Exceptions/Catch an exception thrown in a nested call: Difference between revisions

=={{header|FreeBASIC}}==

FreeBASIC does not support exceptions or the Try/Catch/Finally statement, as such. However, you can use the Err() function, together with an If (or Switch) statement, to provide somewhat similar functionality:

<lang freebasic>' FB 1.05.0 Win64

Enum ErrorTypes

U0 = 1000

U1

End Enum

Function errorName(ex As ErrorTypes) As String

Select Case As Const ex

Case U0

Return "U0"

Case U1

Return "U1"

End Select

End Function

Sub catchError(ex As ErrorTypes)

Dim e As Integer = Err '' cache the error number

If e = ex Then

Print "Error "; errorName(ex); ", number"; ex; " caught"

End If

End Sub

Sub baz()

Static As Integer timesCalled = 0 '' persisted between procedure calls

timesCalled += 1

If timesCalled = 1 Then

err = U0

Else

err = U1

End if

End Sub

Sub bar()

baz

End Sub

Sub foo()

bar

catchError(U0) '' not interested in U1, assumed non-fatal

bar

catchError(U0)

End Sub

Foo

Print

Print "Press any key to quit"

Sleep</lang>

{{out}}

<pre>

Error U0, number 1000 caught

</pre>