Roadmap to c++14 support?

hey guys, I was wondering if c++14 support is avaiable somehow through the root interpreter, an if not, is there is any expected release date for it?
thanks
d4nf

C++14 is fully supported in the interpreter and is automatically enabled if you build ROOT (or cling) in c++14 mode.

Cheers,
Philippe.

hey philippe,
thanks for letting me know about the flag,

unfortunately i tried to compile root 6.08.02 with the cxx14 option enabled (gcc 6.2.0 on linux), and the build fails to compile somewhere at graf2d.

I couldn’t figure out how to post bugs/issues on JIRA, so ill resort to posting it here

[ 63%] Building CXX object graf2d/gpad/CMakeFiles/Gpad.dir/v7/src/TCanvas.cxx.o
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RWrap_libcpp_string_view.h:520:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:26,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:41,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TNamed.h:29,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualX.h:31,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualPad.h:30,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TPad.h:17,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TCanvas.h:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:19:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/libcpp_string_view.h:786:89: error: template argument 1 is invalid
 struct _LIBCPP_TYPE_VIS_ONLY hash<std::experimental::basic_string_view<_CharT, _Traits> >
                                                                                         ^
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/libcpp_string_view.h:787:90: error: wrong number of template arguments (1, should be 2)
     : public unary_function<std::experimental::basic_string_view<_CharT, _Traits>, size_t>
                                                                                          ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:48:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/stl_function.h:105:12: note: provided for ‘template<class _Arg, class _Result> struct std::unary_function’
     struct unary_function
            ^~~~~~~~~~~~~~
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RWrap_libcpp_string_view.h:520:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:26,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:41,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TNamed.h:29,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualX.h:31,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualPad.h:30,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TPad.h:17,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TCanvas.h:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:19:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/libcpp_string_view.h:794:60: error: template argument 1 is invalid
 hash<std::experimental::basic_string_view<_CharT, _Traits> >::operator()(
                                                            ^
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/libcpp_string_view.h:795:15: error: reference to ‘basic_string_view’ is ambiguous
         const std::experimental::basic_string_view<_CharT, _Traits>& __val) const _NOEXCEPT
               ^~~
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:75:11: note: candidates are: template<class _CharT, class _Traits> class std::experimental::fundamentals_v1::basic_string_view
     class basic_string_view
           ^~~~~~~~~~~~~~~~~
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RWrap_libcpp_string_view.h:520:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:26,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:41,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TNamed.h:29,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualX.h:31,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualPad.h:30,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TPad.h:17,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TCanvas.h:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:19:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/libcpp_string_view.h:195:33: note:                 template<class _CharT, class _Traits> class std::experimental::__ROOT::basic_string_view
     class _LIBCPP_TYPE_VIS_ONLY basic_string_view {
                                 ^~~~~~~~~~~~~~~~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/libcpp_string_view.h:795:51: error: expected ‘,’ or ‘...’ before ‘<’ token
         const std::experimental::basic_string_view<_CharT, _Traits>& __val) const _NOEXCEPT
                                                   ^
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/libcpp_string_view.h:795:77: error: non-member function ‘std::size_t std::operator()(int)’ cannot have cv-qualifier
         const std::experimental::basic_string_view<_CharT, _Traits>& __val) const _NOEXCEPT
                                                                             ^~~~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/libcpp_string_view.h:795:77: error: ‘std::size_t std::operator()(int)’ must be a nonstatic member function
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:41:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TNamed.h:29,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualX.h:31,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualPad.h:30,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TPad.h:17,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TCanvas.h:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:19:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:32:30: error: reference to ‘basic_string_view’ is ambiguous
    using basic_string_view = ::std::experimental::basic_string_view<_CharT,_Traits>;
                              ^~
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:75:11: note: candidates are: template<class _CharT, class _Traits> class std::experimental::fundamentals_v1::basic_string_view
     class basic_string_view
           ^~~~~~~~~~~~~~~~~
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RWrap_libcpp_string_view.h:520:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:26,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:41,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TNamed.h:29,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualX.h:31,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualPad.h:30,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TPad.h:17,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TCanvas.h:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:19:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/libcpp_string_view.h:195:33: note:                 template<class _CharT, class _Traits> class std::experimental::__ROOT::basic_string_view
     class _LIBCPP_TYPE_VIS_ONLY basic_string_view {
                                 ^~~~~~~~~~~~~~~~~
