Function SCIPcompareExpr 

pub unsafe extern "C" fn SCIPcompareExpr(
    scip: *mut SCIP,
    expr1: *mut SCIP_EXPR,
    expr2: *mut SCIP_EXPR,
) -> c_int

compare expressions @return -1, 0 or 1 if expr1 <, =, > expr2, respectively @note The given expressions are assumed to be simplified.