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ReadSByte  
Method  
Reads the next signed byte from the current stream
BinaryReader Class
System.IO NameSpace
CF1.  Function ReadSByte ( ) : SByte;
CF : Methods with this mark are Compact Framework Compatible
Description
If the current stream has not been exhausted, the next byte is returned as a signed byte (value ranges from -128 to +127).
 
The stream position is updated accordingly.
Microsoft MSDN Links
System.IO
System.IO.BinaryReader
 
 
Reading a single signed byte at a time
program Project1;
{$APPTYPE CONSOLE}

uses
  System.IO;

var
  MyFileStream  : System.IO.FileStream;
  MyFileWriter  : System.IO.BinaryWriter;
  MyFileReader  : System.IO.BinaryReader;
  SignedByte    : SByte;

begin
  // Create and open our binary file as a stream
  MyFileStream := System.IO.File.Open('C:DelphiBasics.txt',
                                      System.IO.FileMode.Create);

  // Create a BinaryWriter to allow writing to this file
  MyFileWriter := System.IO.BinaryWriter.Create(MyFileStream);

  // Write to the file
  MyFileWriter.Write(12);
  MyFileWriter.Write(-34);
  MyFileWriter.Write('ABC');  // Chr(65) Chr(66) Chr(67)

  // Close the writer and the stream
  MyFileWriter.Close;
  MyFileStream.Close;

  // Reopen the stream for reading
  MyFileStream := System.IO.File.Open('C:DelphiBasics.txt',
                                      System.IO.FileMode.Open);

  // Create a BinaryReader to allow the file to be read back
  MyFileReader := System.IO.BinaryReader.Create(MyFileStream);

  // Display the file contents
  try
    // Infinite loop - we rely on the exception for file end
    while 1 = 1 do
    begin
      SignedByte := MyFileReader.ReadSByte;
      Console.WriteLine(SignedByte.ToString);
    end;
  except
    On E : EndOfStreamException do
      Console.WriteLine('File display completed');
  end;

  // Close the reader and the stream
  MyFileReader.Close;
  MyFileStream.Close;

  Console.Readline;
end.
Show full unit code
  12
  -34
  3
  65
  66
  67
  File display completed
 
 
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