How to embed an error code in a standard function return
I have read many accounts in various books and articles about how it would be nice to be able to return an error code with every function return.
It's fairly easy to achieve this. Simply create a User-Defined-Type (or class) called tReturn (or whatever) in a global module (assuming the use of a UDT).
'---------------------------------------------
Type tReturn
Value as Variant
Error as Integer
End Type
'---------------------------------------------
Creating a class (which I personally prefer utilizing in my own code) allows for fairly sophisticated error handling by embedding functions within the class to resolve the errors without needing to stick alot of error-handling code all over the place.
Usage
Make each function of type tReturn.
'---------------------------------------------
Public Function MyFunc(arg1, arg2) as tReturn
'---------------------------------------------
When coding the function body, if an error occurs simply assign a non-zero value to the ".Error" item in the return value
'---------------------------------------------
Public Function MyFunc(arg1, arg2) as tReturn
...
MyFunc.Error = 5 'Some Error
(or)
MyFunc.Error = Err
...
End Function
'---------------------------------------------
This way, you can always tell if an error has occured by checking the existence of an error in the return value
'---------------------------------------------
Dim MyReturn as tReturn
...
MyReturn = MyFunc(3,8)
If Not MyReturn.Error Then
nSomeVariable = MyReturn.Value
End If
...
'---------------------------------------------
If you create tRetrun as a class (cReturn or whatever), you can make .Value as the default property and code it this way:
'---------------------------------------------
Dim MyReturn as New cReturn
...
MyReturn = MyFunc(3,8)
If Not MyReturn.Error Then
nSomeVariable = MyReturn
End If
...
'---------------------------------------------
Special Instructions
This code originally appeared on AndreaVB.com, and has been republished here with the permission of Andrea Tincani.
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