libgm2/libm2log/Break.c

   1 /* Break.c implements an interrupt handler for SIGINT.
   2
   3 Copyright (C) 2004-2022 Free Software Foundation, Inc.
   4 Contributed by Gaius Mulley <gaius.mulley@southwales.ac.uk>.
   5
   6 This file is part of GNU Modula-2.
   7
   8 GNU Modula-2 is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GNU Modula-2 is distributed in the hope that it will be useful, but
  14 WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 General Public License for more details.
  17
  18 Under Section 7 of GPL version 3, you are granted additional
  19 permissions described in the GCC Runtime Library Exception, version
  20 3.1, as published by the Free Software Foundation.
  21
  22 You should have received a copy of the GNU General Public License and
  23 a copy of the GCC Runtime Library Exception along with this program;
  24 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 <http://www.gnu.org/licenses/>.  */
  26
  27 #include <config.h>
  28
  29 #if defined(HAVE_STDIO_H)
  30 #include <stdio.h>
  31 #endif
  32
  33 #if defined(HAVE_STDARG_H)
  34 #include <stdarg.h>
  35 #endif
  36
  37 #if defined(HAVE_STDLIB_H)
  38 #include <stdlib.h>
  39 #endif
  40
  41 #if defined(HAVE_MALLOC_H)
  42 #include <malloc.h>
  43 #endif
  44
  45 typedef void (*PROC) (void);
  46
  47 #if defined(HAVE_SIGNAL_H)
  48 #include <signal.h>
  49
  50 struct plist
  51 {
  52   PROC proc;
  53   struct plist *next;
  54 };
  55
  56 static struct plist *head = NULL;
  57
  58 /* localHandler - dismisses the parameter, p, and invokes the GNU
  59    Modula-2 handler.  */
  60
  61 static void
  62 localHandler (int p)
  63 {
  64   if (head != NULL)
  65     head->proc ();
  66 }
  67
  68 /* EnableBreak - enable the current break handler.  */
  69
  70 void
  71 Break_EnableBreak (void)
  72 {
  73   signal (SIGINT, localHandler);
  74 }
  75
  76 /* DisableBreak - disable the current break handler (and all
  77    installed handlers).  */
  78
  79 void
  80 Break_DisableBreak (void)
  81 {
  82   signal (SIGINT, SIG_IGN);
  83 }
  84
  85 /* InstallBreak - installs a procedure, p, to be invoked when a
  86    ctrl-c is caught.  Any number of these procedures may be stacked.
  87    Only the top procedure is run when ctrl-c is caught.  */
  88
  89 void
  90 Break_InstallBreak (PROC p)
  91 {
  92   struct plist *q = (struct plist *)malloc (sizeof (struct plist));
  93
  94   if (q == NULL)
  95     {
  96       perror ("out of memory error in module Break");
  97       exit (1);
  98     }
  99   q->next = head;
 100   head = q;
 101   head->proc = p;
 102 }
 103
 104 /* UnInstallBreak - pops the break handler stack.  */
 105
 106 void
 107 Break_UnInstallBreak (void)
 108 {
 109   struct plist *q = head;
 110
 111   if (head != NULL)
 112     {
 113       head = head->next;
 114       free (q);
 115     }
 116 }
 117 #else
 118 void
 119 Break_EnableBreak (void)
 120 {
 121 }
 122 void
 123 Break_DisableBreak (void)
 124 {
 125 }
 126 void
 127 Break_InstallBreak (PROC *p)
 128 {
 129 }
 130 void
 131 Break_UnInstallBreak (void)
 132 {
 133 }
 134 #endif