1 | .\" Copyright (c) 2011 Kai Wang |
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2 | .\" All rights reserved. |
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3 | .\" |
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5 | .\" modification, are permitted provided that the following conditions |
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6 | .\" are met: |
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9 | .\" 2. Redistributions in binary form must reproduce the above copyright |
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10 | .\" notice, this list of conditions and the following disclaimer in the |
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11 | .\" documentation and/or other materials provided with the distribution. |
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13 | .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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14 | .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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15 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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16 | .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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22 | .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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23 | .\" SUCH DAMAGE. |
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25 | .\" $Id: dwarf_attrval_signed.3 3509 2016-12-29 03:58:41Z emaste $ |
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26 | .\" |
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27 | .Dd December 26, 2016 |
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28 | .Os |
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29 | .Dt DWARF_ATTRVAL_SIGNED 3 |
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30 | .Sh NAME |
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31 | .Nm dwarf_attrval_flag , |
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32 | .Nm dwarf_attrval_signed , |
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33 | .Nm dwarf_attrval_string , |
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34 | .Nm dwarf_attrval_unsigned |
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35 | .Nd retrieve the value of an attribute within a DWARF debugging information entry |
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36 | .Sh LIBRARY |
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37 | .Lb libdwarf |
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38 | .Sh SYNOPSIS |
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39 | .In libdwarf.h |
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40 | .Ft int |
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41 | .Fo dwarf_attrval_flag |
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42 | .Fa "Dwarf_Die die" |
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43 | .Fa "Dwarf_Half attr" |
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44 | .Fa "Dwarf_Bool *ret" |
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45 | .Fa "Dwarf_Error *err" |
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46 | .Fc |
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47 | .Ft int |
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48 | .Fo dwarf_attrval_signed |
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49 | .Fa "Dwarf_Die die" |
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50 | .Fa "Dwarf_Half attr" |
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51 | .Fa "Dwarf_Signed *ret" |
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52 | .Fa "Dwarf_Error *err" |
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53 | .Fc |
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54 | .Ft int |
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55 | .Fo dwarf_attrval_string |
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56 | .Fa "Dwarf_Die die" |
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57 | .Fa "Dwarf_Half attr" |
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58 | .Fa "const char **ret" |
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59 | .Fa "Dwarf_Error *err" |
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60 | .Fc |
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61 | .Ft int |
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62 | .Fo dwarf_attrval_unsigned |
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63 | .Fa "Dwarf_Die die" |
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64 | .Fa "Dwarf_Half attr" |
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65 | .Fa "Dwarf_Unsigned *ret" |
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66 | .Fa "Dwarf_Error *err" |
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67 | .Fc |
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68 | .Sh DESCRIPTION |
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69 | These functions search the debugging information entry referenced |
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70 | by argument |
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71 | .Ar die |
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72 | for the attribute named by argument |
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73 | .Ar attr . |
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74 | If the named attribute is found, the functions set the location |
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75 | pointed to by argument |
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76 | .Ar ret |
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77 | to the value of the attribute. |
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78 | The argument |
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79 | .Ar err , |
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80 | if non NULL, |
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81 | will be used to return an error descriptor in case of an error. |
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82 | .Pp |
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83 | Function |
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84 | .Fn dwarf_attrval_flag |
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85 | sets the location pointed to by argument |
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86 | .Ar ret |
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87 | to either 0 or 1. If the form of the attribute named by argument |
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88 | .Ar attr |
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89 | is |
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90 | .Dv DW_FORM_flag , |
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91 | function |
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92 | .Fn dwarf_attrval_flag |
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93 | sets the location pointed to by argument |
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94 | .Ar ret |
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95 | to 1 if the attribute has a non-zero value, or to 0 otherwise. |
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96 | If the form of the attribute named by argument |
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97 | .Ar attr |
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98 | is |
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99 | .Dv DW_FORM_flag_present , |
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100 | function |
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101 | .Fn dwarf_attrval_flag |
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102 | unconditionally sets the location pointed to by argument |
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103 | .Ar ret |
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104 | to 1. |
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105 | The form of the attribute must be one of |
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106 | .Dv DW_FORM_flag |
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107 | or |
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108 | .Dv DW_FORM_flag_present . |
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109 | .Pp |
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110 | Function |
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111 | .Fn dwarf_attrval_signed |
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112 | stores the value for the attribute named by argument |
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113 | .Ar attr , |
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114 | into the location pointed to by argument |
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115 | .Ar ret . |
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116 | The attribute's value is treated as a signed integral quantity and is |
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117 | sign-extended as needed. |
