Function SCIPgetNlpiSolverPointer 

pub unsafe extern "C" fn SCIPgetNlpiSolverPointer(
    scip: *mut SCIP,
    nlpi: *mut SCIP_NLPI,
    problem: *mut SCIP_NLPIPROBLEM,
) -> *mut c_void

gets internal pointer to NLP solver

Depending on the solver interface, a solver pointer may exist for every NLP problem instance. For this case, a NLPI problem can be passed in as well.