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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: exc.c,v 1.3 1999/05/06 19:51:35 mdw Exp $ |
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4 | * |
5 | * Structured exception handling in C |
6 | * |
7 | * (c) 1998 Straylight/Edgeware |
8 | */ |
9 | |
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10 | /*----- Licensing notice --------------------------------------------------* |
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11 | * |
12 | * This file is part of the mLib utilities library. |
13 | * |
14 | * mLib is free software; you can redistribute it and/or modify |
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15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
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19 | * mLib is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
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25 | * License along with mLib; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
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28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: exc.c,v $ |
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33 | * Revision 1.3 1999/05/06 19:51:35 mdw |
34 | * Reformatted the LGPL notice a little bit. |
35 | * |
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36 | * Revision 1.2 1999/05/05 18:50:31 mdw |
37 | * Change licensing conditions to LGPL. |
38 | * |
39 | * Revision 1.1.1.1 1998/06/17 23:44:42 mdw |
40 | * Initial version of mLib |
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41 | * |
42 | */ |
43 | |
44 | #include <stdarg.h> |
45 | #include <stdlib.h> |
46 | #include <stdio.h> |
47 | |
48 | #include "exc.h" |
49 | |
50 | /*----- Global variables --------------------------------------------------*/ |
51 | |
52 | __exc_hnd *__exc_list = 0; |
53 | |
54 | /*----- Functions ---------------------------------------------------------*/ |
55 | |
56 | /* --- @exc__duff@ --- * |
57 | * |
58 | * Arguments: @exc_extype type@ = type of duff exception |
59 | * @exc_exval val@ = extra data supplied |
60 | * |
61 | * Returns: Doesn't |
62 | * |
63 | * Use: Default handler when everything goes wrong. |
64 | */ |
65 | |
66 | static void exc__duff(exc_extype type, exc_exval val) |
67 | { |
68 | fprintf(stderr, "fatal error: uncaught exception (type = %lu)\n", type); |
69 | abort(); |
70 | } |
71 | |
72 | /* --- @exc__duffproc@ --- * |
73 | * |
74 | * Current handler when there are no more exceptions left. |
75 | */ |
76 | |
77 | static exc__uncaught exc__duffproc = exc__duff; |
78 | |
79 | /* --- @exc_uncaught@ --- * |
80 | * |
81 | * Arguments: @void (*proc)(exc_extype type, exc_exval val) = new handler |
82 | * |
83 | * Returns: Pointer to the old handler value. |
84 | * |
85 | * Use: Sets the handler for uncaught exceptions. |
86 | */ |
87 | |
88 | exc__uncaught exc_uncaught(exc__uncaught proc) |
89 | { |
90 | exc__uncaught p = exc__duffproc; |
91 | if (proc) |
92 | exc__duffproc = proc; |
93 | return (p); |
94 | } |
95 | |
96 | /* --- @__exc_throw@ --- * |
97 | * |
98 | * Arguments: @exc_extype type@ = type of exception to throw |
99 | * |
100 | * Returns: Doesn't |
101 | * |
102 | * Use: NOT FOR USER CONSUMPTION. Reads an appropriate exception |
103 | * value and throws an exception. |
104 | */ |
105 | |
106 | void __exc_throw(exc_extype type, ...) |
107 | { |
108 | va_list ap; |
109 | exc_exval v; |
110 | |
111 | va_start(ap, type); |
112 | switch (type & 0xC0) { |
113 | case EXC_NOVAL: |
114 | v.i = 0; |
115 | break; |
116 | case EXC_INTVAL: |
117 | v.i = va_arg(ap, int); |
118 | break; |
119 | case EXC_PTRVAL: |
120 | v.p = va_arg(ap, void *); |
121 | break; |
122 | case EXC_STRVAL: |
123 | v.s = va_arg(ap, char *); |
124 | break; |
125 | } |
126 | va_end(ap); |
127 | __exc_rethrow(type, v); |
128 | } |
129 | |
130 | /* --- @__exc_rethrow@ --- * |
131 | * |
132 | * Arguments: @exc_extype type@ = type of exception to throw |
133 | * @exc_exval val@ = value of exception to throw |
134 | * |
135 | * Returns: Doesn't |
136 | * |
137 | * Use: NOT FOR USER CONSUMPTION. Does the donkey-work of raising |
138 | * an exception. |
139 | */ |
140 | |
141 | void __exc_rethrow(exc_extype type, exc_exval val) |
142 | { |
143 | __exc_hnd *p = __exc_list; |
144 | if (!p) |
145 | exc__duffproc(type, val); |
146 | p->type = type; |
147 | p->val = val; |
148 | __exc_list = p->next; |
149 | longjmp(p->buf, type); |
150 | } |
151 | |
152 | /*----- That's all, folks -------------------------------------------------*/ |