Function SCIPensureRowprepSize 

pub unsafe extern "C" fn SCIPensureRowprepSize(
    scip: *mut SCIP,
    rowprep: *mut SCIP_ROWPREP,
    size: c_int,
) -> SCIP_RETCODE

ensures that rowprep has space for at least given number of additional terms

Useful when knowing in advance how many terms will be added.