The SIGNAL keyword was reserved for OS/2 systems (protected mode). See the example for more information about how and why it is used.


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:: [[ON]] SIGNAL(number) [[GOSUB]] line

:: SIGNAL(number) [[ON]]


*'''[[Keywords currently not supported by QB64|Currently NOT supported in QB64!]]'''
* It will only work with compiler 6.00 and 6.00b and Basic PDS 7.00 when compiling in protected mode under OS/2. In all other situations, a SIGNAL statement results in an "Advanced feature unavailable" error message. 


''Example:''
{{CodeStart}}
'' ''
{{Cl|PRINT}} "This program traps CTRL+BREAK in OS/2. Try it."
{{Cl|ON}} SIGNAL(4) {{Cl|GOSUB}} trap
{{Cl|SIGNAL}}(4) {{Cl|ON}}
10 a$ = {{Cl|INKEY$}}

{{Cl|IF...THEN|IF}} a$ = "" {{Cl|THEN}} {{Cl|GOTO}} 10
{{Cl|END}}
trap:
{{Cl|PRINT}} "CTRL+BREAK trapped. Press any key to quit"
{{Cl|RETURN}} '' ''

{{CodeEnd}}


''Output:'' It returns the following when Ctrl-Break is pressed
{{OutputStart}}
This program traps CTRL+BREAK in OS/2. Try it.

CTRL+BREAK trapped. Press any key to quit
{{OutputEnd}}

''Error message in QB4.5 if not using OS 2:''

{{OutputStart}}
Advanced feature unavailable
{{OutputEnd}}


''Source:'' Microsoft KB41389 [[http://support.microsoft.com/kb/41389]]


''See also:'' 
* [[ON KEY (n)]]


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