Microsoft KB Archive/82749

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Using LPT1.OS2, LPT1.DOS, or FILE: Ports When Printing

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Q82749

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The information in this article applies to:


 * Microsoft Windows versions 3.1, 3.11

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SUMMARY
In Microsoft Windows version 3.1, the LPT1.DOS printer port connection has exactly the same effect as typing LPT1.DOS (or LPT1.OS2) when printing to a FILE:. If you type LPT1.DOS (or LPT1.OS2), a message box asking &quot;Overwrite existing file?&quot; appears. Choose the Yes button to print. This message appears because MS-DOS assumes that the file LPT1.xxx (where xxx is any extension) always exists.

Note that the LPT1.OS2 or LPT1.DOS syntax is not required. It is included in Windows 3.1 for backward compatibility only. Using LPT1 (or typing LPT1 in the FILE: output file dialog box) has the same effect.

LPT2 and LPT3 connections behave similarly.

MORE INFORMATION
A problem in Windows 3.0 was corrected to allow binary files to be printed to LPT1.xxx-style ports. In Windows 3.0, the output was copied to the port using a command similar to the MS-DOS COPY command without the /B parameter, which would stop the output if a CTRL+Z (^Z) End-of- File (EOF) character was found in the output. The port is now written to in a raw mode, allowing binary data containing EOF characters to be written.

Additional query words: 3.10 3.11 binary EOF end-of-file /B

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Issue type :

Technology : kbWin3xSearch kbWin310 kbWin311