The $BITPACKING directive tells the compiler whether it should use bitpacking or not when it encounters the packed keyword for a structured type. The possible values are ON and OFF. If ON, then the compiler will bitpack structures when it encounters the Packed keyword.
In the following example, the TMyRecord record will be bitpacked:
{$BITPACKING ON}
Type
TMyRecord = packed record
B1,B2,B3,B4 : Boolean;
end;
Note that:
The $BITPACKING directive is ignored in macpas mode, where packed records are always bitpacked.
The bitpacked keyword can always be used to force bitwise packing, regardless of the value of the $BITPACKING directive, and regardless of the mode.