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Q22135: INFO: Windows DEVICEDATA Escape Usage

Article: Q22135
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.1
Operating System(s): 
Keyword(s): kb16bitonly kbOSWin310 _IK kbOSWin300 kbSDKWin16
Last Modified: 02-JUL-1999

3.00 3.10
WINDOWS
kbprg

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The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) 3.1 
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SUMMARY
=======

The following provides information about the usage of the DEVICEDATA escape.

MORE INFORMATION
================

The term "#define DEVICEDATA 19" was previously called PASSTHROUGH; however, it
was later renamed. Using the DEVICEDATA escape, which is essentially a
"pass-through" to the device, will make an application absolutely device
dependent.

The primary use of the DEVICEDATA escape is to download information that needs to
be in the printer (that is, information that should be there, however, the
programmer knows is not there) or to set the printer state. The DEVICEDATA
escape will not interact with the GDI in a reasonable way; however, it allows
device-driver writers to provide escapes directly into a printer for functions
supported there. In particular, if the state in a printer is set to something
other than what GDI thinks it to be, the results could be unpredictable. For
example, a simple dump of text strings could be sent to a device. However, the
programmer must be sure that the printer is in text mode (that is, not in
graphics mode) before the programmer attempts this procedure.

A better way to perform a "quick and dirty" print is to set the requested print
quality to Draft. Time-conscious drivers would probably use intrinsic fonts for
draft-quality printing (no assertion has been made that there are any drivers
out there that actually do this; it is part of the semantics of draft-quality
printing).

To summarize this information, the DEVICEDATA escape provides a simple way to
send a string of bytes to a device; however, it does not provide a simple way to
print to the device. It is device-dependent as to whether those bytes get
printed, are interpreted as a downloaded font, reset printer characteristics,
and so on. The DEVICEDATA escape should not be considered a substitute for using
the GDI interface. For these reasons, Microsoft recommends that this escape
never be used by well-behaved applications.

Additional query words: 3.00 3.10

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Keywords          : kb16bitonly kbOSWin310 _IK kbOSWin300 kbSDKWin16 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310
Version           : WINDOWS:3.1
Issue type        : kbinfo

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