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"),a("a",{attrs:{href:"https://beej.us/guide/bgnet/output/html/singlepage/bgnet.html",target:"_blank",rel:"noopener noreferrer"}},[t._v("Beej's Guide to Network Programming"),a("OutboundLink")],1),t._v(' and give it a quick read, which explains most of this stuff a bit more verbosely. We\'ll be creating a simple TCP server here which will say "Hello World" to all incoming connections and then close them. Another thing to note is, the server will be communicating to clients iteratively, which means one client at a time. Make sure to check out relevant man pages as they might contain valuable information about each function call and socket structures.')]),t._v(" "),a("p",[t._v("We'll run the server with a port, so we'll take an argument for port number as well. Let's get started with code -")]),t._v(" "),a("div",{staticClass:"language-cpp extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cpp"}},[a("code",[a("span",{pre:!0,attrs:{class:"token macro property"}},[a("span",{pre:!0,attrs:{class:"token directive-hash"}},[t._v("#")]),a("span",{pre:!0,attrs:{class:"token directive keyword"}},[t._v("include")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v("<cstring>")]),t._v("    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// sizeof()")])]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token macro property"}},[a("span",{pre:!0,attrs:{class:"token directive-hash"}},[t._v("#")]),a("span",{pre:!0,attrs:{class:"token directive keyword"}},[t._v("include")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v("<iostream>")])]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token macro property"}},[a("span",{pre:!0,attrs:{class:"token directive-hash"}},[t._v("#")]),a("span",{pre:!0,attrs:{class:"token directive 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"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("auto")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("&")]),t._v("portNum "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" argv"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("const")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("unsigned")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("int")]),t._v(" backLog "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("8")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("  "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// number of connections allowed on the incoming queue")]),t._v("\n\n\n    addrinfo hints"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("*")]),t._v("res"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("*")]),t._v("p"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// we need 2 pointers, res to hold and p to iterate over")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("memset")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("&")]),t._v("hints"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("sizeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("hints"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// for more explanation, man socket")]),t._v("\n    hints"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("ai_family   "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" AF_UNSPEC"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// don't specify which IP version to use yet")]),t._v("\n    hints"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("ai_socktype "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" SOCK_STREAM"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("  "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// SOCK_STREAM refers to TCP, SOCK_DGRAM will be?")]),t._v("\n    hints"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("ai_flags    "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" AI_PASSIVE"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// man getaddrinfo")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("int")]),t._v(" gAddRes "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("getaddrinfo")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token 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std"),a("span",{pre:!0,attrs:{class:"token double-colon punctuation"}},[t._v("::")]),t._v("cout "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Detecting addresses"')]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" std"),a("span",{pre:!0,attrs:{class:"token double-colon punctuation"}},[t._v("::")]),t._v("endl"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("unsigned")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("int")]),t._v(" numOfAddr "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("char")]),t._v(" ipStr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),t._v("INET6_ADDRSTRLEN"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// ipv6 length makes sure both ipv4/6 addresses can be stored in this variable")]),t._v("\n\n\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Now since getaddrinfo() has given us a list of addresses")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// we're going to iterate over them and ask user to choose one")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// address for program to bind to")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("for")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("p "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" res"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" p "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("!=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token constant"}},[t._v("NULL")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" p "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" p"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("->")]),t._v("ai_next"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("void")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("*")]),t._v("addr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        std"),a("span",{pre:!0,attrs:{class:"token double-colon punctuation"}},[t._v("::")]),t._v("string ipVer"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n        "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// if address is ipv4 address")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("p"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("->")]),t._v("ai_family "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("==")]),t._v(" AF_INET"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n            ipVer             "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"IPv4"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            sockaddr_in "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("*")]),t._v("ipv4 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token generic-function"}},[a("span",{pre:!0,attrs:{class:"token function"}},[t._v("reinterpret_cast")]),a("span",{pre:!0,attrs:{class:"token generic class-name"}},[a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<")]),t._v("sockaddr_in "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("*")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v(">")])])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("p"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("->")]),t._v("ai_addr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            addr              "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("&")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("ipv4"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("->")]),t._v("sin_addr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("++")]),t._v("numOfAddr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n        "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// if address is ipv6 address")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("else")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n            ipVer              "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"IPv6"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            