359 lines
13 KiB
Plaintext
359 lines
13 KiB
Plaintext
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Turbo Vision 2.0 Programming Guide
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==================================
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This file contains information on material added to Turbo Vision
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2.0 after the Programming Guide had gone to press and also
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corrections to a few errors in the manual. We strongly suggest
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that you mark these corrections and changes in your manual for
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future reference.
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=============================================================
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Changes and additions to Chapter 19, "Turbo Vision Reference"
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CreateFindDialog function Editors
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Declaration function CreateFindDialog: PDialog;
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Function Constructs and returns a pointer to the
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standard text search dialog box used by
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StdEditorDialog. If you want to customize
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the simpler editor dialog boxes but still
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use the standard text search interface,
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your editor dialog box function should
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execute the dialog box returned by
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CreateFindDialog for a Dialog parameter
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of edFind.
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See also EditorDialog variable, edXXXX constants,
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StdEditorDialog function
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CreateReplaceDialog function Editors
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Declaration function CreateReplaceDialog: PDialog;
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Function Constructs and returns a pointer to the
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standard text search-and-replace dialog
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box used by StdEditorDialog. If you want
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to customize the simpler editor dialog
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boxes but still use the standard text
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search interface, your editor dialog box
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function should execute the dialog box
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returned by CreateReplaceDialog for a
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Dialog parameter of edReplace.
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See also EditorDialog variable, edXXXX constants,
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StdEditorDialog function
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=============================================================
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FailSysErrors variable Drivers
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Declaration FailSysErrors: Boolean = False;
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If True, causes the system error handler
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to behave as if the user had responded to
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a system error message by pressing Esc.
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Normally, the system error handler
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displays a message on the last line of
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the screen and waits for user input.
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Setting FailSysErrors to True causes the
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system error handler to bypass the
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message and user prompt, and just return
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as if the DOS call that produced the
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error failed.
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See also SysErrorFunc variable
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=============================================================
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GetCtrlChar function Drivers
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Declaration function GetCtrlChar(KeyCode: Word):
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Char;
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Function Returns the character, Ch, for which
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Ctrl+Ch produces the 2-byte scan code
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given by the argument KeyCode. Gives the
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reverse mapping to GetCtrlCode.
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See also GetCtrlCode
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=============================================================
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GetCtrlCode function Drivers
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Declaration function GetCtrlCode(Ch: Char): Word;
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Function Returns the 2-byte scan code (keycode)
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corresponding to Ctrl+Ch. This function
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gives the reverse mapping to GetCtrlChar.
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See also GetCtrlChar
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=============================================================
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GetShiftState function Drivers
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Declaration function GetShiftState: Byte;
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Function Returns a byte containing the current
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Shift key state, as reported by DOS. The
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return value contains a combination of
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the kbXXXX constants for shift states.
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You should call GetShiftState instead of
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checking the ShiftState variable
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directly. ShiftState is not guaranteed to
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be valid in protected mode, but
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GetShiftState returns the correct value
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in either real or protected mode.
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See also kbXXXX constants
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=============================================================
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RegisterMenus procedure Menus
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Declaration procedure RegisterMenus;
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Function Calls RegisterType for each of the object
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types defined in the Menus unit:
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TMenuBar, TMenuBox, TMenuPopup, and
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TStatusLine. After calling RegisterMenus,
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your application can read or write any of
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those types with streams.
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See also RegisterType procedure
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=============================================================
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RegisterViews procedure Views
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Declaration procedure RegisterViews;
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Function Calls RegisterType for each of the object
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types defined in the Views unit: TView,
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TFrame, TScrollBar, TScroller,
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TListViewer, TGroup, and TWindow. After
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calling RegisterViews, your application
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can read or write any of those types with
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streams.
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See also RegisterType procedure
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=============================================================
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ShiftState variable Drivers
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=============================================================
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Although this variable exists to maintain
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compatibility with version 1.0, you
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should not check ShiftState directly.
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Rather, you should call GetShiftState,
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which returns a valid set of shift state
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flags in either real or protected mode.
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TDesktop App
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TDesktop has two additional methods not
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documented.
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Methods =========================================
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Load constructor Load(var S: TStream);
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Constructs and loads a desktop object
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from the stream S by first calling the
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Load constructor inherited from TGroup,
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then calling GetSubViewPtr to set up the
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Background field, then reading the
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TileColumnsFirst field.
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See also: TGroup.Load,
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TGroup.GetSubViewPtr
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Store procedure Store(var S: TStream);
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Writes the desktop object to the stream S
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by first calling the Store method
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inherited from TGroup, then calling
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PutSubViewPtr to store the Background
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field, then writing the value of
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TileColumnsFirst.
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See also: TGroup.Store,
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TGroup.PutSubViewPtr
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=============================================================
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TMemoryStream Objects
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TMemoryStream implements a stream in heap
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memory.
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The mechanics of using memory streams are
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simple. You construct a memory stream,
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specifying its initial size and a block
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size. The memory stream allocates as many
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blocks on the heap as needed to meet the
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initial size. Bytes stored on the stream
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are not guaranteed to be in contiguous
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memory locations unless the stream
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consists of a single block.
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Once you construct the stream, you use it
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like any other. Writing beyond the end of
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the stream causes the stream to grow in
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increments of the initial block size, up
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to a maximum of 16,384 blocks.
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Changing the size of a memory stream by
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enlarging or truncating could seriously
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fragment your heap. Try to set the
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initial size and block size of the stream
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to reasonable values to minimize
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individual allocations.
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Fields =========================================
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BlockSize BlockSize: Integer;
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The size of each block allocated to the
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memory stream.
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CurSeg CurSeg: Integer;
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Holds the segment part of the address of
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the block that contains the current
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stream position.
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Position Position: Longint;
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The position of the stream in bytes. The
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first position is 0.
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SegCount SegCount: Integer;
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The number of blocks currently allocated
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to the memory stream.
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SegList SegList: PWordArray;
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Contains the list of segment parts used
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by each allocated block. The entries
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0..SegCount-1 contain valid segments.
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Size Size: Longint;
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The size of the stream in bytes.
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Methods =========================================
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Init constructor Init(ALimit: Longint;
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ABlockSize: Word);
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Constructs a memory stream object by
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first calling the Init constructor
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inherited from TStream, then allocates
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enough blocks of size ABlockSize to
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collectively contain ALimit bytes. Sets
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BlockSize to ABlockSize.
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See also: TStream.Init
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Done destructor Done; virtual;
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Disposes of the memory stream object by
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disposing of the memory allocated to the
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stream, then calling the Done destructor
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inherited from TStream.
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See also: TStream.Done
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GetPos function GetPos: Longint; virtual;
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Returns the stream's current position.
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The first position is 0.
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GetSize function GetSize: Longint; virtual;
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Returns the size of the stream in bytes.
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Read procedure Read(var Buf; Count: Word);
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virtual;
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Reads Count bytes from the stream,
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starting at the current position, into
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the buffer Buf.
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Seek procedure Seek(Pos: Longint); virtual;
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Sets the current position to Pos bytes
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from the start of the stream. The first
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position is 0.
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Truncate procedure Truncate; virtual;
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Deletes all data on the stream from the
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current position to the end. Sets the
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current position to the new end of the
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stream.
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Write procedure Write(var Buf; Count: Word);
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virtual;
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Writes Count bytes from the buffer Buf to
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the stream, starting at the current
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position.
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=============================================================
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TStringList Objects
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=============================================================
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In the example code in the Load
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constructor description, TBufStream
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should be PBufStream.
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=============================================================
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TStrListMaker Objects
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=============================================================
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In the example code in the description of
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how to use the string list maker,
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TBufStream should be PBufStream.
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