Function SCIPchgCharParam 

pub unsafe extern "C" fn SCIPchgCharParam(
    scip: *mut SCIP,
    param: *mut SCIP_PARAM,
    value: c_char,
) -> SCIP_RETCODE

changes the value of an existing char parameter

@return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref SCIP_Retcode “SCIP_RETCODE” for a complete list of error codes.