gcc/ada/libgnat/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) 1992-2017, 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 3,  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.                                     --
  21 --                                                                          --
  22 -- As a special exception under Section 7 of GPL version 3, you are granted --
  23 -- additional permissions described in the GCC Runtime Library Exception,   --
  24 -- version 3.1, as published by the Free Software Foundation.               --
  25 --                                                                          --
  26 -- You should have received a copy of the GNU General Public License and    --
  27 -- a copy of the GCC Runtime Library Exception along with this program;     --
  28 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  29 -- <http://www.gnu.org/licenses/>.                                          --
  30 --                                                                          --
  31 -- GNAT was originally developed  by the GNAT team at  New York University. --
  32 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 package Ada.Command_Line is
  37    pragma Preelaborate;
  38
  39    function Argument_Count return Natural;
  40    --  If the external execution environment supports passing arguments to a
  41    --  program, then Argument_Count returns the number of arguments passed to
  42    --  the program invoking the function. Otherwise it return 0.
  43    --
  44    --  In GNAT: Corresponds to (argc - 1) in C.
  45
  46    pragma Assertion_Policy (Pre => Ignore);
  47    --  We need to ignore the precondition of Argument, below, so that we don't
  48    --  raise Assertion_Error. The body raises Constraint_Error. It would be
  49    --  cleaner to add "or else raise Constraint_Error" to the precondition, but
  50    --  SPARK does not yet support raise expressions.
  51
  52    function Argument (Number : Positive) return String with
  53       Pre => Number <= Argument_Count;
  54    --  If the external execution environment supports passing arguments to
  55    --  a program, then Argument returns an implementation-defined value
  56    --  corresponding to the argument at relative position Number. If Number
  57    --  is outside the range 1 .. Argument_Count, then Constraint_Error is
  58    --  propagated.
  59    --
  60    --  in GNAT: Corresponds to argv [n] (for n > 0) in C.
  61
  62    function Command_Name return String;
  63    --  If the external execution environment supports passing arguments to
  64    --  a program, then Command_Name returns an implementation-defined value
  65    --  corresponding to the name of the command invoking the program.
  66    --  Otherwise Command_Name returns the null string.
  67    --
  68    --  in GNAT: Corresponds to argv [0] in C.
  69
  70    type Exit_Status is new Integer;
  71
  72    Success : constant Exit_Status;
  73    Failure : constant Exit_Status;
  74
  75    procedure Set_Exit_Status (Code : Exit_Status);
  76
  77    ------------------------------------
  78    -- Note on Interface Requirements --
  79    ------------------------------------
  80
  81    --  Services in this package are not supported during the elaboration of an
  82    --  auto-initialized Stand-Alone Library.
  83
  84    --  If the main program is in Ada, this package works as specified without
  85    --  any other work than the normal steps of WITH'ing the package and then
  86    --  calling the desired routines.
  87
  88    --  If the main program is not in Ada, then the information must be made
  89    --  available for this package to work correctly. In particular, it is
  90    --  required that the global variable "gnat_argc" contain the number of
  91    --  arguments, and that the global variable "gnat_argv" points to an
  92    --  array of null-terminated strings, the first entry being the command
  93    --  name, and the remaining entries being the command arguments.
  94
  95    --  These correspond to the normal argc/argv variables passed to a C
  96    --  main program, and the following is an example of a complete C main
  97    --  program that stores the required information:
  98
  99    --    main(int argc, char **argv, char **envp)
 100    --    {
 101    --       extern int    gnat_argc;
 102    --       extern char **gnat_argv;
 103    --       extern char **gnat_envp;
 104    --       gnat_argc = argc;
 105    --       gnat_argv = argv;
 106    --       gnat_envp = envp;
 107
 108    --       adainit();
 109    --       adamain();
 110    --       adafinal();
 111    --    }
 112
 113    --  The assignment statements ensure that the necessary information is
 114    --  available for finding the command name and command line arguments.
 115
 116 private
 117    Success : constant Exit_Status := 0;
 118    Failure : constant Exit_Status := 1;
 119
 120    --  The following locations support the operation of the package
 121    --  Ada.Command_Line.Remove, which provides facilities for logically
 122    --  removing arguments from the command line. If one of the remove
 123    --  procedures is called in this unit, then Remove_Args/Remove_Count
 124    --  are set to indicate which arguments are removed. If no such calls
 125    --  have been made, then Remove_Args is null.
 126
 127    Remove_Count : Natural;
 128    --  Number of arguments reflecting removals. Not defined unless
 129    --  Remove_Args is non-null.
 130
 131    type Arg_Nums is array (Positive range <>) of Positive;
 132    type Arg_Nums_Ptr is access Arg_Nums;
 133    --  An array that maps logical argument numbers (reflecting removal)
 134    --  to physical argument numbers (e.g. if the first argument has been
 135    --  removed, but not the second, then Arg_Nums (1) will be set to 2.
 136
 137    Remove_Args : Arg_Nums_Ptr := null;
 138    --  Left set to null if no remove calls have been made, otherwise set
 139    --  to point to an appropriate mapping array. Only the first Remove_Count
 140    --  elements are relevant.
 141
 142    pragma Import (C, Set_Exit_Status, "__gnat_set_exit_status");
 143
 144 end Ada.Command_Line;