sockaddr_in6 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("*")]),t._v("ipv6 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token generic-function"}},[a("span",{pre:!0,attrs:{class:"token function"}},[t._v("reinterpret_cast")]),a("span",{pre:!0,attrs:{class:"token generic class-name"}},[a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<")]),t._v("sockaddr_in6 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("*")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v(">")])])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("p"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("->")]),t._v("ai_addr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            addr               "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("&")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("ipv6"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("->")]),t._v("sin6_addr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("++")]),t._v("numOfAddr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n        "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// convert IPv4 and IPv6 addresses from binary to text form")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("inet_ntop")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("p"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("->")]),t._v("ai_family"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" addr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" ipStr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("sizeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("ipStr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        std"),a("span",{pre:!0,attrs:{class:"token double-colon punctuation"}},[t._v("::")]),t._v("cout "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"("')]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" numOfAddr "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('") "')]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" ipVer "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('" : "')]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" ipStr\n                  "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" std"),a("span",{pre:!0,attrs:{class:"token double-colon punctuation"}},[t._v("::")]),t._v("endl"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// if no addresses found :(")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("!")]),t._v("numOfAddr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n        std"),a("span",{pre:!0,attrs:{class:"token double-colon punctuation"}},[t._v("::")]),t._v("cerr "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Found no host address to use\\n"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("return")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("-")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("3")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// ask user to choose an address")]),t._v("\n    std"),a("span",{pre:!0,attrs:{class:"token double-colon punctuation"}},[t._v("::")]),t._v("cout "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Enter the number of host address to bind with: "')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("unsigned")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("int")]),t._v(" choice "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("bool")]),t._v(" madeChoice     "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token boolean"}},[t._v("false")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("do")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n        std"),a("span",{pre:!0,attrs:{class:"token double-colon punctuation"}},[t._v("::")]),t._v("cin "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v(">>")]),t._v(" choice"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("choice "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v(">")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("numOfAddr "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("||")]),t._v(" choice "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n            madeChoice "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token boolean"}},[t._v("false")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            std"),a("span",{pre:!0,attrs:{class:"token double-colon punctuation"}},[t._v("::")]),t._v("cout "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Wrong choice, try again!"')]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" std"),a("span",{pre:!0,attrs:{class:"token double-colon punctuation"}},[t._v("::")]),t._v("endl"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("else")]),t._v("\n            madeChoice "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token boolean"}},[t._v("true")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("while")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("!")]),t._v("madeChoice"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n\n\n    p "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" res"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// let's create a new socket, socketFD is returned as descriptor")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// man socket for more information")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// these calls usually return -1 as result of some error")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("int")]),t._v(" sockFD "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("socket")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("p"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("->")]),t._v("ai_family"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" p"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("->")]),t._v("ai_socktype"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" p"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("->")]),t._v("ai_protocol"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("sockFD "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("==")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("-")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n        std"),a("span",{pre:!0,attrs:{class:"token double-colon punctuation"}},[t._v("::")]),t._v("cerr "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Error while creating socket\\n"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("freeaddrinfo")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("res"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("return")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("-")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("4")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Let's bind address to our socket we've just created")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("int")]),t._v(" bindR "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("bind")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("sockFD"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" p"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("->")]),t._v("ai_addr"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" p"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("->")]),t._v("ai_addrlen"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("bindR "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("==")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("-")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n        std"),a("span",{pre:!0,attrs:{class:"token double-colon punctuation"}},[t._v("::")]),t._v("cerr "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Error while binding socket\\n"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        \n        "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// if some error occurs, make sure to close socket and free resources")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("close")]),a("span",{pre:!0,attrs:{class:"token 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