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428
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1 /* The lisp stack.
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2 Copyright (C) 1985, 1986, 1987, 1992, 1993 Free Software Foundation, Inc.
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853
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3 Copyright (C) 2002 Ben Wing.
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428
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4
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5 This file is part of XEmacs.
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6
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7 XEmacs 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 XEmacs 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 XEmacs; see the file COPYING. If not, write to
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19 the Free Software Foundation, Inc., 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 /* Synched up with: FSF 19.30. Contained redundantly in various C files
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23 in FSFmacs. */
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24
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25 /* Authorship:
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26
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27 FSF: Original version; a long time ago.
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28 XEmacs: split out of some C files. (For some obscure reason, a header
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29 file couldn't be used in FSF Emacs, but XEmacs doesn't have
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30 that problem.)
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31 Mly (probably) or JWZ: Some changes.
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32 */
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33
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440
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34 #ifndef INCLUDED_backtrace_h_
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35 #define INCLUDED_backtrace_h_
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428
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36
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37 #include <setjmp.h>
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38
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853
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39 #ifdef ERROR_CHECK_CATCH
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40 /* you can use this if you are trying to debug corruption in the
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41 catchlist */
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42 void check_catchlist_sanity (void);
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43
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44 /* you can use this if you are trying to debug corruption in the specbind
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45 stack */
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46 void check_specbind_stack_sanity (void);
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47 #else
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48 #define check_catchlist_sanity()
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49 #define check_specbind_stack_sanity()
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50 #endif
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51
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428
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52 /* These definitions are used in eval.c and alloc.c */
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53
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54 struct backtrace
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55 {
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56 struct backtrace *next;
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57 Lisp_Object *function;
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58 Lisp_Object *args; /* Points to vector of args. */
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59 int nargs; /* Length of vector.
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60 If nargs is UNEVALLED, args points to
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61 slot holding list of unevalled args */
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62 int pdlcount; /* specpdl_depth () when invoked */
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63 char evalargs;
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64 /* Nonzero means call value of debugger when done with this operation. */
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65 char debug_on_exit;
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66 };
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67
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68 /* This structure helps implement the `catch' and `throw' control
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69 structure. A struct catchtag contains all the information needed
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70 to restore the state of the interpreter after a non-local jump.
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853
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71 (No information is stored concerning how to restore the state of
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72 the condition-handler list; this is handled implicitly through
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73 an unwind-protect. unwind-protects are on the specbind stack,
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74 which is reset to its proper value by `throw'. In the process of
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75 that, any intervening bindings are reset and unwind-protects called,
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76 which fixes up the condition-handler list.
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428
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77
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78 catchtag structures are chained together in the C calling stack;
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79 the `next' member points to the next outer catchtag.
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80
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81 A call like (throw TAG VAL) searches for a catchtag whose `tag'
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853
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82 member is TAG, and then unbinds to it. A value of Vcatch_everything_tag
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83 for the `tag' member of a catchtag is special and means "catch all throws,
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84 regardless of the tag". This is used internally by the C code. The `val'
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85 member is used to hold VAL while the stack is unwound; `val' is returned
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86 as the value of the catch form. The `actual_tag' member holds the value
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87 of TAG as passed to throw, so that it can be retrieved when catches with
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88 Vcatch_everything_tag are set up.
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428
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89
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90 All the other members are concerned with restoring the interpreter
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91 state. */
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92
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93 struct catchtag
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94 {
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95 Lisp_Object tag;
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853
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96 /* Stores the actual tag used in `throw'; the same as TAG, unless
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97 TAG is Vcatch_everything_tag. */
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98 Lisp_Object actual_tag;
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428
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99 Lisp_Object val;
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100 struct catchtag *next;
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101 struct gcpro *gcpro;
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102 JMP_BUF jmp;
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103 struct backtrace *backlist;
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104 #if 0 /* FSFmacs */
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617
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105 /* FSF uses a separate handler stack to hold condition-cases,
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106 where we use Vcondition_handlers. We should switch to their
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107 system becaue it avoids the need to mess around with consing
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108 up stuff and then dangerously freeing it. See comment in
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109 condition_case_unwind(). */
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428
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110 struct handler *handlerlist;
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111 #endif
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112 int lisp_eval_depth;
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113 int pdlcount;
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114 #if 0 /* FSFmacs */
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115 /* This is the equivalent of async_timer_suppress_count.
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116 We probably don't have to bother with this. */
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117 int poll_suppress_count;
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118 #endif
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119 };
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120
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121 /* Dynamic-binding-o-rama */
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122
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123 /* Structure for recording Lisp call stack for backtrace purposes. */
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124
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125 /* The special binding stack holds the outer values of variables while
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126 they are bound by a function application or a let form, stores the
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127 code to be executed for Lisp unwind-protect forms, and stores the C
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128 functions to be called for record_unwind_protect.
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129
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130 If func is non-zero, undoing this binding applies func to old_value;
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131 This implements record_unwind_protect.
