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1 ------------------------------------------------------------------------------
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2 -- --
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3 -- GNAT RUN-TIME COMPONENTS --
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4 -- --
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5 -- S Y S T E M . F I L E _ I O --
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6 -- --
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7 -- S p e c --
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8 -- --
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131
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9 -- Copyright (C) 1992-2018, Free Software Foundation, Inc. --
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111
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10 -- --
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11 -- GNAT is free software; you can redistribute it and/or modify it under --
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12 -- terms of the GNU General Public License as published by the Free Soft- --
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13 -- ware Foundation; either version 3, or (at your option) any later ver- --
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14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
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17 -- --
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18 -- As a special exception under Section 7 of GPL version 3, you are granted --
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19 -- additional permissions described in the GCC Runtime Library Exception, --
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20 -- version 3.1, as published by the Free Software Foundation. --
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21 -- --
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22 -- You should have received a copy of the GNU General Public License and --
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23 -- a copy of the GCC Runtime Library Exception along with this program; --
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24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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25 -- <http://www.gnu.org/licenses/>. --
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26 -- --
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27 -- GNAT was originally developed by the GNAT team at New York University. --
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28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
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29 -- --
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30 ------------------------------------------------------------------------------
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31
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32 -- This package provides support for the routines described in (RM A.8.2)
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33 -- which are common to Text_IO, Direct_IO, Sequential_IO and Stream_IO.
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34
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35 with Interfaces.C_Streams;
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36
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37 with System.File_Control_Block;
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38
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39 package System.File_IO is
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40 pragma Preelaborate;
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41
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42 package FCB renames System.File_Control_Block;
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43 package ICS renames Interfaces.C_Streams;
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44
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45 ---------------------
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46 -- File Management --
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47 ---------------------
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48
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49 procedure Open
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50 (File_Ptr : in out FCB.AFCB_Ptr;
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51 Dummy_FCB : FCB.AFCB'Class;
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52 Mode : FCB.File_Mode;
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53 Name : String;
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54 Form : String;
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55 Amethod : Character;
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56 Creat : Boolean;
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57 Text : Boolean;
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58 C_Stream : ICS.FILEs := ICS.NULL_Stream);
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59 -- This routine is used for both Open and Create calls:
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60 --
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61 -- File_Ptr is the file type, which must be null on entry
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62 -- (i.e. the file must be closed before the call).
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63 --
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64 -- Dummy_FCB is a default initialized file control block of appropriate
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65 -- type. Note that the tag of this record indicates the type and length
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66 -- of the control block. This control block is used only for the purpose
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67 -- of providing the controlling argument for calling the write version
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68 -- of Allocate_AFCB. It has no other purpose, and its fields are never
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69 -- read or written.
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70 --
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71 -- Mode is the required mode
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72 --
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73 -- Name is the file name, with a null string indicating that a temporary
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74 -- file is to be created (only permitted in create mode, not open mode).
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75 --
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76 -- Creat is True for a create call, and false for an open call
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77 --
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78 -- Text is set True to open the file in text mode (w+t or r+t) instead
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79 -- of the usual binary mode open (w+b or r+b).
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80 --
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81 -- Form is the form string given in the open or create call, this is
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82 -- stored in the AFCB.
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83 --
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84 -- Amethod indicates the access method:
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85 --
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86 -- D = Direct_IO
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87 -- Q = Sequential_IO
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88 -- S = Stream_IO
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89 -- T = Text_IO
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90 -- W = Wide_Text_IO
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91 -- ??? Wide_Wide_Text_IO ???
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92 --
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93 -- C_Stream is left at its default value for the normal case of an
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94 -- Open or Create call as defined in the RM. The only time this is
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95 -- non-null is for the Open call from Ada.xxx_IO.C_Streams.Open.
