1  /* Introduction to Non-Local Exits
       2     Copyright (C) 1991-2023 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  }