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118 | The attribute named by the argument |
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119 | .Ar attr |
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120 | must belong to the |
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121 | .Dv CONSTANT |
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122 | class and must have one of the following forms: |
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123 | .Dv DW_FORM_data1 , |
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124 | .Dv DW_FORM_data2 , |
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125 | .Dv DW_FORM_data4 , |
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126 | .Dv DW_FORM_data8 |
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127 | or |
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128 | .Dv DW_FORM_sdata . |
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129 | .Pp |
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130 | Function |
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131 | .Fn dwarf_attrval_string |
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132 | sets the location pointed to by argument |
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133 | .Ar ret |
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134 | to a pointer to a NUL-terminated string that is the value of the |
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135 | attribute named by argument |
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136 | .Ar attr . |
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137 | The form of the attribute must be one of |
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138 | .Dv DW_FORM_string |
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139 | or |
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140 | .Dv DW_FORM_strp . |
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141 | .Pp |
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142 | Function |
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143 | .Fn dwarf_attrval_unsigned |
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144 | stores the value for the attribute named by argument |
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145 | .Ar attr |
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146 | into the location pointed to by argument |
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147 | .Ar ret . |
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148 | The attribute's value is treated as an unsigned integral quantity, and |
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149 | is zero-extended as needed. |
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150 | The named attribute must belong to one of the |
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151 | .Dv CONSTANT , |
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152 | .Dv ADDRESS |
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153 | or |
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154 | .Dv REFERENCE |
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155 | classes and must have one of the following forms: |
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156 | .Dv DW_FORM_addr , |
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157 | .Dv DW_FORM_data1 , |
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158 | .Dv DW_FORM_data2 , |
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159 | .Dv DW_FORM_data4 , |
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160 | .Dv DW_FORM_data8 , |
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161 | .Dv DW_FORM_udata , |
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162 | .Dv DW_FORM_ref1 , |
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163 | .Dv DW_FORM_ref2 , |
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164 | .Dv DW_FORM_ref4 , |
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165 | .Dv DW_FORM_ref8 , |
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166 | or |
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167 | .Dv DW_FORM_ref_udata . |
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168 | .Pp |
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169 | If the attribute named by argument |
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170 | .Ar attr |
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171 | is |
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172 | .Dv DW_AT_type |
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173 | and is not present in the debugging information entry referenced by argument |
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174 | .Ar die , |
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175 | and if a |
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176 | .Dv DW_AT_abstract_origin |
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177 | or |
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178 | .Dv DW_AT_specification |
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179 | attribute is present in the debugging information entry, |
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180 | function |
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181 | .Fn dwarf_attrval_unsigned |
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182 | will search for the named attribute in the debugging information entry |
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183 | referenced by the |
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184 | .Dv DW_AT_abstract_origin |
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185 | or |
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186 | .Dv DW_AT_specification |
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187 | attribute. |
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188 | .Sh RETURN VALUES |
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189 | On success, these functions returns |
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190 | .Dv DW_DLV_OK . |
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191 | If the named attribute was not found in the specified debugging |
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192 | information entry descriptor these functions return |
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193 | .Dv DW_DLV_NO_ENTRY |
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194 | and set argument |
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195 | .Ar err . |
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196 | For other errors, these functions return |
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197 | .Dv DW_DLV_ERROR |
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198 | and set argument |
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199 | .Ar err . |
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200 | .Sh COMPATIBILITY |
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201 | These functions are extensions added by this implementation of the |
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202 | DWARF(3) API. |
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203 | .Sh ERRORS |
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204 | These functions may fail with the following errors: |
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205 | .Bl -tag -width ".Bq Er DW_DLE_ATTR_FORM_BAD" |
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206 | .It Bq Er DW_DLE_ARGUMENT |
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207 | Either of the arguments |
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208 | .Va die |
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209 | or |
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210 | .Va ret |
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211 | was NULL. |
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212 | .It Bq Er DW_DLE_NO_ENTRY |
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213 | Argument |
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214 | .Ar die |
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215 | did not contain an attribute corresponding to the value in argument |
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216 | .Ar attr . |
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217 | .It Bq Er DW_DLE_ATTR_FORM_BAD |
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218 | The attribute named by argument |
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219 | .Ar attr |
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220 | was not of a permitted form. |
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221 | .El |
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222 | .Sh SEE ALSO |
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223 | .Xr dwarf 3 , |
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224 | .Xr dwarf_attr 3 , |
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225 | .Xr dwarf_hasattr 3 |
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