric Niebler's blog post to know the very details (I don't remember all of them)

I hope the next MSVC release will solve your Boost.Python problems

[pooyan-dadvand]

Hope so!

Time will solve everything, even MSVC problems!

Thanks.

[nlohmann]

I close this issue here as there is nothing we can do. @RiccardoRossi @pooyan-dadvand it would be great if you could give us feedback whether this issue eventually was resolved.

[RiccardoRossi]

Hi Niels,
we do not have a workaround for this. MSVC2017 works both for your code and for ours, but we can not enforce it as a requirement.
My hope is that an update4 comes out for msvc2015 fixing the outstanding issues with boost, however there is not much more we can do. For the moment we are using rapidjson internally so not a blocker, just a shame since i liked much more your lib.

in any case thank you for your time and effort.

[ai0376]

vs community 2015 run ok!

[pooyan-dadvand]

Good news! Thanks for notification!

@RiccardoRossi we should give it another try then

[nlohmann]

@mjrao I am not using MSVC myself. Is "vs community 2015" something different than "msvc2015"?

[gregmarr]

Visual Studio Community 2015 is the same as Visual Studio Professional 2015 but with a different license.

[nlohmann]

Thanks for the info. So I can keep the README as is, because there is no additional supported compiler or version.

[ai0376]

@nlohmann Thanks for your reply! Compile failed in VS 2015 Enterprise and VS 2015 Professional, but compiled successfully in VS 2015 Community. I don't know what happened. Compile error is as follows:
"nlohmann::detail::static_constnlohmann::detail::to_json_fn::value': in-class initialization for type 'const T' is not yet implemented; static member will remain uninitialized at runtime but use in constant-expressions is supported..."

[nlohmann]

Can you try the develop version and provide the complete error message with line numbers?

[gregmarr]

@mjrao Are you sure you're using the same update version and compiler settings in both? Sounds like either the community version is a more recent update, or the warning settings are different.

[ai0376]

VS 2015 Community Vesion: 14.0.25420.01 Update 3 @gregmarr

[luomomo]

Hi ,I meet the problem in vs2015 :C2440，cannot convert from 'initializer-list' to nlohmann::basic_json ,is anyone know how to solve this?

[satyamsameer]

Hi Everyone,

I am trying this library by following all the steps as mentioned by including json.hpp in my project. Here I am also getting the same problem with the following error message.

error C4579: 'nlohmann::detail::static_constnlohmann::detail::from_json_fn::value': in-class initialization for type 'const T' is not yet implemented; static member will remain uninitialized at runtime but use in constant-expressions is supported

I am using vs 2015 Pro with Platform Toolset : Visual Studio 2015 (v140).
Anyone of you found any solution?

Thanks in advance

[ai0376]

Hi Everyone,

I am trying this library by following all the steps as mentioned by including json.hpp in my project. Here I am also getting the same problem with the following error message.

error C4579: 'nlohmann::detail::static_constnlohmann::detail::from_json_fn::value': in-class initialization for type 'const T' is not yet implemented; static member will remain uninitialized at runtime but use in constant-expressions is supported

I am using vs 2015 Pro with Platform Toolset : Visual Studio 2015 (v140).
Anyone of you found any solution?

Thanks in advance

use VS 2015 Community. or try vs2019 ?

[satyamsameer]

Thanks @mjrao for your reply. Actually in my organization we only have this version of VS subscription it will take time for them to upgrade this but because I need some solution urgently I have now used RapidJSON. I think this is because of old c++ compiler version. Will try this in latest VS as you mentioned I am sure it will work.