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96 --
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97 -- On return, if the open/create succeeds, then the fields of File are
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98 -- filled in, and this value is copied to the heap. File_Ptr points to
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99 -- this allocated file control block. If the open/create fails, then the
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100 -- fields of File are undefined, and File_Ptr is unchanged.
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101
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102 procedure Close (File_Ptr : access FCB.AFCB_Ptr);
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103 -- The file is closed, all storage associated with it is released, and
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104 -- File is set to null. Note that this routine calls AFCB_Close to perform
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105 -- any specialized close actions, then closes the file at the system level,
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106 -- then frees the mode and form strings, and finally calls AFCB_Free to
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107 -- free the file control block itself, setting File.all to null. Note that
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108 -- for this assignment to be done in all cases, including those where
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109 -- an exception is raised, we can't use an IN OUT parameter (which would
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110 -- not be copied back in case of abnormal return).
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111
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112 procedure Delete (File_Ptr : access FCB.AFCB_Ptr);
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113 -- The indicated file is unlinked
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114
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115 procedure Reset (File_Ptr : access FCB.AFCB_Ptr; Mode : FCB.File_Mode);
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116 -- The file is reset, and the mode changed as indicated
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117
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118 procedure Reset (File_Ptr : access FCB.AFCB_Ptr);
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119 -- The files is reset, and the mode is unchanged
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120
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121 function Mode (File : FCB.AFCB_Ptr) return FCB.File_Mode;
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122 -- Returns the mode as supplied by create, open or reset
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123
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124 function Name (File : FCB.AFCB_Ptr) return String;
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125 -- Returns the file name as supplied by Open or Create. Raises Use_Error
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126 -- if used with temporary files or standard files.
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127
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128 function Form (File : FCB.AFCB_Ptr) return String;
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129 -- Returns the form as supplied by create, open or reset The string is
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130 -- normalized to all lower case letters.
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131
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132 function Is_Open (File : FCB.AFCB_Ptr) return Boolean;
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133 -- Determines if file is open or not
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134
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135 ----------------------
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136 -- Utility Routines --
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137 ----------------------
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138
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139 -- Some internal routines not defined in A.8.2. These are routines which
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140 -- provide required common functionality shared by separate packages.
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141
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142 procedure Chain_File (File : FCB.AFCB_Ptr);
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143 -- Used to chain the given file into the list of open files. Normally this
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144 -- is done implicitly by Open. Chain_File is used for the special cases of
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145 -- the system files defined by Text_IO (stdin, stdout, stderr) which are
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146 -- not opened in the normal manner. Note that the caller is responsible
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147 -- for task lock out to protect the global data structures if this is
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148 -- necessary (it is needed for the calls from within this unit itself,
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149 -- but not required for the calls from Text_IO and [Wide_]Wide_Text_IO
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150 -- that are made during elaboration of the environment task).
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151
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152 procedure Check_File_Open (File : FCB.AFCB_Ptr);
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153 -- If the current file is not open, then Status_Error is raised. Otherwise
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154 -- control returns normally (with File pointing to the control block for
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155 -- the open file.
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156
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157 procedure Check_Read_Status (File : FCB.AFCB_Ptr);
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158 -- If the current file is not open, then Status_Error is raised. If the
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159 -- file is open, then the mode is checked to make sure that reading is
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160 -- permitted, and if not Mode_Error is raised, otherwise control returns
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161 -- normally.
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162
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163 procedure Check_Write_Status (File : FCB.AFCB_Ptr);
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164 -- If the current file is not open, then Status_Error is raised. If the
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165 -- file is open, then the mode is checked to ensure that writing is
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166 -- permitted, and if not Mode_Error is raised, otherwise control returns
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167 -- normally.
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168
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169 function End_Of_File (File : FCB.AFCB_Ptr) return Boolean;
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170 -- File must be opened in read mode. True is returned if the stream is
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171 -- currently positioned at the end of file, otherwise False is returned.
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172 -- The position of the stream is not affected.
