c_cpp/etc/calc/math_error.c

   1 /*
   2  * math_error - a simple libcalc math error routine
   3  *
   4  * Copyright (C) 1999  Landon Curt Noll
   5  *
   6  * Calc is open software; you can redistribute it and/or modify it under
   7  * the terms of the version 2.1 of the GNU Lesser General Public License
   8  * as published by the Free Software Foundation.
   9  *
  10  * Calc is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General
  13  * Public License for more details.
  14  *
  15  * A copy of version 2.1 of the GNU Lesser General Public License is
  16  * distributed with calc under the filename COPYING-LGPL.  You should have
  17  * received a copy with calc; if not, write to Free Software Foundation, Inc.
  18  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19  *
  20  * @(#) $Revision: 30.2 $
  21  * @(#) $Id: math_error.c,v 30.2 2008/10/24 09:49:20 chongo Exp $
  22  * @(#) $Source: /usr/local/src/bin/calc/RCS/math_error.c,v $
  23  *
  24  * Under source code control:   1994/08/03 05:08:22
  25  * File existed as early as:    1994
  26  *
  27  * chongo <was here> /\oo/\     http://www.isthe.com/chongo/
  28  * Share and enjoy!  :-)        http://www.isthe.com/chongo/tech/comp/calc/
  29  */
  30
  31 /*
  32  * Your program MUST provide a function called math_error.  This is called
  33  * by the math routines on an error condition, such as malloc failures or a
  34  * division by zero.  The routine is called in the manner of printf, with a
  35  * format string and optional arguments.
  36  *
  37  * By default, this routine simply prints a message to stderr and then exits.
  38  *
  39  * If one sets up calc_matherr_jmpbuf, and then sets calc_use_matherr_jmpbuf
  40  * to non-zero then this routine will longjmp back with the return value of
  41  * calc_use_matherr_jmpbuf.  In addition, the last calc error message will be
  42  * found in calc_use_matherr_jmpbuf_msg.  This error is not printed to sttderr.
  43  *
  44  * For example:
  45  *
  46  *      #include <setjmp.h>
  47  *      #include "lib_calc.h"
  48  *
  49  *      int error;
  50  *
  51  *      ...
  52  *
  53  *      if ((error = setjmp(calc_matherr_jmpbuf)) != 0) {
  54  *
  55  *              (* reinitialize calc after a longjmp *)
  56  *              reinitialize();
  57  *
  58  *              (* report the error *)
  59  *              printf("Ouch: %s\n", calc_err_msg);
  60  *      }
  61  *      calc_use_matherr_jmpbuf = 1;
  62  */
  63
  64
  65 #include <stdio.h>
  66 #include <setjmp.h>
  67 #include "args.h"
  68 #include "calc.h"
  69 #include "lib_calc.h"
  70
  71
  72 /*
  73  * math_error - print a math error and exit
  74  */
  75 void
  76 math_error(char *fmt, ...)
  77 {
  78         va_list ap;
  79
  80         /*
  81          * format the error
  82          */
  83 #ifdef VARARGS
  84         va_start(ap);
  85 #else
  86         va_start(ap, fmt);
  87 #endif
  88         vsnprintf(calc_err_msg, MAXERROR, fmt, ap);
  89         va_end(ap);
  90         calc_err_msg[MAXERROR] = '\0';
  91
  92         /*
  93          * if we should longjmp, so do
  94          */
  95         if (calc_use_matherr_jmpbuf != 0) {
  96                 if (conf->calc_debug & CALCDBG_RUNSTATE)
  97                         printf("math_error: longjmp calc_matherr_jmpbuf\n");
  98                 longjmp(calc_matherr_jmpbuf, calc_use_matherr_jmpbuf);
  99         }
 100
 101         /*
 102          * print error message and edit
 103          */
 104         (void) fflush(stdout);
 105         (void) fflush(stderr);
 106         fprintf(stderr, "%s\n\n", calc_err_msg);
 107
 108         /*
 109          * if interactive, return to main via longjmp()
 110          */
 111         if (calc_use_scanerr_jmpbuf != 0) {
 112                 if (conf->calc_debug & CALCDBG_RUNSTATE)
 113                         printf("math_error: longjmp calc_scanerr_jmpbuf\n");
 114                 longjmp(calc_scanerr_jmpbuf, calc_use_scanerr_jmpbuf);
 115         }
 116
 117         /*
 118          * exit
 119          */
 120         if (conf->calc_debug & CALCDBG_RUNSTATE)
 121                 printf("math_error: about to exit\n");
 122         libcalc_call_me_last();
 123         exit(40);
 124 }