Question

我正在尝试使用Calculator.ada编译此gcc -c Calculator.ada文件并收到错误warning: Calculator.ada: linker input file unused because linking not done - 我尝试查找解决方案并下载其他可能为我编译的内容但还没想出来......

以下是Calculator.ada：

--
-- Integer calculator program.  Takes lines of input consisting of
-- <operator> <number>, and applies each one to a display value.  The
-- display value is printed at each step.  The operator is one of =,
-- +, -, *, /, or ^, which correspond to assign, add, subtract, multiply
-- divide, and raise, respectively.  The display value is initially zero.
-- The program terminates on a input of q.
--
with Text_IO;
with Gnat.Io; use Gnat.Io;
procedure Calc is
   Op: Character;               -- Operation to perform.
   Disp: Integer := 0;          -- Contents of the display.
   In_Val: Integer;             -- Input value used to update the display.
begin
   loop
      -- Print the display.
      Put(Disp);
      New_Line;

      -- Promt the user.
      Put("> ");

      -- Skip leading blanks and read the operation.
      loop
         Get(Op);
         exit when Op /= ' ';
      end loop;

      -- Stop when we're s'posed to.
      exit when Op = 'Q' or Op = 'q';

      -- Read the integer value (skips leading blanks) and discard the
      -- remainder of the line.
      Get(In_Val);
      Text_IO.Skip_Line;

      -- Apply the correct operation.
      case Op is
         when '='      => Disp := In_Val;
         when '+'      => Disp := Disp + In_Val;
         when '-'      => Disp := Disp - In_Val;
         when '*'      => Disp := Disp * In_Val;
         when '/'      => Disp := Disp / In_Val;
         when '^'      => Disp := Disp ** In_Val;
         when '0'..'9' => Put_Line("Please specify an operation.");
         when others   => Put_Line("What is " & Op & "?");
      end case;
   end loop;
end Calc;

我将不胜感激为什么我无法编译这个。我可以使用gcc -c编译C文件并阅读我可以为Ada编译相同的方法。

Answer 1

由于gcc仅识别.ads和.adb作为Ada源的文件结尾（如Eugene提到的here中所述），因此您需要明确告诉它您希望此文件为编译为Ada源。你可以通过

来做到这一点

gcc -x ada -c Calculator.ada

编译器可能会发出类似

的警告

Calculator.ada:11:11: warning: file name does not match unit name, should be "calc.adb"

但你可以忽略它。但是，最佳做法是使用gcc预期的文件名。

Answer 2

默认情况下，Ada源文件需要以.ads（对于包规范）或.adb（对于实体）结束，文件名需要与它们包含的顶级实体匹配。在您的情况下，您应该使用calc.adb。

如果您有更复杂的源文件包含多个实体，则可以使用gnatchop tool to rename source files。

在File Naming Topics and Utilities下，本手册包含更多文档，说明如何在文件系统中表示源代码。

Ada - 用GCC编译Ada

2 个答案: