ID Number: Q67675
3.00 3.10
WINDOWS
Summary:
Windows real and standard modes do not provide an interface for
standard MS-DOS (non-Windows) applications to access the Windows
clipboard. However, in Windows enhanced mode, access is provided
through the INT 2fh interface. This article discusses various methods
that may be used to simulate clipboard access in real and standard
modes and documents the INT 2fh interface for enhanced mode.
More Information:
Under Windows real and standard modes, it is possible to simulate
programmatic access to the contents of the clipboard by a standard
MS-DOS application. One possible method is to create a Windows
application that places the contents of the Windows clipboard into a
file. The MS-DOS application would check for the existence of the file
saved from the Windows application. When the file exists, the MS-DOS
application can read the contents, eliminating the necessity for
direct user intervention on behalf of the MS-DOS application.
Only textual information can be retrieved from the clipboard by a
standard MS-DOS application. This is done using the Edit Paste
hierarchical system menu combination in Windows enhanced mode that is
available when the MS-DOS application is windowed.
In Windows real or standard modes, a Paste option can be selected
directly from the system menu only when the MS-DOS application is
represented by an icon ("iconic"), giving the user access to its
system menu. When Paste is selected, Windows will restore the MS-DOS
application to full screen and paste the contents of the clipboard
where the cursor is located in the MS-DOS application. MS-DOS
applications can be made iconic in real and standard modes through an
ALT+TAB keystroke.
Placing information into the clipboard can be done though the use of
the PRINT SCREEN or ALT+PRINT SCREEN keystrokes, each of which copies
a full screen into the clipboard.
Copying information to the Windows clipboard can be done in Windows
enhanced mode using the Edit Mark and Edit Copy system menu commands.
More information on user control of the Windows Clipboard can be found
on pages 440-490 in the "Microsoft Windows User's Guide," Chapter 12.
The remainder of this article documents the INT 2fh interface to the
clipboard, available in Windows enhanced mode.
Note: The Windows functions RegisterClipboardFormat() and
EnumClipboardFormats() are not supported.
Function Call Definitions
-------------------------
Name IdentifyWinOldApVersion()
Parameters AX = 1700H
Return Values AX == 1700H: Clipboard functions not available
<> 1700H: AL = Major version number
AH = Minor version number
Name OpenClipboard()
Parameters AX = 1701H
Return Values AX == 0: Clipboard already open
<> 0: Clipboard opened
Name EmptyClipboard()
Parameters AX = 1702H
Return Values AX == 0: Error occurred
<> 0: OK, Clipboard emptied
Name SetClipboardData()
Parameters AX = 1703H
DX = WinOldAp-Supported Clipboard format
ES:BX = Pointer to data
SI:CX = Size of data in bytes
Return Values AX == 0: Error occurred
<> 0: OK. Data copied into allocated memory.
Note The MS-DOS application should call the
ClipboardCompact() function prior to this to determine
if the data can be accommodated in memory.
Name GetClipboardDataSize()
Parameters AX = 1704H
DX = WinOldAp-Supported Clipboard format
Return Values DX:AX == Size of the data in bytes, including any
headers.
== 0 If data in this format is not in the clipboard.
Name GetClipboardData()
Parameters AX = 1705H
DX = WinOldAp-Supported Clipboard format
ES:BX = Pointer to data buffer to hold data
Return Values AX == 0: Error occurred (or data in this format is not
in the clipboard)
<> 0: OK
Note This call should be preceded by a
GetClipBoardDataSize() call to find out how much memory
is required for the buffer. No checking is performed, the
caller must ensure that the buffer is big enough;
otherwise, some of the callers code or data may be
overwritten.
Name CloseClipboard()
Parameters AX = 1708H
Return Values AX == 0: Error occurred
<> 0: OK
Name ClipboardCompact()
Parameters AX = 1709H
SI:CX = Desired memory size in bytes.
Return Values DX:AX == Number of bytes of largest block of free memory.
== 0 if error or no memory
Notes The MS-DOS application is responsible for including the
size of any headers in the desired memory size.
Name GetDeviceCaps()
Parameters AX = 170AH
DX = GDI information index
Return Values AX == integer value of desired item
== 0 if error
Notes The implied hDC for this call will be for the display.
Supported Clipboard Formats
---------------------------
The following Windows clipboard formats are supported:
CF_TEXT = 1
CF_BITMAP = 2 ; See structures section
CF_OEMTEXT = 7
CF_DSPTEXT = 81h
CF_DSPBITMAP = 82h
Note: Since the RegisterClipboardFormat() and EnumClipboardFormats()
functions are not available at this time, the use of private
clipboard formats is not supported.
Structures
----------
These structures mimic the actual Windows structures with one major
difference: instead of including a handle or pointer to other memory
containing the actual data, the data follows the structure. The
structure information now behaves like a header prefacing the data.
Bitmap structure:
bmType DW ? ; Always 0
bmWidth DW ? ; Width of bitmap in pixels
bmHeight DW ? ; Height of bitmap in raster lines
bmWidthBytes DW ? ; Bytes/raster line
bmPlanes DB ? ; Number of color planes in the bitmap
bmBitsPixel DB ? ; Number of adj color bits to def pixel
bmBits DQ ? ; Points to byte following bmHigDim
bmWidDim DW ? ; Width of bitmap in 0.1 mm units
bmHigDim DW ? ; Height of bitmap in 0.1 mm units
BitmapData nBytes ; The actual data