File : 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) 1992-2013, 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 -- --
23 -- --
24 -- --
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 pragma Compiler_Unit_Warning;
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 -- Services in this package are not supported during the elaboration of an
77 -- auto-initialized Stand-Alone Library.
78
79 -- If the main program is in Ada, this package works as specified without
80 -- any other work than the normal steps of WITH'ing the package and then
81 -- calling the desired routines.
82
83 -- If the main program is not in Ada, then the information must be made
84 -- available for this package to work correctly. In particular, it is
85 -- required that the global variable "gnat_argc" contain the number of
86 -- arguments, and that the global variable "gnat_argv" points to an
87 -- array of null-terminated strings, the first entry being the command
88 -- name, and the remaining entries being the command arguments.
89
90 -- These correspond to the normal argc/argv variables passed to a C
91 -- main program, and the following is an example of a complete C main
92 -- program that stores the required information:
93
94 -- main(int argc, char **argv, char **envp)
95 -- {
96 -- extern int gnat_argc;
97 -- extern char **gnat_argv;
98 -- extern char **gnat_envp;
99 -- gnat_argc = argc;
100 -- gnat_argv = argv;
101 -- gnat_envp = envp;
102
103 -- adainit();
104 -- adamain();
105 -- adafinal();
106 -- }
107
108 -- The assignment statements ensure that the necessary information is
109 -- available for finding the command name and command line arguments.
110
111 private
112 Success : constant Exit_Status := 0;
113 Failure : constant Exit_Status := 1;
114
115 -- The following locations support the operation of the package
116 -- Ada.Command_Line.Remove, which provides facilities for logically
117 -- removing arguments from the command line. If one of the remove
118 -- procedures is called in this unit, then Remove_Args/Remove_Count
119 -- are set to indicate which arguments are removed. If no such calls
120 -- have been made, then Remove_Args is null.
121
122 Remove_Count : Natural;
123 -- Number of arguments reflecting removals. Not defined unless
124 -- Remove_Args is non-null.
125
126 type Arg_Nums is array (Positive range <>) of Positive;
127 type Arg_Nums_Ptr is access Arg_Nums;
128 -- An array that maps logical argument numbers (reflecting removal)
129 -- to physical argument numbers (e.g. if the first argument has been
130 -- removed, but not the second, then Arg_Nums (1) will be set to 2.
131
132 Remove_Args : Arg_Nums_Ptr := null;
133 -- Left set to null if no remove calls have been made, otherwise set
134 -- to point to an appropriate mapping array. Only the first Remove_Count
135 -- elements are relevant.
136
137 pragma Import (C, Set_Exit_Status, "__gnat_set_exit_status");
138
139 end Ada.Command_Line;