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) 1992-2018, 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
36package 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
116private
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
144end Ada.Command_Line;
145