Seek

Moves the current position of a file to a specified component.

Declaration

procedure Seek(var F; N: Longint);

Target

Windows, Real, Protected

Remarks

F is any file variable type except text, and N is an expression of type Longint. The current file position of F is moved to component number N. The number of the first component of a file is 0. To expand a file, you can seek one component beyond the last component; that is, the statement Seek(F, FileSize(F)) moves the current file position to the end of the file.

With {$I-}, IOResult returns 0 if the operation was successful. Otherwise, it returns a nonzero error code.

Restrictions

• Cannot be used on text files.
• File must be open.

See Also

FilePos

Sample Code

{FilePos.PAS}
{Sample code for the FilePos and FileSize functions, and the Seek procedure.}

{ For Windows: }
{ uses WinCrt; }

var
  f: file of Byte;
  size : Longint;
begin
  { Get file name from command line }
  Assign(f, ParamStr(1));
  Reset(f);
  size := FileSize(f);
  Writeln('File size in bytes: ',size);
  Writeln('Seeking halfway into file...');
  Seek(f,size div 2);
  Writeln('Position is now ',FilePos(f));
  Close(f);
end.