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  Arguments
 
    file_variable    Optional; text or typed file (default is
                     standard file Input)
 
    variables        One required, others optional; for text files,
                     variable of any simple type except Boolean; for
                     typed files, variable of same type as component
                     type of file
 
  Description
 
    The Read procedure copies one or more values from a disk file or a
    device and places them into variables. The file must be open.
    After reading the file, Read advances the current file position to
    the next component.
 
    If the file is a text file, it must be opened for input by using
    the Reset procedure. A text file is read sequentially.
 
    If the file is a typed file, it can be opened with either Reset
    or the Rewrite procedure. A typed file can be read from or written
    to at any position.
 
    If no input file is specified, Read reads from the standard text
    file Input. Standard input is from the keyboard unless redirected
    from a file by the DOS redirection operator, (<). Read waits for all
    arguments to be entered when reading multiple arguments from the
    keyboard. Each input ends after a delimiting character for that
    type is entered. All types end when Enter is pressed. Keyboard
    input is echoed on the screen.
 
    Input redirection is disabled when the Crt unit is used. Use the
    Assign procedure with a null string to reenable DOS redirection
    when using Crt.
 
    Read copies values depending on the input and the variable types:
 
      1. Character input is read without use of delimiters.
 
         When Read is called with a text file and character variable,
         and the current position is at end-of-line, it reads a
         carriage return (ASCII 13) and moves the current position to
         the character following the carriage return.
 
         When Read is called for a text file and a char variable, and
         the current position is at end-of-file, it reads a CTRL+Z
         (ASCII 26). Subsequent calls to Read get CTRL+Z.
 
      2. Number input is delimited by blanks, tabs, or end-of-line
         markers. Read skips delimiters preceding an integer or real,
         and stops reading the number input when a delimiter occurs.
 
         For text files, Read gets a 0 if the current position is at
         end-of-file, skipping delimiters.
 
         If the input does not match the format of the variable
         receiving the value, an I/O error occurs.
 
      3. String input is delimited by an end-of-line or end-of-file,
         and the string that is read does not include the delimiter.
         Read moves the current position to the delimiter. A subsequent
         Read from a text file would get a zero-length string. It is
         better to use Readln to get string input. Read checks the
         length of the string variable and truncates the input if
         necessary.
 
    For text files, Read treats CTRL+Z as an end-of-file. However, if
    the Crt unit is used, the effect of reading a CTRL+Z changes.
    CheckEOF is a Boolean variable defined in the Crt unit. When
    CheckEOF is False (default), a CTRL+Z is treated as any other
    input. When set to True, a CTRL+Z causes the end of input.
 
    If Read is called for a typed file when the current position is at
    end-of-file, an I/O error occurs.
 
    If Read is called for a text file opened for writing with the
    Append or Rewrite procedures, an I/O error occurs.
 
    If file_variable is not associated with a file or if the file is
    not open when Read is called, an I/O error occurs.
 
    To prevent a program from halting with a run-time error when an
    I/O error occurs, turn off I/O checking with {$I-} and check the
    return value of the IOResult function.