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[mLib] / exc.c
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0875b58f 1/* -*-c-*-
2 *
0bd98442 3 * $Id: exc.c,v 1.3 1999/05/06 19:51:35 mdw Exp $
0875b58f 4 *
5 * Structured exception handling in C
6 *
7 * (c) 1998 Straylight/Edgeware
8 */
9
c846879c 10/*----- Licensing notice --------------------------------------------------*
0875b58f 11 *
12 * This file is part of the mLib utilities library.
13 *
14 * mLib is free software; you can redistribute it and/or modify
c846879c 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 *
0875b58f 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
c846879c 22 * GNU Library General Public License for more details.
23 *
24 * You should have received a copy of the GNU Library General Public
0bd98442 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.
0875b58f 28 */
29
30/*----- Revision history --------------------------------------------------*
31 *
32 * $Log: exc.c,v $
0bd98442 33 * Revision 1.3 1999/05/06 19:51:35 mdw
34 * Reformatted the LGPL notice a little bit.
35 *
c846879c 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
0875b58f 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
66static 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
77static 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
88exc__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
106void __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
141void __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 -------------------------------------------------*/