Function Statement
A function is a block of code which runs when it is called. A function is usually called in an expression.
You can pass data, known as parameters or arguments, into a function. You may pass a parameter by value or by reference. When by reference, modifications applied to the parameter in the function will be sent back to the calling code.
A function usually returns data as a result.
[Private | Public] Function Name[char] (argument1 [As Type][, argument2[char][,...]]) [As typename]
statements
[Exit Function]
statements
End Function
scope: Function default scope is Public. A Private scope denotes a module internal routine, not intended to be used from other modules.
name: Name of the subroutine to contain the value returned by the function.
arguments: Parameters to be passed to the subroutine.
argument fragment
{[Optional [ByRef|ByVal]]|ParamArray} argument {{As typename|char}[ = expression]|[()]As Variant}
Parameters
Optional: The argument is not mandatory.
ByRef: The argument is passed by reference. ByRef is the default.
ByVal: The argument is passed by value. Its value can be modified by the called routine.
char: Type declaration character.
typename: Primitive data type name. Library or module defined types can also be specified.
= expression: Specify a default value for the argument, matching its declared type. Optional is necessary for each argument specifying a default value.
ParamArray: Use ParamArray when the number of parameters is undetermined. A typical scenario is that of a Calc user-defined function. Using ParamArray should be limited to the last argument of a routine.
UsingParamArray or = expression require Option Compatible to be placed before the executable program code in a module.
When using Option VBASupport 1, Optional arguments with no default value (= expression) are initialized according to their data type, except if Variant.
Examples:
Sub ExampleExit
Dim sReturn As String
Dim sListArray(10) As String
Dim siStep As Single
For siStep = 0 To 10 ' Fill array with test data
sListArray(siStep) = chr$(siStep + 65)
MsgBox sListArray(siStep)
Next siStep
sReturn = LinSearch(sListArray(), "B")
Print sReturn
End Sub
Function LinSearch( sList(), sItem As String ) As Integer
Dim iCount As Integer
REM Linsearch searches a TextArray:sList() for a TextEntry:
REM Return value is the index of the entry or 0 (Null)
For iCount=1 To Ubound( sList() )
If sList( iCount ) = sItem Then
Exit for REM sItem found
End If
Next iCount
If iCount = Ubound( sList() ) Then iCount = 0
LinSearch = iCount
End Function