Re: does boost::variant support 128 bit integer?

From: Anil Muthigi (anilmuthigi123_at_[hidden])
Date: 2021-04-07 23:10:21

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_at_[hidden]> 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_at_[hidden] <mailto:boost-users_at_[hidden]>>
> 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_at_[hidden] <mailto:boost-users_at_[hidden]>
> >     <mailto:boost-users_at_[hidden]
> >     <mailto:boost-users_at_[hidden]>>> wrote:
> >      >
> >      >     especially the gnu __int128?
> >
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