File : s-exctra.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME COMPONENTS --
4 -- --
5 -- S Y S T E M . E X C E P T I O N _ T R A C E S --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 2000-2015, AdaCore --
10 -- --
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 3, 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. --
17 -- --
18 -- --
19 -- --
20 -- --
21 -- --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
26 -- --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
29 -- --
30 ------------------------------------------------------------------------------
31
32 -- This package provides an interface allowing to control *automatic* output
33 -- to standard error upon exception occurrences (as opposed to explicit
34 -- generation of traceback information using System.Traceback).
35
36 -- This output includes the basic information associated with the exception
37 -- (name, message) as well as a backtrace of the call chain at the point
38 -- where the exception occurred. This backtrace is only output if the call
39 -- chain information is available, depending if the binder switch dedicated
40 -- to that purpose has been used or not.
41
42 -- The default backtrace is in the form of absolute code locations which may
43 -- be converted to corresponding source locations using the addr2line utility
44 -- or from within GDB. Please refer to System.Traceback for information about
45 -- what is necessary to be able to exploit this possibility.
46
47 -- The backtrace output can also be customized by way of a "decorator" which
48 -- may return any string output in association with a provided call chain.
49 -- The decorator replaces the default backtrace mentioned above.
50
51 -- On systems that use DWARF debugging output, then if the "-g" compiler
52 -- switch and the "-Es" binder switch are used, the decorator is automatically
53 -- set to Symbolic_Traceback.
54
55 with System.Traceback_Entries;
56
57 package System.Exception_Traces is
58
59 -- The following defines the exact situations in which raises will
60 -- cause automatic output of trace information.
61
62 type Trace_Kind is
63 (Every_Raise,
64 -- Denotes the initial raise event for any exception occurrence, either
65 -- explicit or due to a specific language rule, within the context of a
66 -- task or not.
67
68 Unhandled_Raise,
69 -- Denotes the raise events corresponding to exceptions for which there
70 -- is no user defined handler. This includes unhandled exceptions in
71 -- task bodies.
72
73 Unhandled_Raise_In_Main
74 -- Same as Unhandled_Raise, except exceptions in task bodies are not
75 -- included.
76 );
77
78 -- The following procedures can be used to activate and deactivate
79 -- traces identified by the above trace kind values.
80
81 procedure Trace_On (Kind : Trace_Kind);
82 -- Activate the traces denoted by Kind
83
84 procedure Trace_Off;
85 -- Stop the tracing requested by the last call to Trace_On.
86 -- Has no effect if no such call has ever occurred.
87
88 -- The following provide the backtrace decorating facilities
89
90 type Traceback_Decorator is access
91 function (Traceback : Traceback_Entries.Tracebacks_Array) return String;
92 -- A backtrace decorator is a function which returns the string to be
93 -- output for a call chain provided by way of a tracebacks array.
94
95 procedure Set_Trace_Decorator (Decorator : Traceback_Decorator);
96 -- Set the decorator to be used for future automatic outputs. Restore the
97 -- default behavior if the provided access value is null.
98 --
99 -- Note: System.Traceback.Symbolic.Symbolic_Traceback may be used as the
100 -- Decorator, to get a symbolic traceback. This will cause a significant
101 -- cpu and memory overhead on some platforms.
102 --
103 -- Note: The Decorator is called when constructing the
104 -- Exception_Information; that needs to be taken into account
105 -- if the Decorator has any side effects.
106
107 end System.Exception_Traces;