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1 /* Code shared between all event loops that use select() and have a
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2 different input descriptor for each device.
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3 Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
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4 Copyright (C) 1995 Board of Trustees, University of Illinois.
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5 Copyright (C) 1995 Sun Microsystems, Inc.
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6 Copyright (C) 1995, 1996 Ben Wing.
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7
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8 This file is part of XEmacs.
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9
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10 XEmacs is free software; you can redistribute it and/or modify it
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11 under the terms of the GNU General Public License as published by the
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12 Free Software Foundation; either version 2, or (at your option) any
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13 later version.
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14
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15 XEmacs is distributed in the hope that it will be useful, but WITHOUT
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16 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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17 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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18 for more details.
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19
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20 You should have received a copy of the GNU General Public License
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21 along with XEmacs; see the file COPYING. If not, write to
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22 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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23 Boston, MA 02111-1307, USA. */
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24
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25 /* Synched up with: Not in FSF. */
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26
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27 /* This file has been Mule-ized. */
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28
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29 #include <config.h>
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30 #include "lisp.h"
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31
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32 #include "console-stream.h"
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33 #include "console-tty.h"
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34 #include "device.h"
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35 #include "events.h"
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36 #include "process.h"
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37
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38 #include "sysdep.h"
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39 #include "sysproc.h" /* select stuff */
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40 #include "systime.h"
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41
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42 /* Mask of bits indicating the descriptors that we wait for input on.
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43 These work as follows:
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44
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45 input_wait_mask == mask of all file descriptors we select() on,
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46 including TTY/stream console descriptors,
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47 process descriptors, and the signal event pipe.
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48 Only used in event-tty.c; event-Xt.c uses
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49 XtAppAddInput(), and the call to select() is down in
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50 the guts of Xt.
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51
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52 non_fake_input_wait_mask == same as input_wait_mask but minus the
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53 signal event pipe. Also only used in
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54 event-tty.c.
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55
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56 process_only_mask == only the process descriptors.
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57
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58 tty_only_mask == only the TTY/stream console descriptors.
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59 */
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60 SELECT_TYPE input_wait_mask, non_fake_input_wait_mask;
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61 SELECT_TYPE process_only_mask, tty_only_mask;
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62
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63 /* This is used to terminate the select(), when an event came in
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64 through a signal (e.g. window-change or C-g on controlling TTY). */
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65 int signal_event_pipe[2];
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66
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67 static int signal_event_pipe_initialized;
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68
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69 int fake_event_occurred;
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70
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71 int
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72 read_event_from_tty_or_stream_desc (struct Lisp_Event *event,
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73 struct console *con, int fd)
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74 {
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75 unsigned char ch;
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76 int nread;
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77 Lisp_Object console = Qnil;
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78
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79 XSETCONSOLE (console, con);
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80
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81 nread = read (fd, &ch, 1);
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82 if (nread <= 0)
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83 {
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84 /* deleting the console might not be safe right now ... */
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85 enqueue_magic_eval_event (io_error_delete_console, console);
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86 /* but we definitely need to unselect it to avoid infinite
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87 loops reading EOF's */
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88 Fconsole_disable_input (console);
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89 }
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90 else
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91 {
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92 character_to_event (ch, event, con, 1);
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93 event->channel = console;
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94 return 1;
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95 }
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96 return 0;
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97 }
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98
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99 void
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100 signal_fake_event (void)
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101 {
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102 char byte = 0;
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103 /* We do the write always. Formerly I tried to "optimize" this
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104 by setting a flag indicating whether we're blocking and only
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105 doing the write in that case, but there is a race condition
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106 if the signal occurs after we've checked for the signal
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107 occurrence (which could occur in many places throughout
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108 an iteration of the command loop, e.g. in status_notify()),
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109 but before we set the blocking flag.
