Resuming execution in a calling procedure
On Error Resume Next has a special meaning in handling an error that occurred in a lesser procedure. LotusScript® considers the procedure call to be the statement that caused the error; so "Next" refers to the next statement in the calling procedure.
For example:
Sub TestHand
Dim num As Single
num! = 1
Print num! / 0
End Sub
Sub SuperHand
On Error Resume Next
Call TestHand()
' When control returns to SuperHand upon an error
' in TestHand, execution continues at this Print statement.
Print "Continuing after calling sub TestHand."
Exit Sub
End Sub
Call SuperHand()
' Output:
' Continuing after calling sub TestHand.
Similarly, when the statement Resume Next appears within an error-handling routine for an error that occurred in a lower-level procedure, "Next" refers to the next statement in the calling procedure.
The statement Resume 0, or simply Resume, in an error-handling routine means to re-execute the line where the error occurs, even if that line is in a called procedure.
For example:
' The sub SuperHand calls the sub TestHand with an argument
' of 0, which produces an error. The error is handled by an
' error-handling routine in the caller, the sub SuperHand.
' Handling the error includes resetting the call argument
' to 1, and then calling TestHand with this argument. On the
' second call no error occurs.
Sub TestHand(num As Integer)
Dim num2 As Single
If num <> 0 GoTo ProcPo Print "Call argument to sub" & _
"TestHand is 0; will generate error."
' There's no error-handling routine in sub TestHand for
' division-by-zero, so control returns to the calling sub
' SuperHand when the next statement is executed.
num2! = num% / 0
' This Print statement is not executed at all.
Print "Continue here after division-by-zero error?"
Exit Sub
' Come here if call argument is nonzero.
ProcPos:
Print "Call argument to sub TestHand is nonzero" & _
" (no error)."
Exit Sub
End Sub
Sub SuperHand
Dim numIn As Integer
' A division-by-zero error not handled in sub TestHand
' is handled by the error-handling routine at DivZero.
On Error GoTo DivZero
Call TestHand(numIn%)
Exit Sub
DivZero:
Print "Handling division-by-zero error."
numIn% = 1
' Re-execute the statement that caused the error
' being handled. This will be the statement Call
' TestHand(numIn%). The call argument is now 1.
Resume 0
End Sub
Call SuperHand()
' Output:
' Call argument to sub TestHand is 0; will generate error.
' Handling division-by-zero error.
' Call argument to sub TestHand is nonzero (no error).