ID Number: Q41203
5.10 6.00 6.00a 6.00ax 7.00
MS-DOS
Summary:
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 "echo subsequent output to the printer" and scancode 19 to mean
"pause output." 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