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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: exc.c,v 1.6 2004/04/08 01:36:11 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 | |
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30 | #include <stdarg.h> |
31 | #include <stdlib.h> |
32 | #include <stdio.h> |
33 | |
34 | #include "exc.h" |
35 | |
36 | /*----- Global variables --------------------------------------------------*/ |
37 | |
38 | __exc_hnd *__exc_list = 0; |
39 | |
40 | /*----- Functions ---------------------------------------------------------*/ |
41 | |
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42 | /* --- @duff@ --- * |
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43 | * |
44 | * Arguments: @exc_extype type@ = type of duff exception |
45 | * @exc_exval val@ = extra data supplied |
46 | * |
47 | * Returns: Doesn't |
48 | * |
49 | * Use: Default handler when everything goes wrong. |
50 | */ |
51 | |
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52 | static void duff(exc_extype type, exc_exval val) |
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53 | { |
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54 | fprintf(stderr, "fatal error: uncaught exception (type = %lx)\n", type); |
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55 | abort(); |
56 | } |
57 | |
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58 | /* --- @duffproc@ --- * |
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59 | * |
60 | * Current handler when there are no more exceptions left. |
61 | */ |
62 | |
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63 | static exc__uncaught duffproc = duff; |
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64 | |
65 | /* --- @exc_uncaught@ --- * |
66 | * |
67 | * Arguments: @void (*proc)(exc_extype type, exc_exval val) = new handler |
68 | * |
69 | * Returns: Pointer to the old handler value. |
70 | * |
71 | * Use: Sets the handler for uncaught exceptions. |
72 | */ |
73 | |
74 | exc__uncaught exc_uncaught(exc__uncaught proc) |
75 | { |
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76 | exc__uncaught p = duffproc; |
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77 | if (proc) |
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78 | duffproc = proc; |
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79 | return (p); |
80 | } |
81 | |
82 | /* --- @__exc_throw@ --- * |
83 | * |
84 | * Arguments: @exc_extype type@ = type of exception to throw |
85 | * |
86 | * Returns: Doesn't |
87 | * |
88 | * Use: NOT FOR USER CONSUMPTION. Reads an appropriate exception |
89 | * value and throws an exception. |
90 | */ |
91 | |
92 | void __exc_throw(exc_extype type, ...) |
93 | { |
94 | va_list ap; |
95 | exc_exval v; |
96 | |
97 | va_start(ap, type); |
98 | switch (type & 0xC0) { |
99 | case EXC_NOVAL: |
100 | v.i = 0; |
101 | break; |
102 | case EXC_INTVAL: |
103 | v.i = va_arg(ap, int); |
104 | break; |
105 | case EXC_PTRVAL: |
106 | v.p = va_arg(ap, void *); |
107 | break; |
108 | case EXC_STRVAL: |
109 | v.s = va_arg(ap, char *); |
110 | break; |
111 | } |
112 | va_end(ap); |
113 | __exc_rethrow(type, v); |
114 | } |
115 | |
116 | /* --- @__exc_rethrow@ --- * |
117 | * |
118 | * Arguments: @exc_extype type@ = type of exception to throw |
119 | * @exc_exval val@ = value of exception to throw |
120 | * |
121 | * Returns: Doesn't |
122 | * |
123 | * Use: NOT FOR USER CONSUMPTION. Does the donkey-work of raising |
124 | * an exception. |
125 | */ |
126 | |
127 | void __exc_rethrow(exc_extype type, exc_exval val) |
128 | { |
129 | __exc_hnd *p = __exc_list; |
130 | if (!p) |
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131 | duffproc(type, val); |
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132 | p->type = type; |
133 | p->val = val; |
134 | __exc_list = p->next; |
135 | longjmp(p->buf, type); |
136 | } |
137 | |
138 | /*----- That's all, folks -------------------------------------------------*/ |