If u see my code,  I have used __int128 separately for the variable d as well. If u change the variant variable' s data type from __int128 to int , it will run just fine.

On Thu, 8 Apr 2021, 04:30 Edward Diener via Boost-users, <boost-users@lists.boost.org> wrote:
On 4/7/2021 3:38 PM, Anil Muthigi via Boost-users wrote:
> I said that I am not sure if boost::variant supports __int128 because I
> had difficulties in compiling this code :
>
>  1.
>     #include <boost/variant.hpp>
>  2.
>     #include <string>
>  3.
>     #include <iostream>
>  4.
>     std::ostream& operator<<(std::ostream& o, const __int128& x) { if (x
>     == std::numeric_limits<__int128>::min()) return o <<
>     "-170141183460469231731687303715884105728"; if (x < 0) return o <<
>     "-" << -x; if (x < 10) return o << (char)(x + '0'); return o << x /
>     10 << (char)(x % 10 + '0'); }
>  5.
>     int main()
>  6.
>     {
>  7.
>     boost::variant<__int128, char, std::string> v;
>  8.
>     v = 56;
>  9.
>     v = 'Y';
> 10.
>     __int128 d=12;
> 11.
>     std::cout <<d << '\n';
> 12.
>     std::cout << v << '\n';
> 13.
>     v = "Yashaswi raj";
> 14.
>     std::cout << v << '\n';
> 15.
>     }
>
> If u replace __int128 with int in the variant variable, it seems to work
> just fine...

My test with gcc-10.2 and clang-linux-11.0 shows that it does not
support __int128 in iostreams.

>
> On Thu, 8 Apr 2021, 00:10 Edward Diener via Boost-users,
> <boost-users@lists.boost.org <mailto:boost-users@lists.boost.org>> wrote:
>
>     On 4/7/2021 2:15 PM, Anil Muthigi via Boost-users wrote:
>      > I dont think so...
>
>     If it is available why do you think variant would not support it ?
>
>      > I guess int128_t under boost/multiprecision/cpp_int is the only
>     viable
>      > option.
>      >
>      > On Wed, 7 Apr 2021, 11:39 pm David Frank via Boost-users,
>      > <boost-users@lists.boost.org <mailto:boost-users@lists.boost.org>
>     <mailto:boost-users@lists.boost.org
>     <mailto:boost-users@lists.boost.org>>> wrote:
>      >
>      >     especially the gnu __int128?
>
>     _______________________________________________
>     Boost-users mailing list
>     Boost-users@lists.boost.org <mailto:Boost-users@lists.boost.org>
>     https://lists.boost.org/mailman/listinfo.cgi/boost-users
>     <https://lists.boost.org/mailman/listinfo.cgi/boost-users>
>
>
> _______________________________________________
> Boost-users mailing list
> Boost-users@lists.boost.org
> https://lists.boost.org/mailman/listinfo.cgi/boost-users
>


_______________________________________________
Boost-users mailing list
Boost-users@lists.boost.org
https://lists.boost.org/mailman/listinfo.cgi/boost-users