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:
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
On 4/7/2021 7:10 PM, Anil Muthigi via Boost-users wrote: 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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