Function SCIPexprGetActivityTag 

pub unsafe extern "C" fn SCIPexprGetActivityTag(
    expr: *mut SCIP_EXPR,
) -> c_longlong

returns the tag associated with the activity of the expression

It can depend on the owner of the expression how to interpret this tag. SCIPevalExprActivity() compares with stat->domchgcount.

@see SCIPevalExprActivity