VBA VBA Run-Time Errors Run-time error '20': Resume without error
Example
Incorrect code
Sub DoSomething()
On Error GoTo CleanFail
DoSomethingElse
CleanFail:
Debug.Print Err.Number
Resume Next
End Sub
Why doesn't this work?
If the DoSomethingElse procedure raises an error, execution jumps to the CleanFail line label, prints the error number, and the Resume Next instruction jumps back to the instruction that immediately follows the line where the error occurred, which in this case is the Debug.Print instruction: the error-handling subroutine is executing without an error context, and when the Resume Next instruction is reached, run-time error 20 is raised because there is nowhere to resume to.
Correct Code
Sub DoSomething()
On Error GoTo CleanFail
DoSomethingElse
Exit Sub
CleanFail:
Debug.Print Err.Number
Resume Next
End Sub
Why does this work?
By introducing an Exit Sub instruction before the CleanFail line label, we have segregated the CleanFail error-handling subroutine from the rest of the procedure body - the only way to execute the error-handling subroutine is via an On Error jump; therefore, no execution path reaches the Resume instruction outside of an error context, which avoids run-time error 20.
Other notes
This is very similar to Run-time error '3': Return without GoSub; in both situations, the solution is to ensure that the normal execution path cannot enter a sub-routine (identified by a line label) without an explicit jump (assuming On Error GoTo is considered an explicit jump).