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132 If func is zero and symbol is nil, undoing this binding evaluates
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133 the list of forms in old_value; this implements Lisp's unwind-protect
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134 form.
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135 Otherwise, undoing this binding stores old_value as symbol's value; this
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136 undoes the bindings made by a let form or function call. */
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137
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138 struct specbinding
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139 {
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140 Lisp_Object symbol;
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141 Lisp_Object old_value;
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142 Lisp_Object (*func) (Lisp_Object); /* for unwind-protect */
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143 };
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144
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145 #if 0 /* FSFmacs */
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146 /* #### */
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147 /* Everything needed to describe an active condition case. */
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148 struct handler
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149 {
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150 /* The handler clauses and variable from the condition-case form. */
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151 Lisp_Object handler;
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152 Lisp_Object var;
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153 /* Fsignal stores here the condition-case clause that applies,
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154 and Fcondition_case thus knows which clause to run. */
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155 Lisp_Object chosen_clause;
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156
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157 /* Used to effect the longjmp() out to the handler. */
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158 struct catchtag *tag;
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159
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160 /* The next enclosing handler. */
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161 struct handler *next;
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162 };
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163
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164 extern struct handler *handlerlist;
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165
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166 #endif
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167
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168 /* These are extern because GC needs to mark them */
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169 extern struct specbinding *specpdl;
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170 extern struct specbinding *specpdl_ptr;
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171 extern struct catchtag *catchlist;
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172 extern struct backtrace *backtrace_list;
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173
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771
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174 /* Most callers should simply use specbind() and unbind_to_1(), but if
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428
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175 speed is REALLY IMPORTANT, you can use the faster macros below */
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176 void specbind_magic (Lisp_Object, Lisp_Object);
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647
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177 void grow_specpdl (EMACS_INT reserved);
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428
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178 void unbind_to_hairy (int);
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179 extern int specpdl_size;
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180
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181 /* Inline version of specbind().
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182 Use this instead of specbind() if speed is sufficiently important
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183 to save the overhead of even a single function call. */
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184 #define SPECBIND(symbol_object, value_object) do { \
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185 Lisp_Object SB_symbol = (symbol_object); \
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186 Lisp_Object SB_newval = (value_object); \
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187 Lisp_Object SB_oldval; \
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440
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188 Lisp_Symbol *SB_sym; \
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428
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189 \
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190 SPECPDL_RESERVE (1); \
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191 \
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192 CHECK_SYMBOL (SB_symbol); \
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193 SB_sym = XSYMBOL (SB_symbol); \
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194 SB_oldval = SB_sym->value; \
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195 \
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196 if (!SYMBOL_VALUE_MAGIC_P (SB_oldval) || UNBOUNDP (SB_oldval)) \
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197 { \
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440
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198 /* #### the following test will go away when we have a constant \
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428
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199 symbol magic object */ \
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200 if (EQ (SB_symbol, Qnil) || \
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201 EQ (SB_symbol, Qt) || \
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202 SYMBOL_IS_KEYWORD (SB_symbol)) \
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203 reject_constant_symbols (SB_symbol, SB_newval, 0, \
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204 UNBOUNDP (SB_newval) ? \
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205 Qmakunbound : Qset); \
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206 \
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207 specpdl_ptr->symbol = SB_symbol; \
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208 specpdl_ptr->old_value = SB_oldval; \
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209 specpdl_ptr->func = 0; \
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210 specpdl_ptr++; \
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211 specpdl_depth_counter++; \
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212 \
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213 SB_sym->value = (SB_newval); \
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214 } \
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215 else \
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216 specbind_magic (SB_symbol, SB_newval); \
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853
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217 check_specbind_stack_sanity (); \
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428
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218 } while (0)
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219
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220 /* An even faster, but less safe inline version of specbind().
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221 Caller guarantees that:
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222 - SYMBOL is a non-constant symbol (i.e. not Qnil, Qt, or keyword).
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223 - specpdl_depth_counter >= specpdl_size.
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224 Else we crash. */
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225 #define SPECBIND_FAST_UNSAFE(symbol_object, value_object) do { \
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226 Lisp_Object SFU_symbol = (symbol_object); \
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227 Lisp_Object SFU_newval = (value_object); \
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440
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228 Lisp_Symbol *SFU_sym = XSYMBOL (SFU_symbol); \
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428
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229 Lisp_Object SFU_oldval = SFU_sym->value; \
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814
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230 /* Most of the time, will be previously unbound. #### With a bit of \
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231 rearranging, this could be reduced to only one check. */ \
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232 if (UNBOUNDP (SFU_oldval) || !SYMBOL_VALUE_MAGIC_P (SFU_oldval)) \
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428
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233 { \
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234 specpdl_ptr->symbol = SFU_symbol; \
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235 specpdl_ptr->old_value = SFU_oldval; \
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236 specpdl_ptr->func = 0; \
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237 specpdl_ptr++; \
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238 specpdl_depth_counter++; \
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239 \
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240 SFU_sym->value = (SFU_newval); \
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241 } \
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242 else \
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243 specbind_magic (SFU_symbol, SFU_newval); \
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853
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244 check_specbind_stack_sanity (); \
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428
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245 } while (0)
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246 /* Request enough room for SIZE future entries on special binding stack */
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247 #define SPECPDL_RESERVE(size) do { \
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647
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248 EMACS_INT SR_size = (size); \
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428
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249 if (specpdl_depth() + SR_size >= specpdl_size) \
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250 grow_specpdl (SR_size); \
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251 } while (0)
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252
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771
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253 /* Inline version of unbind_to_1().
