This article was previously published under Q189579
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The F11 and F12 function keys do not work or generate extended charactersin MS-DOS applications running under Windows NT.
A program compiled or built using the 32-bit compiler is able to read allthe function keys and to return the right values of the scan codes. Whencompiled or built using the 16-bit compiler, the same program returns theright values for the function keys F1 through F10, but does not returnanything for F11 and F12.
To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
152734 How to Obtain the Latest Windows NT 4.0 Service Pack
Microsoft has confirmed that this is a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.
To read extended characters from an application, two consecutive calls toGETCH() are required:
The first call returns a value indicating that the key is an extended character.
The second call returns the actual key code (scan code).