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110
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111 This should be OK as long as write() is reentrant, which
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112 I'm fairly sure it is since it's a system call. */
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113
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114 if (signal_event_pipe_initialized)
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115 /* In case a signal comes through while we're dumping */
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116 {
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117 int old_errno = errno;
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118 write (signal_event_pipe[1], &byte, 1);
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119 errno = old_errno;
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120 }
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121 }
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122
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123 void
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124 drain_signal_event_pipe (void)
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125 {
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126 char chars[128];
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127 /* The input end of the pipe has been set to non-blocking. */
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128 while (read (signal_event_pipe[0], chars, sizeof (chars)) > 0)
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129 ;
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130 }
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131
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132 int
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133 event_stream_unixoid_select_console (struct console *con)
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134 {
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135 int infd;
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136
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137 if (CONSOLE_STREAM_P (con))
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138 infd = fileno (CONSOLE_STREAM_DATA (con)->infd);
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139 else
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140 {
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141 assert (CONSOLE_TTY_P (con));
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142 infd = CONSOLE_TTY_DATA (con)->infd;
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143 }
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144
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145 assert (infd >= 0);
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146
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147 FD_SET (infd, &input_wait_mask);
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148 FD_SET (infd, &non_fake_input_wait_mask);
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149 FD_SET (infd, &tty_only_mask);
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150 return infd;
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151 }
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152
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153 int
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154 event_stream_unixoid_unselect_console (struct console *con)
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155 {
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156 int infd;
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157
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158 if (CONSOLE_STREAM_P (con))
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159 infd = fileno (CONSOLE_STREAM_DATA (con)->infd);
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160 else
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161 {
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162 assert (CONSOLE_TTY_P (con));
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163 infd = CONSOLE_TTY_DATA (con)->infd;
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164 }
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165
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166 assert (infd >= 0);
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167
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168 FD_CLR (infd, &input_wait_mask);
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169 FD_CLR (infd, &non_fake_input_wait_mask);
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170 FD_CLR (infd, &tty_only_mask);
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171 return infd;
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172 }
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173
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174 int
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175 event_stream_unixoid_select_process (struct Lisp_Process *proc)
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176 {
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177 int infd, outfd;
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178
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179 get_process_file_descriptors (proc, &infd, &outfd);
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180 assert (infd >= 0);
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181
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182 FD_SET (infd, &input_wait_mask);
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183 FD_SET (infd, &non_fake_input_wait_mask);
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184 FD_SET (infd, &process_only_mask);
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185 return infd;
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186 }
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187
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188 int
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189 event_stream_unixoid_unselect_process (struct Lisp_Process *proc)
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190 {
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191 int infd, outfd;
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192
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193 get_process_file_descriptors (proc, &infd, &outfd);
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194 assert (infd >= 0);
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195
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196 FD_CLR (infd, &input_wait_mask);
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197 FD_CLR (infd, &non_fake_input_wait_mask);
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198 FD_CLR (infd, &process_only_mask);
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199 return infd;
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200 }
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201
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202 int
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203 poll_fds_for_input (SELECT_TYPE mask)
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204 {
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205 EMACS_TIME sometime;
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206 EMACS_SELECT_TIME select_time;
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207 SELECT_TYPE temp_mask;
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208 int retval;
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209
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210 while (1)
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211 {
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212 EMACS_SET_SECS_USECS (sometime, 0, 0);
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213 EMACS_TIME_TO_SELECT_TIME (sometime, select_time);
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214 temp_mask = mask;
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215 /* To effect a poll, tell select() to block for zero seconds. */
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216 retval = select (MAXDESC, &temp_mask, 0, 0, &select_time);
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217 if (retval >= 0)
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218 return retval;
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219 if (errno != EINTR)
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220 {
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221 /* Something went seriously wrong; don't abort since maybe
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222 the TTY just died at the wrong time. */
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223 fprintf (stderr, "xemacs: select failed: errno = %d\n", errno);
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224 return 0;
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225 }
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226 /* else, we got interrupted by a signal, so try again. */
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227 }
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228
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229 RETURN_NOT_REACHED(0) /* not reached */
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230 }
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231
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232
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233 void
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234 init_event_unixoid (void)
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235 {
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236 /* Do this first; the init_event_*_late() functions
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237 pay attention to it. */
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238 if (pipe (signal_event_pipe) < 0)
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239 {
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240 perror ("XEmacs: can't open pipe");
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241 exit (-1);
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242 }
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243 signal_event_pipe_initialized = 1;
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244
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245 /* Set it non-blocking so we can drain its output. */
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246 set_descriptor_non_blocking (signal_event_pipe[0]);
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247
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248 /* Also set the write descriptor non-blocking so we don't
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249 hang in case a long time passes between times when
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250 we drain the pipe. */
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251 set_descriptor_non_blocking (signal_event_pipe[1]);
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252
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253 /* WARNING: In order for the signal-event pipe to work correctly
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254 and not cause lockups, the following need to be followed:
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255
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256 1) event_pending_p() must ignore input on the signal-event pipe.
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257 2) As soon as next_event() notices input on the signal-event
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258 pipe, it must drain it. */
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259 FD_ZERO (&input_wait_mask);
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260 FD_ZERO (&non_fake_input_wait_mask);
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261 FD_ZERO (&process_only_mask);
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262 FD_ZERO (&tty_only_mask);
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263
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264 FD_SET (signal_event_pipe[0], &input_wait_mask);
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265 }
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