Reference for package '#rtl'

THandleStream

[Properties (by Name)][Methods (by Name)][Events (by Name)]

Base class for streams that are identified by an OS handle.

Declaration

Source position: classesh.inc line 1165

Type
  THandleStream = class (TStream)
  private
    FHandle : THandle;
  protected
    procedure SetSize(NewSize: LongInt);  Override;
    procedure SetSize(const NewSize: Int64);  Override;
  public
    constructor Create(AHandle: THandle);
    function Read(var Buffer; Count: LongInt) : LongInt;  Override;
    function Write(const Buffer; Count: LongInt) : LongInt;  Override;
    function Seek(const Offset: Int64; Origin: TSeekOrigin) : Int64
                 ;  Override;
    Handle : THandle;
  end
  ;

Description

THandleStream is an abstract descendant of the TStream class that provides methods for a stream to handle all reading and writing to and from a handle, provided by the underlying OS. To this end, it overrides the Read and Write methods of TStream.

Remark

ThandleStream does not obtain a handle from the OS by itself, it just handles reading and writing to such a handle by wrapping the system calls for reading and writing; Descendant classes should obtain a handle from the OS by themselves and pass it on in the inherited constructor. Contrary to Delphi, no seek is implemented for THandleStream, since pipes and sockets do not support this. The seek is implemented in descendant methods that support it. !!!

Members

Member Type Visibility Description
Create Method public Create a handlestream from an OS Handle.
FHandle Field private
Handle Property public The OS handle of the stream.
Read Method public Overrides standard read method.
Seek Method public Overrides the Seek method.
SetSize Method protected
Write Method public Overrides standard write method.

Inheritance

Class Description
THandleStream Base class for streams that are identified by an OS handle.

See also

Name Description
TFileStream Stream that stores its data in a named file on disk.
THandle Type to manage streams.
THandle Type to manage streams.
TStream Base class for streams.