assigning a "float128" variable with a regular "double" variable

From: Jacques Mequin (j-mequin_at_[hidden])
Date: 2021-11-26 17:50:15

I am a fresh new user   ( I need to extend some EIGEN library feature by using your  float128 )

How to assign a "float128" variable with a regular "double" variable ?

With my source code in attachement

      double       double_pi =  3.141592653589793     ;
      float128  float128_pi =  3.141592653589793Q  ;

      produces the output that looks fine to me

      double_pi =
      3.141592653589793e+00

      float128_pi =
      3.141592653589793000000000000000000e+00

but  thestatement    float128_pi = double_pi ;    produces

      float128_pi =
      3.141592653589793115997963468544185e+00

How to get  3.141592653589793000000000000000000e+00 also from an assigment  ???

What am I doing wrong  ?

Thanks for any help

Regards,
    Jacques