Function SCIProwExactChgCoef 

pub unsafe extern "C" fn SCIProwExactChgCoef(
    row: *mut SCIP_ROWEXACT,
    blkmem: *mut BMS_BLKMEM,
    set: *mut SCIP_SET,
    eventqueue: *mut SCIP_EVENTQUEUE,
    lpexact: *mut SCIP_LPEXACT,
    col: *mut SCIP_COLEXACT,
    val: *mut SCIP_RATIONAL,
) -> SCIP_RETCODE

changes or adds a coefficient to an LP row