Ada. Time-tested, safe and secure.

This language feature is available from Ada 95 on. Ada.Numerics is a unit of the Predefined Language Environment since Ada 95.

Specification

package Ada.Numerics is
   pragma Pure (Numerics);
   Argument_Error : exception;
   Pi : constant :=
         3.14159_26535_89793_23846_26433_83279_50288_41971_69399_37511;
   π  : constant := Pi;
   e  : constant :=
         2.71828_18284_59045_23536_02874_71352_66249_77572_47093_69996;
end Ada.Numerics;

π 

This language feature is only available from Ada 2005 on.

See also