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:41:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TNamed.h:29,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualX.h:31,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualPad.h:30,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TPad.h:17,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TCanvas.h:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:19:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:35:12: error: ‘basic_string_view’ does not name a type
    typedef basic_string_view<char> string_view;
            ^~~~~~~~~~~~~~~~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:36:12: error: ‘basic_string_view’ does not name a type
    typedef basic_string_view<char16_t> u16string_view;
            ^~~~~~~~~~~~~~~~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:37:12: error: ‘basic_string_view’ does not name a type
    typedef basic_string_view<char32_t> u32string_view;
            ^~~~~~~~~~~~~~~~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:38:12: error: ‘basic_string_view’ does not name a type
    typedef basic_string_view<wchar_t> wstring_view;
            ^~~~~~~~~~~~~~~~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:48:28: error: ‘std::stod’ declared as an ‘inline’ variable
    inline double stod(std::string_view str, size_t *pos)
                            ^~~~~~~~~~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:48:23: error: ‘string_view’ is not a member of ‘std’
    inline double stod(std::string_view str, size_t *pos)
                       ^~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:48:23: note: suggested alternatives:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:48:28: note:   ‘#‘tree_list’ not supported by dump_expr#<expression error>’
    inline double stod(std::string_view str, size_t *pos)
                            ^~~~~~~~~~~
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:572:46: note:   ‘std::experimental::fundamentals_v1::string_view’
   using string_view = basic_string_view<char>;
                                              ^
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RWrap_libcpp_string_view.h:520:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:26,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:41,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TNamed.h:29,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualX.h:31,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualPad.h:30,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TPad.h:17,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TCanvas.h:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:19:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/libcpp_string_view.h:775:39: note:   ‘std::experimental::__ROOT::string_view’
   typedef basic_string_view<char>     string_view;
                                       ^~~~~~~~~~~
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:41:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TNamed.h:29,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualX.h:31,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualPad.h:30,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TPad.h:17,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TCanvas.h:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:19:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:48:52: error: expected primary-expression before ‘*’ token
    inline double stod(std::string_view str, size_t *pos)
                                                    ^
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:48:53: error: ‘pos’ was not declared in this scope
    inline double stod(std::string_view str, size_t *pos)
                                                     ^~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:48:56: error: expression list treated as compound expression in initializer [-fpermissive]
    inline double stod(std::string_view str, size_t *pos)
                                                        ^
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TNamed.h:29:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualX.h:31,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualPad.h:30,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TPad.h:17,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TCanvas.h:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:19:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:116:13: error: expected type-specifier
    operator std::string_view() const { return std::string_view(Data(),fExtent); }
             ^~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h: In member function ‘TSubString::operator std::__cxx11::string() const’:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:117:42: error: ‘string_view’ is not a member of ‘std’
    operator std::string() const { return std::string_view(Data(),fExtent).to_string(); }
                                          ^~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:117:42: note: suggested alternatives:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:117:47: note:   ‘#‘tree_list’ not supported by dump_expr#<expression error>’
    operator std::string() const { return std::string_view(Data(),fExtent).to_string(); }
                                               ^~~~~~~~~~~
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:572:46: note:   ‘std::experimental::fundamentals_v1::string_view’
   using string_view = basic_string_view<char>;
                                              ^
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RWrap_libcpp_string_view.h:520:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/RStringView.h:26,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:41,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TNamed.h:29,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualX.h:31,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualPad.h:30,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TPad.h:17,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TCanvas.h:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:19:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/libcpp_string_view.h:775:39: note:   ‘std::experimental::__ROOT::string_view’
   typedef basic_string_view<char>     string_view;
                                       ^~~~~~~~~~~
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TNamed.h:29:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualX.h:31,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualPad.h:30,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TPad.h:17,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TCanvas.h:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:19:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h: At global scope:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:269:23: error: ‘string_view’ in namespace ‘std’ does not name a type
    TString(const std::string_view &sub);
                       ^~~~~~~~~~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:290:13: error: expected type-specifier
    operator std::string_view() const { return std::string_view(GetPointer(),Length()); }
