On 4/7/2021 10:33 PM, Anil Muthigi via Boost-users wrote:
But I am not even doing any kind of input or output using __int128 FOR
THE VARIANT VARIABLE….
As you can see… if you choose to use int instead of __int128 for the
VARIANT VARIABLE and rerun the code…. it is actually printing the value
of the __int128 variable d which I have used in the code..
So, I guess it is actually picking up my std::ostream&
operator<<(std::ostream& o, const __int128& x) functionality.
I agree that variant does not support __int128. File a Issue report at
https://github.com/boostorg/variant if you wish. I am not the variant
maintainer. You may also try variant2.
On 08-Apr-2021, at 7:52 AM, Edward Diener via Boost-users
<boost-users@lists.boost.org <mailto:boost-users@lists.boost.org>> wrote:
On 4/7/2021 9:58 PM, Edward Diener via Boost-users wrote:
On 4/7/2021 7:10 PM, Anil Muthigi via Boost-users wrote:
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.
The reason your code is failing is because your stream operator uses
streaming and __int128 has no stream support. If you use an __int128
in a variant, but never use streaming, your code is fine. I do not
know the reason why gcc and clang support __int128 but do not support
the the type in streaming. Maybe you should try asking gcc about it
or investigate it as a stackoverflow question.
Please do not topmost.
Apologies ! It looks as if the variant i/o is simply not picking up
your std::ostream& operator<<(std::ostream& o, const __int128& x)
functionality. I tried putting your functionality in namespace boost
but it still did not pick it up.
On Thu, 8 Apr 2021, 04:30 Edward Diener 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:
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.
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