BYREF (parameters)


Declaration specifier to explicitly pass a parameter by reference

Syntax:
Byref param as datatype

Usage:
[ declare ] { sub | function } proc_name ( Byref param as datatype )

Description:
Passes a variable by reference, that is its address, to a subroutine or function. When a variable is passed by reference, the contents of the variable can be changed by the target subroutine or function.

In -lang qb and -lang fblite dialects, Byref is the default parameter passing convention, unless Option ByVal is in effect.

Opposite of ByVal.

Note: A constant or a literal expression can also be passed to such a procedure (which gets by reference), but they are obviously not modifiable. In that case, the compiler passes by reference a temporary variable initialized with the constant or the literal expression.

Examples:
Dim MyVar As Integer

Sub ChangeVar(ByRef AVar As Integer)
    AVar = AVar + 1
End Sub

MyVar = 1
Print "MyVar: "; MyVar 'output = 1
ChangeVar MyVar
Print "MyVar: "; MyVar 'output = 2
Sleep
End


Dialect Differences:
Differences from QB:
See also:
Back to Procedures
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