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254 [[Use this instead of unbind_to_1() if speed is sufficiently important
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255 to save the overhead of even a single function call.]]
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256 This is bogus pseudo-optimization. --ben
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428
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257
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771
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258 Most of the time, unbind_to_1() is called only on ordinary
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428
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259 variables, so optimize for that. */
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260 #define UNBIND_TO_GCPRO(count, value) do { \
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261 int UNBIND_TO_count = (count); \
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262 while (specpdl_depth_counter != UNBIND_TO_count) \
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263 { \
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440
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264 Lisp_Symbol *sym; \
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428
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265 --specpdl_ptr; \
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266 --specpdl_depth_counter; \
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267 \
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268 if (specpdl_ptr->func != 0 || \
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269 ((sym = XSYMBOL (specpdl_ptr->symbol)), \
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270 SYMBOL_VALUE_MAGIC_P (sym->value))) \
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271 { \
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272 struct gcpro gcpro1; \
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273 GCPRO1 (value); \
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274 unbind_to_hairy (UNBIND_TO_count); \
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275 UNGCPRO; \
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276 break; \
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277 } \
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278 \
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279 sym->value = specpdl_ptr->old_value; \
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280 } \
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853
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281 check_specbind_stack_sanity (); \
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428
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282 } while (0)
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283
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771
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284 /* A slightly faster inline version of unbind_to_1,
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428
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285 that doesn't offer GCPROing services. */
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286 #define UNBIND_TO(count) do { \
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287 int UNBIND_TO_count = (count); \
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288 while (specpdl_depth_counter != UNBIND_TO_count) \
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289 { \
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440
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290 Lisp_Symbol *sym; \
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428
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291 --specpdl_ptr; \
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292 --specpdl_depth_counter; \
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293 \
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294 if (specpdl_ptr->func != 0 || \
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295 ((sym = XSYMBOL (specpdl_ptr->symbol)), \
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296 SYMBOL_VALUE_MAGIC_P (sym->value))) \
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297 { \
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298 unbind_to_hairy (UNBIND_TO_count); \
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299 break; \
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300 } \
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301 \
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302 sym->value = specpdl_ptr->old_value; \
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303 } \
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853
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304 check_specbind_stack_sanity (); \
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428
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305 } while (0)
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306
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307 #if 0
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308 /* Unused. It's too hard to guarantee that the current bindings
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309 contain only variables. */
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771
|
310 /* Another inline version of unbind_to_1(). VALUE is GC-protected.
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428
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311 Caller guarantees that:
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312 - all of the elements on the binding stack are variable bindings.
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313 Else we crash. */
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314 #define UNBIND_TO_GCPRO_VARIABLES_ONLY(count, value) do { \
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315 int UNBIND_TO_count = (count); \
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316 while (specpdl_depth_counter != UNBIND_TO_count) \
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317 { \
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440
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318 Lisp_Symbol *sym; \
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428
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319 --specpdl_ptr; \
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320 --specpdl_depth_counter; \
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321 \
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322 sym = XSYMBOL (specpdl_ptr->symbol); \
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323 if (!SYMBOL_VALUE_MAGIC_P (sym->value)) \
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324 sym->value = specpdl_ptr->old_value; \
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325 else \
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326 { \
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327 struct gcpro gcpro1; \
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328 GCPRO1 (value); \
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329 unbind_to_hairy (UNBIND_TO_count); \
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330 UNGCPRO; \
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331 break; \
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332 } \
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333 } \
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|
|
334 } while (0)
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|
335 #endif /* unused */
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336
|
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|
337 /* A faster, but less safe inline version of Fset().
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338 Caller guarantees that:
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339 - SYMBOL is a non-constant symbol (i.e. not Qnil, Qt, or keyword).
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340 Else we crash. */
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341 #define FSET_FAST_UNSAFE(sym, newval) do { \
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342 Lisp_Object FFU_sym = (sym); \
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|
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343 Lisp_Object FFU_newval = (newval); \
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440
|
344 Lisp_Symbol *FFU_symbol = XSYMBOL (FFU_sym); \
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428
|
345 Lisp_Object FFU_oldval = FFU_symbol->value; \
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346 if (!SYMBOL_VALUE_MAGIC_P (FFU_oldval) || UNBOUNDP (FFU_oldval)) \
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347 FFU_symbol->value = FFU_newval; \
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348 else \
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349 Fset (FFU_sym, FFU_newval); \
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|
|
350 } while (0)
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351
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440
|
352 #endif /* INCLUDED_backtrace_h_ */
|
