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1 /* |
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2 |
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3 Copyright (C) 1996, 1997 John W. Eaton |
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4 |
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5 This file is part of Octave. |
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6 |
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7 Octave is free software; you can redistribute it and/or modify it |
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8 under the terms of the GNU General Public License as published by the |
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9 Free Software Foundation; either version 2, or (at your option) any |
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10 later version. |
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11 |
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12 Octave is distributed in the hope that it will be useful, but WITHOUT |
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13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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15 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 Octave; see the file COPYING. If not, write to the Free |
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19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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20 |
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21 */ |
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22 |
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23 #if defined (__GNUG__) |
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24 #pragma implementation |
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25 #endif |
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26 |
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27 #ifdef HAVE_CONFIG_H |
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28 #include <config.h> |
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29 #endif |
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30 |
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31 // Nonzero means we're breaking out of a loop or function body. |
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32 extern int breaking; |
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33 |
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34 // Nonzero means we're jumping to the end of a loop. |
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35 extern int continuing; |
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36 |
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37 // Nonzero means we're returning from a function. Global because it |
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38 // is also needed in tree-expr.cc. |
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39 extern int returning; |
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40 |
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41 #include "error.h" |
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42 #include "oct-lvalue.h" |
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43 #include "ov.h" |
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44 #include "pt-cmd.h" |
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45 #include "pt-except.h" |
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46 #include "pt-exp.h" |
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47 #include "pt-stmt.h" |
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48 #include "pt-walk.h" |
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49 #include "unwind-prot.h" |
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50 #include "variables.h" |
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51 |
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52 // Simple exception handling. |
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53 |
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54 tree_try_catch_command::~tree_try_catch_command (void) |
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55 { |
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56 delete try_code; |
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57 delete catch_code; |
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58 } |
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59 |
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60 static void |
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61 do_catch_code (void *ptr) |
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62 { |
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63 tree_statement_list *list = static_cast<tree_statement_list *> (ptr); |
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64 |
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65 // Set up for letting the user print any messages from errors that |
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66 // occurred in the body of the try_catch statement. |
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67 |
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68 buffer_error_messages = 0; |
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69 bind_global_error_variable (); |
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70 add_unwind_protect (clear_global_error_variable, 0); |
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71 |
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72 // Similarly, if we have seen a return or break statement, allow all |
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73 // the catch code to run before returning or handling the break. |
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74 // We don't have to worry about continue statements because they can |
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75 // only occur in loops. |
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76 |
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77 unwind_protect_int (returning); |
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78 returning = 0; |
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79 |
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80 unwind_protect_int (breaking); |
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81 breaking = 0; |
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82 |
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83 if (list) |
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84 list->eval (); |
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85 |
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86 // This is the one for breaking. (The unwind_protects are popped |
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87 // off the stack in the reverse of the order they are pushed on). |
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88 |
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89 // XXX FIXME XXX -- inside a try-catch, should break work like |
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90 // a return, or just jump to the end of the try_catch block? |
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91 // The following code makes it just jump to the end of the block. |
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92 |
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93 run_unwind_protect (); |
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94 if (breaking) |
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95 breaking--; |
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96 |
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97 // This is the one for returning. |
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98 |
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99 if (returning) |
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100 discard_unwind_protect (); |
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101 else |
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102 run_unwind_protect (); |
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103 |
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104 run_unwind_protect (); |
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105 } |
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106 |
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107 void |
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108 tree_try_catch_command::eval (void) |
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109 { |
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110 begin_unwind_frame ("tree_try_catch::eval"); |
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111 |
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112 add_unwind_protect (do_catch_code, catch_code); |
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113 |
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114 if (catch_code) |
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115 { |
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116 unwind_protect_int (buffer_error_messages); |
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117 buffer_error_messages = 1; |
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118 } |
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119 |
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120 if (try_code) |
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121 try_code->eval (); |
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122 |
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123 if (catch_code && error_state) |
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124 { |
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125 error_state = 0; |
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126 run_unwind_frame ("tree_try_catch::eval"); |
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127 } |
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128 else |
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129 { |
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130 error_state = 0; |
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131 discard_unwind_frame ("tree_try_catch::eval"); |
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132 } |
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133 } |
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134 |
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135 void |
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136 tree_try_catch_command::accept (tree_walker& tw) |
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137 { |
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138 tw.visit_try_catch_command (*this); |
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139 } |
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140 |
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141 // Simple exception handling. |
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142 |
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143 tree_unwind_protect_command::~tree_unwind_protect_command (void) |
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144 { |
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145 delete unwind_protect_code; |
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146 delete cleanup_code; |
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147 } |
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148 |
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149 static void |
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150 do_unwind_protect_cleanup_code (void *ptr) |
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151 { |
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152 tree_statement_list *list = static_cast<tree_statement_list *> (ptr); |
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153 |
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154 // We want to run the cleanup code without error_state being set, |
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155 // but we need to restore its value, so that any errors encountered |
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156 // in the first part of the unwind_protect are not completely |
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157 // ignored. |
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158 |
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159 unwind_protect_int (error_state); |
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160 error_state = 0; |
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161 |
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162 // Similarly, if we have seen a return or break statement, allow all |
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163 // the cleanup code to run before returning or handling the break. |
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164 // We don't have to worry about continue statements because they can |
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165 // only occur in loops. |
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166 |
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167 unwind_protect_int (returning); |
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168 returning = 0; |
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169 |
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170 unwind_protect_int (breaking); |
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171 breaking = 0; |
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172 |
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173 if (list) |
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174 list->eval (); |
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175 |
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176 // This is the one for breaking. (The unwind_protects are popped |
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177 // off the stack in the reverse of the order they are pushed on). |
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178 |
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179 // XXX FIXME XXX -- inside an unwind_protect, should break work like |
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180 // a return, or just jump to the end of the unwind_protect block? |
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181 // The following code makes it just jump to the end of the block. |
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182 |
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183 run_unwind_protect (); |
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184 if (breaking) |
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185 breaking--; |
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186 |
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187 // This is the one for returning. |
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188 |
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189 if (returning) |
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190 discard_unwind_protect (); |
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191 else |
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192 run_unwind_protect (); |
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193 |
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194 // We don't want to ignore errors that occur in the cleanup code, so |
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195 // if an error is encountered there, leave error_state alone. |
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196 // Otherwise, set it back to what it was before. |
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197 |
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198 if (error_state) |
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199 discard_unwind_protect (); |
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200 else |
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201 run_unwind_protect (); |
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202 } |
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203 |
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204 void |
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205 tree_unwind_protect_command::eval (void) |
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206 { |
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207 add_unwind_protect (do_unwind_protect_cleanup_code, cleanup_code); |
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208 |
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209 if (unwind_protect_code) |
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210 unwind_protect_code->eval (); |
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211 |
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212 run_unwind_protect (); |
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213 } |
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214 |
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215 void |
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216 tree_unwind_protect_command::accept (tree_walker& tw) |
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217 { |
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218 tw.visit_unwind_protect_command (*this); |
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219 } |
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220 |
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221 /* |
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222 ;;; Local Variables: *** |
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223 ;;; mode: C++ *** |
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224 ;;; End: *** |
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225 */ |
