manual/examples/setjmp.c

   1 /* Introduction to Non-Local Exits
   2    Copyright (C) 1991-2024 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU General Public License
   6    as published by the Free Software Foundation; either version 2
   7    of the License, or (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, see <https://www.gnu.org/licenses/>.
  16 */
  17
  18 #include <setjmp.h>
  19 #include <stdlib.h>
  20 #include <stdio.h>
  21
  22 jmp_buf main_loop;
  23
  24 void
  25 abort_to_main_loop (int status)
  26 {
  27   longjmp (main_loop, status);
  28 }
  29
  30 int
  31 main (void)
  32 {
  33   while (1)
  34     if (setjmp (main_loop))
  35       puts ("Back at main loop....");
  36     else
  37       do_command ();
  38 }
  39
  40
  41 void
  42 do_command (void)
  43 {
  44   char buffer[128];
  45   if (fgets (buffer, 128, stdin) == NULL)
  46     abort_to_main_loop (-1);
  47   else
  48     exit (EXIT_SUCCESS);
  49 }