[mLib] / exc.c

/* -*-c-*-
 *
 * $Id: exc.c,v 1.1 1998/06/17 23:44:42 mdw Exp $
 *
 * Structured exception handling in C
 *
 * (c) 1998 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of the mLib utilities library.
 *
 * mLib is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * mLib is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with mLib; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------*
 *
 * $Log: exc.c,v $
 * Revision 1.1  1998/06/17 23:44:42  mdw
 * Initial revision
 *
 */

#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>

#include "exc.h"

/*----- Global variables --------------------------------------------------*/

__exc_hnd *__exc_list = 0;

/*----- Functions ---------------------------------------------------------*/

/* --- @exc__duff@ --- *
 *
 * Arguments:	@exc_extype type@ = type of duff exception
 *		@exc_exval val@ = extra data supplied
 *
 * Returns:	Doesn't
 *
 * Use:		Default handler when everything goes wrong.
 */

static void exc__duff(exc_extype type, exc_exval val)
{
  fprintf(stderr, "fatal error: uncaught exception (type = %lu)\n", type);
  abort();
}

/* --- @exc__duffproc@ --- *
 *
 * Current handler when there are no more exceptions left.
 */

static exc__uncaught exc__duffproc = exc__duff;

/* --- @exc_uncaught@ --- *
 *
 * Arguments:	@void (*proc)(exc_extype type, exc_exval val) = new handler
 *
 * Returns:	Pointer to the old handler value.
 *
 * Use:		Sets the handler for uncaught exceptions.
 */

exc__uncaught exc_uncaught(exc__uncaught proc)
{
  exc__uncaught p = exc__duffproc;
  if (proc)
    exc__duffproc = proc;
  return (p);
}

/* --- @__exc_throw@ --- *
 *
 * Arguments:	@exc_extype type@ = type of exception to throw
 *
 * Returns:	Doesn't
 *
 * Use:		NOT FOR USER CONSUMPTION.  Reads an appropriate exception
 *		value and throws an exception.
 */

void __exc_throw(exc_extype type, ...)
{
  va_list ap;
  exc_exval v;

  va_start(ap, type);
  switch (type & 0xC0) {
    case EXC_NOVAL:
      v.i = 0;
      break;
    case EXC_INTVAL:
      v.i = va_arg(ap, int);
      break;
    case EXC_PTRVAL:
      v.p = va_arg(ap, void *);
      break;
    case EXC_STRVAL:
      v.s = va_arg(ap, char *);
      break;
  }
  va_end(ap);
  __exc_rethrow(type, v);
}

/* --- @__exc_rethrow@ --- *
 *
 * Arguments:	@exc_extype type@ = type of exception to throw
 *		@exc_exval val@ = value of exception to throw
 *
 * Returns:	Doesn't
 *
 * Use:		NOT FOR USER CONSUMPTION.  Does the donkey-work of raising
 *		an exception.
 */

void __exc_rethrow(exc_extype type, exc_exval val)
{
  __exc_hnd *p = __exc_list;
  if (!p)
    exc__duffproc(type, val);
  p->type = type;
  p->val = val;
  __exc_list = p->next;
  longjmp(p->buf, type);
}  

/*----- That's all, folks -------------------------------------------------*/
Commit	Line	Data
0875b58f	1	/* --c--
	2	*
	3	* $Id: exc.c,v 1.1 1998/06/17 23:44:42 mdw Exp $
	4	*
	5	* Structured exception handling in C
	6	*
	7	* (c) 1998 Straylight/Edgeware
	8	*/
	9
	10	/----- Licensing notice --------------------------------------------------
	11	*
	12	* This file is part of the mLib utilities library.
	13	*
	14	* mLib is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU General Public License as published by
	16	* the Free Software Foundation; either version 2 of the License, or
	17	* (at your option) any later version.
	18	*
	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
	22	* GNU General Public License for more details.
	23	*
	24	* You should have received a copy of the GNU General Public License
	25	* along with mLib; if not, write to the Free Software Foundation,
	26	* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	27	*/
	28
	29	/----- Revision history --------------------------------------------------
	30	*
	31	* $Log: exc.c,v $
	32	* Revision 1.1 1998/06/17 23:44:42 mdw
	33	* Initial revision
	34	*
	35	*/
	36
	37	#include <stdarg.h>
	38	#include <stdlib.h>
	39	#include <stdio.h>
	40
	41	#include "exc.h"
	42
	43	/----- Global variables --------------------------------------------------/
	44
	45	__exc_hnd *__exc_list = 0;
	46
	47	/----- Functions ---------------------------------------------------------/
	48
	49	/* --- @exc__duff@ --- *
	50	*
	51	* Arguments: @exc_extype type@ = type of duff exception
	52	* @exc_exval val@ = extra data supplied
	53	*
	54	* Returns: Doesn't
	55	*
	56	* Use: Default handler when everything goes wrong.
	57	*/
	58
	59	static void exc__duff(exc_extype type, exc_exval val)
	60	{
	61	fprintf(stderr, "fatal error: uncaught exception (type = %lu)\n", type);
	62	abort();
	63	}
	64
65	/* --- @exc__duffproc@ --- *
66	*
67	* Current handler when there are no more exceptions left.
68	*/
69
70	static exc__uncaught exc__duffproc = exc__duff;
71
72	/* --- @exc_uncaught@ --- *
73	*
74	* Arguments: @void (*proc)(exc_extype type, exc_exval val) = new handler
75	*
76	* Returns: Pointer to the old handler value.
77	*
78	* Use: Sets the handler for uncaught exceptions.
79	*/
80
81	exc__uncaught exc_uncaught(exc__uncaught proc)
82	{
83	exc__uncaught p = exc__duffproc;
84	if (proc)
85	exc__duffproc = proc;
86	return (p);
87	}
88
89	/* --- @__exc_throw@ --- *
90	*
91	* Arguments: @exc_extype type@ = type of exception to throw
92	*
93	* Returns: Doesn't
94	*
95	* Use: NOT FOR USER CONSUMPTION. Reads an appropriate exception
96	* value and throws an exception.
97	*/
98
99	void __exc_throw(exc_extype type, ...)
100	{
101	va_list ap;
102	exc_exval v;
103
104	va_start(ap, type);
105	switch (type & 0xC0) {
106	case EXC_NOVAL:
107	v.i = 0;
108	break;
109	case EXC_INTVAL:
110	v.i = va_arg(ap, int);
111	break;
112	case EXC_PTRVAL:
113	v.p = va_arg(ap, void *);
114	break;
115	case EXC_STRVAL:
116	v.s = va_arg(ap, char *);
117	break;
118	}
119	va_end(ap);
120	__exc_rethrow(type, v);
121	}
122
123	/* --- @__exc_rethrow@ --- *
124	*
125	* Arguments: @exc_extype type@ = type of exception to throw
126	* @exc_exval val@ = value of exception to throw
127	*
128	* Returns: Doesn't
129	*
130	* Use: NOT FOR USER CONSUMPTION. Does the donkey-work of raising
131	* an exception.
132	*/
133
134	void __exc_rethrow(exc_extype type, exc_exval val)
135	{
136	__exc_hnd *p = __exc_list;
137	if (!p)
138	exc__duffproc(type, val);
139	p->type = type;
140	p->val = val;
141	__exc_list = p->next;
142	longjmp(p->buf, type);
143	}
144
145	/----- That's all, folks -------------------------------------------------/