>>= Operator (Visual Basic)
Updated: August 2012
Performs an arithmetic right shift on the value of a variable or property and assigns the result back to the variable or property.
The element on the left side of the >>= operator can be a simple scalar variable, a property, or an element of an array. The variable or property cannot be ReadOnly (Visual Basic). The >>= operator assigns the value on its right to the variable or property on its left.
Arithmetic shifts are not circular, which means the bits shifted off one end of the result are not reintroduced at the other end. In an arithmetic right shift, the bits shifted beyond the rightmost bit position are discarded, and the leftmost bit is propagated into the bit positions vacated at the left. This means that if variableorproperty has a negative value, the vacated positions are set to one. If variableorproperty is positive, or if its data type is an unsigned type, the vacated positions are set to zero.
The >> Operator (Visual Basic) can be overloaded, which means that a class or structure can redefine its behavior when an operand has the type of that class or structure. Overloading the >> operator affects the behavior of the >>= operator. If your code uses >>= on a class or structure that overloads >>, be sure you understand its redefined behavior. For more information, see Operator Procedures (Visual Basic).