TheAPIchangesshouldprovidebothsourceandbinary()forprogramswrittentotheoriginalAPI.Thatis,existingprogrambinariesshouldcontinuetooperatewhenrunonasystemsupportingthenewAPI.Inaddition,existing(_______)thatarere-compiledandrunonasystemsupportingthenewAPIshouldcontinuetooperate.Simplyput,theAP()formulticastreceiversthatspecifysourcefiltersshouldnotbreakexistingprograms.ThechangestotheAPIshouldbeassmallaspossibleinordertosimplicitythetaskofconvertingexisting()receiverapplicationstousesourcefilters.Applicationsshouldbeabletodeletewhenthenew()filterAPIsareunavailable(e.g.,callsfailwiththeENOTSUPPerror)andreactgracefully(e.g.,reverttooldnon-source-filterAPIordisplayameaningfulerrormessagetotheuser). 横线处应选()。
A.systems B.programs C.applications D.users正确答案C
