Function SCIPgetNlhdlrExprDataNonlinear 

pub unsafe extern "C" fn SCIPgetNlhdlrExprDataNonlinear(
    nlhdlr: *mut SCIP_NLHDLR,
    expr: *mut SCIP_EXPR,
) -> *mut SCIP_NLHDLREXPRDATA

gives expression data that a given nonlinear handler stored in an expression

Returns NULL if expr has not been detected by nlhdlr or nlhdlr did not store data.