基于UDP协议的WinSock编程

《基于UDP协议的WinSock编程》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、WinSocket编程（基于UDP）对于在一个无连接套接字上接收数据的进程来说，步骤并不复杂。先用WSAStartup来加载WinscockDLL相应版本，然后用socket或WSASocket建立套接字。再把这个套接字和准备接收数据的接口绑定在一起。这是通过bind函数来完成的。和面向连接会话不同的是，我们不必调用listen和accept。1、Winsock的初始化每个Winsock应用都必须加载WinsockDLL的相应版本。如果调用Winsock之前，没有加载Winsock库，这个函数就会返回一个SOCKET_ERROR，错误信息是WSANOTINITIALISED。加载Winsoc

2、k库是通过调用WSAStartup函数实现的。这个函数的定义如下：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.注释：TheWSAStartupfunctionmustbethefirstWindowsSocketsfunctionc

6、alledbyanapplicationorDLL.ItallowsanapplicationorDLLtospecifytheversionofWindowsSocketsrequiredandretrievedetailsofthespecificWindowsSocketsimplementation.TheapplicationorDLLcanonlyissuefurtherWindowsSocketsfunctionsaftersuccessfullycallingWSAStartup.（在使用WindowsSockets之前必须调用WSAStartup加载Winsocket库成功

7、）　　OnceanapplicationorDLLhasmadeasuccessfulWSAStartupcall,itcanproceedtomakeotherWindowsSocketscallsasneeded.WhenithasfinishedusingtheservicesoftheWs2_32.dll,theapplicationorDLLmustcallWSACleanuptoallowtheW