1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . V A L _ R E A L --
9 -- Copyright (C) 1992,1993,1994,1995,1996 Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 package System
.Val_Real
is
35 pragma Pure
(Val_Real
);
41 return Long_Long_Float;
42 -- This function scans the string starting at Str (Ptr.all) for a valid
43 -- real literal according to the syntax described in (RM 3.5(43)). The
44 -- substring scanned extends no further than Str (Max). There are three
45 -- cases for the return:
47 -- If a valid real is found after scanning past any initial spaces, then
48 -- Ptr.all is updated past the last character of the real (but trailing
49 -- spaces are not scanned out).
51 -- If no valid real is found, then Ptr.all points either to an initial
52 -- non-blank character, or to Max + 1 if the field is all spaces and the
53 -- exception Constraint_Error is raised.
55 -- If a syntactically valid real is scanned, but the value is out of
56 -- range, or, in the based case, the base value is out of range or there
57 -- is an out of range digit, then Ptr.all points past the real literal,
58 -- and Constraint_Error is raised.
60 -- Note: these rules correspond to the requirements for leaving the
61 -- pointer positioned in Text_Io.Get
63 -- Note: if Str is null, i.e. if Max is less than Ptr, then this is a
64 -- special case of an all-blank string, and Ptr is unchanged, and hence
65 -- is greater than Max as required in this case.
67 function Value_Real
(Str
: String) return Long_Long_Float;
68 -- Used in computing X'Value (Str) where X is a floating-point type or an
69 -- ordinary fixed-point type. Str is the string argument of the attribute.
70 -- Constraint_Error is raised if the string is malformed, or if the value
71 -- out of range of Long_Long_Float.