gcc/ada/a-comlin.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                     A D A . C O M M A N D _ L I N E                      --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2005, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- This specification is derived from the Ada Reference Manual for use with --
  12 -- GNAT. The copyright notice above, and the license provisions that follow --
  13 -- apply solely to the  contents of the part following the private keyword. --
  14 --                                                                          --
  15 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  16 -- terms of the  GNU General Public License as published  by the Free Soft- --
  17 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  18 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  19 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  20 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  21 -- for  more details.  You should have  received  a copy of the GNU General --
  22 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  23 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  24 -- Boston, MA 02110-1301, USA.                                              --
  25 --                                                                          --
  26 -- As a special exception,  if other files  instantiate  generics from this --
  27 -- unit, or you link  this unit with other files  to produce an executable, --
  28 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  29 -- covered  by the  GNU  General  Public  License.  This exception does not --
  30 -- however invalidate  any other reasons why  the executable file  might be --
  31 -- covered by the  GNU Public License.                                      --
  32 --                                                                          --
  33 -- GNAT was originally developed  by the GNAT team at  New York University. --
  34 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  35 --                                                                          --
  36 ------------------------------------------------------------------------------
  37
  38 package Ada.Command_Line is
  39    pragma Preelaborate;
  40
  41    function Argument_Count return Natural;
  42    --  If the external execution environment supports passing arguments to a
  43    --  program, then Argument_Count returns the number of arguments passed to
  44    --  the program invoking the function. Otherwise it return 0.
  45    --
  46    --  In GNAT: Corresponds to (argc - 1) in C.
  47
  48    function Argument (Number : Positive) return String;
  49    --  If the external execution environment supports passing arguments to
  50    --  a program, then Argument returns an implementation-defined value
  51    --  corresponding to the argument at relative position Number. If Number
  52    --  is outside the range 1 .. Argument_Count, then Constraint_Error is
  53    --  propagated.
  54    --
  55    --  in GNAT: Corresponds to argv [n] (for n > 0) in C.
  56
  57    function Command_Name return String;
  58    --  If the external execution environment supports passing arguments to
  59    --  a program, then Command_Name returns an implementation-defined value
  60    --  corresponding to the name of the command invoking the program.
  61    --  Otherwise Command_Name returns the null string.
  62    --
  63    --  in GNAT: Corresponds to argv [0] in C.
  64
  65    type Exit_Status is new Integer;
  66
  67    Success : constant Exit_Status;
  68    Failure : constant Exit_Status;
  69
  70    procedure Set_Exit_Status (Code : Exit_Status);
  71
  72    ------------------------------------
  73    -- Note on Interface Requirements --
  74    ------------------------------------
  75
  76    --  If the main program is in Ada, this package works as specified without
  77    --  any other work than the normal steps of WITH'ing the package and then
  78    --  calling the desired routines.
  79
  80    --  If the main program is not in Ada, then the information must be made
  81    --  available for this package to work correctly. In particular, it is
  82    --  required that the global variable "gnat_argc" contain the number of
  83    --  arguments, and that the global variable "gnat_argv" points to an
  84    --  array of null-terminated strings, the first entry being the command
  85    --  name, and the remaining entries being the command arguments.
  86
  87    --  These correspond to the normal argc/argv variables passed to a C
  88    --  main program, and the following is an example of a complete C main
  89    --  program that stores the required information:
  90
  91    --    main(int argc, char **argv, char **envp)
  92    --    {
  93    --       extern int    gnat_argc;
  94    --       extern char **gnat_argv;
  95    --       extern char **gnat_envp;
  96    --       gnat_argc = argc;
  97    --       gnat_argv = argv;
  98    --       gnat_envp = envp;
  99
 100    --       adainit();
 101    --       adamain();
 102    --       adafinal();
 103    --    }
 104
 105    --  The assignment statements ensure that the necessary information is
 106    --  available for finding the command name and command line arguments.
 107
 108 private
 109    Success : constant Exit_Status := 0;
 110    Failure : constant Exit_Status := 1;
 111
 112    --  The following locations support the operation of the package
 113    --  Ada.Command_Line.Remove, whih provides facilities for logically
 114    --  removing arguments from the command line. If one of the remove
 115    --  procedures is called in this unit, then Remove_Args/Remove_Count
 116    --  are set to indicate which arguments are removed. If no such calls
 117    --  have been made, then Remove_Args is null.
 118
 119    Remove_Count : Natural;
 120    --  Number of arguments reflecting removals. Not defined unless
 121    --  Remove_Args is non-null.
 122
 123    type Arg_Nums is array (Positive range <>) of Positive;
 124    type Arg_Nums_Ptr is access Arg_Nums;
 125    --  An array that maps logical argument numbers (reflecting removal)
 126    --  to physical argument numbers (e.g. if the first argument has been
 127    --  removed, but not the second, then Arg_Nums (1) will be set to 2.
 128
 129    Remove_Args : Arg_Nums_Ptr := null;
 130    --  Left set to null if no remove calls have been made, otherwise set
 131    --  to point to an appropriate mapping array. Only the first Remove_Count
 132    --  elements are relevant.
 133
 134    pragma Import (C, Set_Exit_Status, "__gnat_set_exit_status");
 135
 136 end Ada.Command_Line;