| Description |
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Count bytes from StartIndex are locked. This prevents other, concurrent processes writing to them.
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| | Notes | This is somewhat beyond Delphi Basics, so the example merely illustrates the syntax.
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| Microsoft MSDN Links |
System.IO
System.IO.FileStream
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| Illustrating the syntax |
program Project1;
{$APPTYPE CONSOLE}
uses
System.IO;
var
Stream : System.IO.FileStream;
i : Integer;
begin
// Open the file for writing
Stream := System.IO.FileStream.Create('C:\DelphiBasics.txt',
FileMode.Create);
// Write to the file
Stream.WriteByte(65); // Chr(65) = 'A'
Stream.WriteByte(66); // Chr(66) = 'B'
Stream.WriteByte(67); // Chr(67) = 'C'
Stream.WriteByte(68); // Chr(68) = 'D'
Stream.WriteByte(69); // Chr(69) = 'E'
// Lock the last 3 bytes for update
Stream.Lock(2, 3);
// Now any concurrent process will be unable to write to
// these last 3 bytes of the file.
// ... Run a concurrent process at this point
// Unlock the file
Stream.Unlock(2, 3);
// Close the stream
Stream.Close;
Console.Readline;
end.
| | Show full unit code |
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