Function SCIPmultihashSafeInsert 

pub unsafe extern "C" fn SCIPmultihashSafeInsert(
    multihash: *mut SCIP_MULTIHASH,
    element: *mut c_void,
) -> SCIP_RETCODE

inserts element in multihash table (multiple insertion of same element is checked and results in an error)

@note A pointer to a multihashlist returned by SCIPmultihashRetrieveNext() might get invalid when adding a new element to the multihash table, due to dynamic resizing.