| Description |
The Seek procedure moves the current record position in an open binary file given by FileHandle to a new position RecordNumber.
The file must have been assigned with AssignFile and opened with Reset or ReWrite.
For untyped files, the record size is set with the Reset or ReWrite routine used.
For typed files, the record size is SizeOf the file type.
The first record in a file is record 0.
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| Notes |
Use SeekEoln or SeekEof to move the file pointer on a text file.
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| Related commands |
| Eof |
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Returns true if a file opened with Reset is at the end |
| Eoln |
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Returns true if the current text file is pointing at a line end |
| File |
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Defines a typed or untyped file |
| FilePos |
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Gives the file position in a binary or text file |
| SeekEoln |
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Skip to the end of the current line or file |
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| Example code : Repositioning in a Word type file |
// Full Unit code.
// -----------------------------------------------------------
// You must store this code in a unit called Unit1 with a form
// called Form1 that has an OnCreate event called FormCreate.
unit Unit1;
interface
uses
// The System unit does not need to be defined
SysUtils,
Forms, Dialogs;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm} // Include form definitions
procedure TForm1.FormCreate(Sender: TObject);
var
myWord, myWord1, myWord2, myWord3, myWord4 : Word;
myFile : File of Word;
begin
// Try to open the Test.cus binary file in write only mode
AssignFile(myFile, 'Test.cus');
ReWrite(myFile);
// Write a few lines of Word data to the file
myWord1 := 12;
myWord2 := 34;
myWord3 := 56;
myWord4 := 78;
Write(myFile, myWord1, myWord2, myWord3, myWord4);
// Close the file
CloseFile(myFile);
// Reopen the file for read only purposes
FileMode := fmOpenRead;
Reset(myFile);
// Seek (move) to the start of the 3rd record
Seek(myFile, 2); // Records start from 0
// Show this record
Read(myFile, myWord);
ShowMessage('Record 3 = '+IntToStr(myWord));
// Close the file
CloseFile(myFile);
end;
end.
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| Hide full unit code |
Record 3 = 56
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