             ^~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:297:37: error: ‘string_view’ in namespace ‘std’ does not name a type
    TString    &operator=(const std::string_view &s);
                                     ^~~~~~~~~~~
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TNamed.h:29:0,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualX.h:31,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TVirtualPad.h:30,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TPad.h:17,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TCanvas.h:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:19:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/TString.h:787:37: error: ‘string_view’ in namespace ‘std’ does not name a type
   std::string printValue(const std::string_view* val);
                                     ^~~~~~~~~~~
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:22:0:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:96:37: error: ‘std::string_view’ has not been declared
     TLogEntry(ELogLevel level, std::string_view group):
                                     ^~~~~~~~~~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:98:37: error: ‘std::string_view’ has not been declared
     TLogEntry(ELogLevel level, std::string_view group, std::string_view filename,
                                     ^~~~~~~~~~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:98:61: error: ‘std::string_view’ has not been declared
     TLogEntry(ELogLevel level, std::string_view group, std::string_view filename,
                                                             ^~~~~~~~~~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:99:27: error: ‘std::string_view’ has not been declared
            int line, std::string_view funcname):
                           ^~~~~~~~~~~
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx: In constructor ‘ROOT::Experimental::TLogEntry::TLogEntry(ROOT::Experimental::ELogLevel, int)’:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:97:35: error: no matching function for call to ‘std::__cxx11::basic_string<char>::basic_string(int&)’
        fGroup(group), fLevel(level) {}
                                   ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:52:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:549:9: note: candidate: template<class _InputIterator, class> std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(_InputIterator, _InputIterator, const _Alloc&)
         basic_string(_InputIterator __beg, _InputIterator __end,
         ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:549:9: note:   template argument deduction/substitution failed:
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:22:0:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:97:35: note:   candidate expects 3 arguments, 1 provided
        fGroup(group), fLevel(level) {}
                                   ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:52:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:511:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&&, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(basic_string&& __str, const _Alloc& __a)
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:511:7: note:   candidate expects 2 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:507:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(const basic_string& __str, const _Alloc& __a)
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:507:7: note:   candidate expects 2 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:503:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::initializer_list<_Tp>, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc())
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:503:7: note:   no known conversion for argument 1 from ‘int’ to ‘std::initializer_list<char>’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:476:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(basic_string&& __str) noexcept
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:476:7: note:   no known conversion for argument 1 from ‘int’ to ‘std::__cxx11::basic_string<char>&&’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:464:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, _CharT, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc())
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:464:7: note:   candidate expects 3 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:454:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>] <near match>
       basic_string(const _CharT* __s, const _Alloc& __a = _Alloc())
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:454:7: note:   conversion of argument 1 would be ill-formed:
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:22:0:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:97:35: error: invalid conversion from ‘int’ to ‘const char*’ [-fpermissive]
        fGroup(group), fLevel(level) {}
                                   ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:52:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:444:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(const _CharT* __s, size_type __n,
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:444:7: note:   candidate expects 3 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:426:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(const basic_string& __str, size_type __pos,
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:426:7: note:   candidate expects 4 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:410:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(const basic_string& __str, size_type __pos,
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:410:7: note:   candidate expects 3 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:397:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(const basic_string& __str)
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:397:7: note:   no known conversion for argument 1 from ‘int’ to ‘const std::__cxx11::basic_string<char>&’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:389:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(const _Alloc& __a) _GLIBCXX_NOEXCEPT
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:389:7: note:   no known conversion for argument 1 from ‘int’ to ‘const std::allocator<char>&’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:380:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string() [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string()
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:380:7: note:   candidate expects 0 arguments, 1 provided
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:22:0:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx: In constructor ‘ROOT::Experimental::TLogEntry::TLogEntry(ROOT::Experimental::ELogLevel, int, int, int, int)’:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:101:17: error: no matching function for call to ‘std::__cxx11::basic_string<char>::basic_string(int&)’
     fLevel(level) {}
