1 | /* Input handling for G++. |
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2 | Copyright (C) 1992, 1993, 1994, 1995 Free Software Foundation, Inc. |
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3 | Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing. |
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4 | |
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5 | This file is part of GNU CC. |
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6 | |
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7 | GNU CC is free software; you can redistribute it and/or modify |
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8 | it under the terms of the GNU General Public License as published by |
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9 | the Free Software Foundation; either version 2, or (at your option) |
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10 | any later version. |
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11 | |
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12 | GNU CC is distributed in the hope that it will be useful, |
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13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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15 | GNU General Public License for more details. |
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16 | |
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17 | You should have received a copy of the GNU General Public License |
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18 | along with GNU CC; see the file COPYING. If not, write to |
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19 | the Free Software Foundation, 59 Temple Place - Suite 330, |
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20 | Boston, MA 02111-1307, USA. */ |
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21 | |
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22 | /* G++ needs to do enough saving and re-parsing of text that it is |
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23 | necessary to abandon the simple FILE* model and use a mechanism where |
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24 | we can pre-empt one input stream with another derived from saved text; |
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25 | we may need to do this arbitrarily often, and cannot depend on having |
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26 | the GNU library available, so FILE objects just don't cut it. |
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27 | |
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28 | This file is written as a separate module, but can be included by |
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29 | lex.c for very minor efficiency gains (primarily in function |
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30 | inlining). */ |
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31 | |
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32 | #include <stdio.h> |
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33 | #include "obstack.h" |
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34 | |
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35 | extern FILE *finput; |
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36 | |
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37 | struct pending_input *save_pending_input (); |
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38 | void restore_pending_input (); |
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39 | |
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40 | struct input_source { |
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41 | /* saved string */ |
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42 | char *str; |
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43 | int length; |
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44 | /* current position, when reading as input */ |
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45 | int offset; |
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46 | /* obstack to free this input string from when finished, if any */ |
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47 | struct obstack *obstack; |
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48 | /* linked list maintenance */ |
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49 | struct input_source *next; |
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50 | /* values to restore after reading all of current string */ |
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51 | char *filename; |
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52 | int lineno; |
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53 | struct pending_input *input; |
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54 | int putback_char; |
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55 | }; |
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56 | |
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57 | static struct input_source *input, *free_inputs; |
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58 | |
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59 | extern char *input_filename; |
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60 | extern int lineno; |
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61 | |
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62 | #ifdef __GNUC__ |
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63 | #define inline __inline__ |
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64 | #else |
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65 | #define inline |
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66 | #endif |
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67 | |
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68 | static inline struct input_source * |
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69 | allocate_input () |
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70 | { |
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71 | struct input_source *inp; |
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72 | if (free_inputs) |
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73 | { |
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74 | inp = free_inputs; |
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75 | free_inputs = inp->next; |
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76 | inp->next = 0; |
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77 | return inp; |
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78 | } |
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79 | inp = (struct input_source *) xmalloc (sizeof (struct input_source)); |
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80 | inp->next = 0; |
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81 | inp->obstack = 0; |
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82 | return inp; |
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83 | } |
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84 | |
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85 | static inline void |
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86 | free_input (inp) |
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87 | struct input_source *inp; |
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88 | { |
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89 | if (inp->obstack) |
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90 | obstack_free (inp->obstack, inp->str); |
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91 | inp->obstack = 0; |
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92 | inp->str = 0; |
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93 | inp->length = 0; |
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94 | inp->next = free_inputs; |
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95 | free_inputs = inp; |
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96 | } |
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97 | |
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98 | static int putback_char = -1; |
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99 | |
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100 | /* Some of these external functions are declared inline in case this file |
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101 | is included in lex.c. */ |
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102 | |
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103 | inline |
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104 | void |
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105 | feed_input (str, len, delete) |
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106 | char *str; |
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107 | int len; |
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108 | struct obstack *delete; |
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109 | { |
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110 | struct input_source *inp = allocate_input (); |
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111 | |
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112 | /* This shouldn't be necessary. */ |
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113 | while (len && !str[len-1]) |
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114 | len--; |
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115 | |
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116 | inp->str = str; |
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117 | inp->length = len; |
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118 | inp->obstack = delete; |
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119 | inp->offset = 0; |
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120 | inp->next = input; |
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121 | inp->filename = input_filename; |
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122 | inp->lineno = lineno; |
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123 | inp->input = save_pending_input (); |
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124 | inp->putback_char = putback_char; |
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125 | putback_char = -1; |
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126 | input = inp; |
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127 | } |
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128 | |
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129 | struct pending_input *to_be_restored; /* XXX */ |
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130 | extern int end_of_file; |
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131 | |
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132 | static inline int |
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133 | sub_getch () |
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134 | { |
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135 | if (putback_char != -1) |
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136 | { |
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137 | int ch = putback_char; |
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138 | putback_char = -1; |
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139 | return ch; |
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140 | } |
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141 | if (input) |
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142 | { |
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143 | if (input->offset == input->length) |
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144 | { |
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145 | struct input_source *inp = input; |
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146 | my_friendly_assert (putback_char == -1, 223); |
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147 | to_be_restored = inp->input; |
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148 | input->offset++; |
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149 | return EOF; |
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150 | } |
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151 | else if (input->offset > input->length) |
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152 | { |
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153 | struct input_source *inp = input; |
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154 | |
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155 | end_of_file = 0; |
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156 | input = inp->next; |
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157 | input_filename = inp->filename; |
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158 | lineno = inp->lineno; |
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159 | /* Get interface/implementation back in sync. */ |
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160 | extract_interface_info (); |
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161 | putback_char = inp->putback_char; |
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162 | free_input (inp); |
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163 | return getch (); |
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164 | } |
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165 | if (input) |
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166 | return input->str[input->offset++]; |
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167 | } |
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168 | return getc (finput); |
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169 | } |
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170 | |
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171 | inline |
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172 | void |
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173 | put_back (ch) |
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174 | int ch; |
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175 | { |
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176 | if (ch != EOF) |
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177 | { |
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178 | my_friendly_assert (putback_char == -1, 224); |
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179 | putback_char = ch; |
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180 | } |
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181 | } |
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182 | |
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183 | extern int linemode; |
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184 | |
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185 | int |
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186 | getch () |
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187 | { |
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188 | int ch = sub_getch (); |
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189 | if (linemode && ch == '\n') |
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190 | { |
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191 | put_back (ch); |
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192 | ch = EOF; |
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193 | } |
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194 | return ch; |
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195 | } |
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196 | |
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197 | inline |
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198 | int |
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199 | input_redirected () |
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200 | { |
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201 | return input != 0; |
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202 | } |
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