Microsoft KB Archive/41203

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PRB: getch Does Not Behave as Expected with ALT+Q and ALT+R

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Q41203

5.10 6.00 6.00a 6.00ax 7.00 | 1.00 1.50 MS-DOS | WINDOWS kbprg kbprb -- The information in this article applies to: - The C Run-time (CRT), included with: - Microsoft C for MS-DOS, versions 5.1, 6.0, 6.0a, and 6.0ax - Microsoft C/C++ for MS-DOS, version 7.0 - Microsoft Visual C++ for Windows, versiona 1.0 and 1.5 -- SYMPTOMS ======== The program accepts all keyboard inputs, but does not behave as expected if the input is ALT+Q or ALT+R. CAUSE ===== This is not a problem with the Microsoft C Optimizing Compiler run-time function getch. The problem is caused because MS-DOS uses these two key combinations for other control purposes. MORE INFORMATION ================ In this case, the second scancode of ALT+Q is 16 and the second scancode of ALT+R is 19 (both decimal). MS-DOS uses scancode 16 to mean &quot;echo subsequent output to the printer&quot; and scancode 19 to mean &quot;pause output.&quot; These are equivalent to CTRL+P and CTRL+S. When a printer is not connected to the computer, the PRINT SCREEN key must wait for time-out. For the SCREEN PAUSE key, another key must be pressed to activate the screen again. Additional reference words: 5.10 6.00 6.00a 6.00ax 7.00 1.00 1.50 KBCategory: kbprg kbprb KBSubcategory: CRTIss

Keywords : kb16bitonly

Issue type :

Technology : kbVCsearch kbAudDeveloper kbCRT