                 ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:52:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:549:9: note: candidate: template<class _InputIterator, class> std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(_InputIterator, _InputIterator, const _Alloc&)
         basic_string(_InputIterator __beg, _InputIterator __end,
         ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:549:9: note:   template argument deduction/substitution failed:
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:22:0:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:101:17: note:   candidate expects 3 arguments, 1 provided
     fLevel(level) {}
                 ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:52:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:511:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&&, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(basic_string&& __str, const _Alloc& __a)
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:511:7: note:   candidate expects 2 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:507:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(const basic_string& __str, const _Alloc& __a)
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:507:7: note:   candidate expects 2 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:503:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::initializer_list<_Tp>, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc())
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:503:7: note:   no known conversion for argument 1 from ‘int’ to ‘std::initializer_list<char>’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:476:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(basic_string&& __str) noexcept
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:476:7: note:   no known conversion for argument 1 from ‘int’ to ‘std::__cxx11::basic_string<char>&&’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:464:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, _CharT, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc())
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:464:7: note:   candidate expects 3 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:454:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>] <near match>
       basic_string(const _CharT* __s, const _Alloc& __a = _Alloc())
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:454:7: note:   conversion of argument 1 would be ill-formed:
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:22:0:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:101:17: error: invalid conversion from ‘int’ to ‘const char*’ [-fpermissive]
     fLevel(level) {}
                 ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:52:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:444:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(const _CharT* __s, size_type __n,
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:444:7: note:   candidate expects 3 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:426:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(const basic_string& __str, size_type __pos,
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:426:7: note:   candidate expects 4 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:410:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(const basic_string& __str, size_type __pos,
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:410:7: note:   candidate expects 3 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:397:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(const basic_string& __str)
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:397:7: note:   no known conversion for argument 1 from ‘int’ to ‘const std::__cxx11::basic_string<char>&’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:389:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(const _Alloc& __a) _GLIBCXX_NOEXCEPT
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:389:7: note:   no known conversion for argument 1 from ‘int’ to ‘const std::allocator<char>&’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:380:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string() [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string()
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:380:7: note:   candidate expects 0 arguments, 1 provided
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:22:0:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:101:17: error: no matching function for call to ‘std::__cxx11::basic_string<char>::basic_string(int&)’
     fLevel(level) {}
                 ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:52:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:549:9: note: candidate: template<class _InputIterator, class> std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(_InputIterator, _InputIterator, const _Alloc&)
         basic_string(_InputIterator __beg, _InputIterator __end,
         ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:549:9: note:   template argument deduction/substitution failed:
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:22:0:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:101:17: note:   candidate expects 3 arguments, 1 provided
     fLevel(level) {}
                 ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:52:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:511:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&&, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(basic_string&& __str, const _Alloc& __a)
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:511:7: note:   candidate expects 2 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:507:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(const basic_string& __str, const _Alloc& __a)
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:507:7: note:   candidate expects 2 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:503:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::initializer_list<_Tp>, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc())
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:503:7: note:   no known conversion for argument 1 from ‘int’ to ‘std::initializer_list<char>’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:476:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(basic_string&& __str) noexcept
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:476:7: note:   no known conversion for argument 1 from ‘int’ to ‘std::__cxx11::basic_string<char>&&’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:464:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, _CharT, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc())
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:464:7: note:   candidate expects 3 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:454:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>] <near match>
       basic_string(const _CharT* __s, const _Alloc& __a = _Alloc())