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173
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174 procedure Flush (File : FCB.AFCB_Ptr);
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175 -- Flushes the stream associated with the given file. The file must be open
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176 -- and in write mode (if not, an appropriate exception is raised)
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177
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178 function Form_Boolean
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179 (Form : String;
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180 Keyword : String;
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181 Default : Boolean) return Boolean;
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182 -- Searches form string for an entry of the form keyword=xx where xx is
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183 -- either yes/no or y/n. Returns True if yes or y is found, False if no or
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184 -- n is found. If the keyword parameter is not found, returns the value
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185 -- given as Default. May raise Use_Error if a form string syntax error is
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186 -- detected. Keyword and Form must be in lower case.
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187
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188 function Form_Integer
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189 (Form : String;
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190 Keyword : String;
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191 Default : Integer) return Integer;
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192 -- Searches form string for an entry of the form Keyword=xx where xx is an
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193 -- unsigned decimal integer in the range 0 to 999_999. Returns this integer
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194 -- value if it is found. If the keyword parameter is not found, returns the
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195 -- value given as Default. Raise Use_Error if a form string syntax error is
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196 -- detected. Keyword and Form must be in lower case.
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197
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198 procedure Form_Parameter
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199 (Form : String;
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200 Keyword : String;
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201 Start : out Natural;
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202 Stop : out Natural);
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203 -- Searches form string for an entry of the form Keyword=xx and if found
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204 -- Sets Start and Stop to the first and last characters of xx. Keyword
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205 -- and Form must be in lower case. If no entry matches, then Start and
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206 -- Stop are set to zero on return. Use_Error is raised if a malformed
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207 -- string is detected, but there is no guarantee of full syntax checking.
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208
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209 procedure Read_Buf
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210 (File : FCB.AFCB_Ptr;
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211 Buf : Address;
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212 Siz : Interfaces.C_Streams.size_t);
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213 -- Reads Siz bytes from File.Stream into Buf. The caller has checked
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214 -- that the file is open in read mode. Raises an exception if Siz bytes
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215 -- cannot be read (End_Error if no data was read, Data_Error if a partial
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216 -- buffer was read, Device_Error if an error occurs).
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217
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218 procedure Read_Buf
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219 (File : FCB.AFCB_Ptr;
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220 Buf : Address;
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221 Siz : Interfaces.C_Streams.size_t;
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222 Count : out Interfaces.C_Streams.size_t);
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223 -- Reads Siz bytes from File.Stream into Buf. The caller has checked that
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224 -- the file is open in read mode. Device Error is raised if an error
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225 -- occurs. Count is the actual number of bytes read, which may be less
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226 -- than Siz if the end of file is encountered.
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227
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228 procedure Append_Set (File : FCB.AFCB_Ptr);
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229 -- If the mode of the file is Append_File, then the file is positioned at
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230 -- the end of file using fseek, otherwise this call has no effect.
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231
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232 procedure Write_Buf
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233 (File : FCB.AFCB_Ptr;
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234 Buf : Address;
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235 Siz : Interfaces.C_Streams.size_t);
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236 -- Writes size_t bytes to File.Stream from Buf. The caller has checked that
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237 -- the file is open in write mode. Raises Device_Error if the complete
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238 -- buffer cannot be written.
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239
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240 procedure Make_Unbuffered (File : FCB.AFCB_Ptr);
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241
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242 procedure Make_Line_Buffered
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243 (File : FCB.AFCB_Ptr;
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244 Line_Siz : Interfaces.C_Streams.size_t);
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245
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246 procedure Make_Buffered
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247 (File : FCB.AFCB_Ptr;
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248 Buf_Siz : Interfaces.C_Streams.size_t);
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249
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250 private
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251 pragma Inline (Check_Read_Status);
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252 pragma Inline (Check_Write_Status);
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253 pragma Inline (Mode);
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254
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255 end System.File_IO;
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