pub unsafe extern "C" fn CPXsetincumbentcallbackfunc(
env: CPXENVptr,
incumbentcallback: Option<unsafe extern "C" fn(xenv: CPXCENVptr, cbdata: *mut c_void, wherefrom: c_int, cbhandle: *mut c_void, objval: f64, x: *mut f64, isfeas_p: *mut c_int, useraction_p: *mut c_int) -> c_int>,
cbhandle: *mut c_void,
) -> c_int