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:454:7: note:   conversion of argument 1 would be ill-formed:
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:22:0:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:101:17: error: invalid conversion from ‘int’ to ‘const char*’ [-fpermissive]
     fLevel(level) {}
                 ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:52:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:444:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(const _CharT* __s, size_type __n,
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:444:7: note:   candidate expects 3 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:426:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(const basic_string& __str, size_type __pos,
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:426:7: note:   candidate expects 4 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:410:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(const basic_string& __str, size_type __pos,
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:410:7: note:   candidate expects 3 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:397:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(const basic_string& __str)
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:397:7: note:   no known conversion for argument 1 from ‘int’ to ‘const std::__cxx11::basic_string<char>&’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:389:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(const _Alloc& __a) _GLIBCXX_NOEXCEPT
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:389:7: note:   no known conversion for argument 1 from ‘int’ to ‘const std::allocator<char>&’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:380:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string() [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string()
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:380:7: note:   candidate expects 0 arguments, 1 provided
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:22:0:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:101:17: error: no matching function for call to ‘std::__cxx11::basic_string<char>::basic_string(int&)’
     fLevel(level) {}
                 ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:52:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:549:9: note: candidate: template<class _InputIterator, class> std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(_InputIterator, _InputIterator, const _Alloc&)
         basic_string(_InputIterator __beg, _InputIterator __end,
         ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:549:9: note:   template argument deduction/substitution failed:
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:22:0:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:101:17: note:   candidate expects 3 arguments, 1 provided
     fLevel(level) {}
                 ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:52:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:511:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&&, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(basic_string&& __str, const _Alloc& __a)
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:511:7: note:   candidate expects 2 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:507:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(const basic_string& __str, const _Alloc& __a)
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:507:7: note:   candidate expects 2 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:503:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::initializer_list<_Tp>, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc())
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:503:7: note:   no known conversion for argument 1 from ‘int’ to ‘std::initializer_list<char>’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:476:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]
       basic_string(basic_string&& __str) noexcept
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:476:7: note:   no known conversion for argument 1 from ‘int’ to ‘std::__cxx11::basic_string<char>&&’
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:464:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, _CharT, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc())
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:464:7: note:   candidate expects 3 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:454:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>] <near match>
       basic_string(const _CharT* __s, const _Alloc& __a = _Alloc())
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:454:7: note:   conversion of argument 1 would be ill-formed:
In file included from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:22:0:
/home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TLogger.hxx:101:17: error: invalid conversion from ‘int’ to ‘const char*’ [-fpermissive]
     fLevel(level) {}
                 ^
In file included from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/string:52:0,
                 from /home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/experimental/string_view:42,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/rbuild/include/ROOT/TCanvas.hxx:18,
                 from /home/d4nf/Custom_Libs/Root-CERN/root-6.08.02/graf2d/gpad/v7/src/TCanvas.cxx:16:
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:444:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(const _CharT* __s, size_type __n,
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:444:7: note:   candidate expects 3 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:426:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, const _Alloc&) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(const basic_string& __str, size_type __pos,
       ^~~~~~~~~~~~
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:426:7: note:   candidate expects 4 arguments, 1 provided
/home/d4nf/Custom_Libs/gcc620/include/c++/6.2.0/bits/basic_string.h:410:7: note: candidate: std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::basic_string(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type = long unsigned int]
       basic_string(const basic_string& __str, size_type __pos,
       ....

[quote]unfortunately i tried to compile root 6.08.02 with the cxx14 option enabled (gcc 6.2.0 on linux), and the build fails to compile somewhere at graf2d.
[/quote]You must start the configuration and compilation from a fresh build directory. ‘Just’ switching a build from C++11 to C++14 does not (yet?) properly recalculated some of the configuration variable and ends up still using code that should only be used in C++11 mode.

Cheers,
Philippe.

In rbuild (nothing built at the time) i was calling
cmake …
Then
ccmake .
Before i built anything. Im not at a machine right now, but ikl try to run ccmake from a brand new dir again… i don’t think it’s going to work, but i’ll let you know how it goes

Doing a new dir with cmake … -Dcxx14=ON
Worked.

Thanks!