From Free Pascal wiki
A TFileStream is a descendant of TStream that gets/stores its data from/to a file on disk. A TFileStream reads entire file data into memory and vice versa.
|fmCreate||65280||Creates a new file|
|fmOpenRead||0||opens a file for reading|
|fmOpenWrite||1||opens a file for writing|
|fmOpenReadWrite||2||opens a file for reading and writing|
|fmShareDenyWrite||32||prohibit writing if file is already opened|
read from file fnam.
function readstream( fnam: string ): string; var strm: TFileStream; n: longint; txt: string; begin txt := ''; strm := TFileStream.Create( fnam, fmOpenRead or fmShareDenyWrite ); try n := strm.Size; SetLength( txt, n ); strm.Read( txt, n ); finally FreeAndNil( strm ); end; result := txt; end;
Write txt to file fnam.
procedure writestream( fnam: string; txt: string ); var strm: TFileStream; n: longint; begin strm := TFileStream.Create( fnam, fmCreate ); n := Length( txt ); try strm.Position := 0; strm.Write( txt, n ); finally FreeAndNil( strm ); end; end;