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《基于UDP協(xié)議的WinSock編程》由會員上傳分享，免費在線閱讀，更多相關(guān)內(nèi)容在教育資源-天天文庫。
1、WinSocket編程（基于UDP）對于在一個無連接套接字上接收數(shù)據(jù)的進程來說，步驟并不復雜。先用WSAStartup來加載WinscockDLL相應版本，然后用socket或WSASocket建立套接字。再把這個套接字和準備接收數(shù)據(jù)的接口綁定在一起。這是通過bind函數(shù)來完成的。和面向連接會話不同的是，我們不必調(diào)用listen和accept。1、Winsock的初始化每個Winsock應用都必須加載WinsockDLL的相應版本。如果調(diào)用Winsock之前，沒有加載Winsock庫，這個函數(shù)就會返回一個SOCKET_ERROR，錯誤信息是WSANOTINITIALISED。加載Winsoc
2、k庫是通過調(diào)用WSAStartup函數(shù)實現(xiàn)的。這個函數(shù)的定義如下：intWSAStartup(WORDwVersionRequested,LPWSADATAlpWSAData);wVersionRequested[in]HighestversionofWindowsSocketssupportthatthecallercanuse.Thehigh-orderbytespecifiestheminorversion(revision)number;thelow-orderbytespecifiesthemajorversionnumber.lpWSAData[out]PointertotheW
3、SADATAdatastructurethatistoreceivedetailsoftheWindowsSocketsimplementation.TheWSAStartupfunctionreturnszeroifsuccessful.Otherwise,itreturnsoneoftheerrorcodeslistedinthefollowing.AnapplicationcannotcallWSAGetLastErrortodeterminetheerrorcodeasisnormallydoneinWindowsSocketsifWSAStartupfails.TheWs2_32.
4、dllwillnothavebeenloadedinthecaseofafailuresotheclientdataareawherethelasterrorinformationisstoredcouldnotbeestablished.ErrorcodeMeaningWSASYSNOTREADYIndicatesthattheunderlyingnetworksubsystemisnotreadyfornetworkcommunication.WSAVERNOTSUPPORTEDTheversionofWindowsSocketssupportrequestedisnotprovided
5、bythisparticularWindowsSocketsimplementation.WSAEINPROGRESSAblockingWindowsSockets1.1operationisinprogress.WSAEPROCLIMLimitonthenumberoftaskssupportedbytheWindowsSocketsimplementationhasbeenreached.WSAEFAULTThelpWSADataisnotavalidpointer.注釋：TheWSAStartupfunctionmustbethefirstWindowsSocketsfunctionc
6、alledbyanapplicationorDLL.ItallowsanapplicationorDLLtospecifytheversionofWindowsSocketsrequiredandretrievedetailsofthespecificWindowsSocketsimplementation.TheapplicationorDLLcanonlyissuefurtherWindowsSocketsfunctionsaftersuccessfullycallingWSAStartup.（在使用WindowsSockets之前必須調(diào)用WSAStartup加載Winsocket庫成功
7、） OnceanapplicationorDLLhasmadeasuccessfulWSAStartupcall,itcanproceedtomakeotherWindowsSocketscallsasneeded.WhenithasfinishedusingtheservicesoftheWs2_32.dll,theapplicationorDLLmustcallWSACleanuptoallowtheW
