gcc/testsuite/gnat.dg/unchecked_union3.adb

   1 --  { dg-do compile }
   2
   3 procedure Unchecked_Union3 is
   4    type small_array is array (0 .. 2) of Integer;
   5    type big_array   is array (0 .. 3) of Integer;
   6
   7    type small_record is record
   8       field1 : aliased Integer     := 0;
   9       field2 : aliased small_array := (0, 0, 0);
  10    end record;
  11
  12    type big_record is record
  13       field1 : aliased Integer   := 0;
  14       field2 : aliased big_array := (0, 0, 0, 0);
  15    end record;
  16
  17    type myUnion (discr : Integer := 0) is record
  18       case discr is
  19          when 0 =>
  20             record1 : aliased small_record;
  21          when others =>
  22             record2 : aliased big_record;
  23       end case;
  24    end record;
  25
  26    type UU_myUnion1 is new myUnion;
  27    pragma Unchecked_Union (UU_myUnion1);
  28    pragma Convention (C, UU_myUnion1);
  29
  30    procedure Convert (A : in myUnion; B : out UU_myUnion1) is
  31       L : UU_myUnion1 := UU_myUnion1 (A);  --  Test
  32    begin
  33       B := L;
  34    end Convert;
  35
  36 begin
  37    null;
  38 end Unchecked_Union3;