On...Gosub
Calls a label based on an expression
On expression GoSub label1[, ...]
Branches to different labels depending on the value of expression. An expression value of 1 will branch to the first label, a value of 2 to the second, etc. If the value of expression is zero (0) or greater than the number of items in the list, execution continues on the next statement following the On...Gosub.
This statement behaves exactly like GoSub and execution may return to the statement following the On...Gosub using Return.
It is recommended that the structured Select Case conditional statement be used instead of On...Gosub.
Syntax
On expression GoSub label1[, ...]
Description
Branches to different labels depending on the value of expression. An expression value of 1 will branch to the first label, a value of 2 to the second, etc. If the value of expression is zero (0) or greater than the number of items in the list, execution continues on the next statement following the On...Gosub.
This statement behaves exactly like GoSub and execution may return to the statement following the On...Gosub using Return.
It is recommended that the structured Select Case conditional statement be used instead of On...Gosub.
Example
'' Compile with -lang qb
'$lang: "qb"
choice = 3
On choice GoSub labela, labelb, labelc
Print "Good bye."
End
labela:
Print "choice a"
Return
labelb:
Print "choice b"
Return
labelc:
Print "choice c"
Return
'$lang: "qb"
choice = 3
On choice GoSub labela, labelb, labelc
Print "Good bye."
End
labela:
Print "choice a"
Return
labelb:
Print "choice b"
Return
labelc:
Print "choice c"
Return
Dialect Differences
- Only available in the -lang qb and -lang fblite dialects.
- On Gosub support is disabled by default in the -lang fblite unless the Option Gosub statement is used.
Differences from QB
- FreeBASIC does not generate a run-time error if expression is negative or greater than 255.
See also