title: Can't include Winsock2.h in MSVC 2010
body: <p>I cannot include WinSock2.h in a msvc++2010 project. At first I though it was something I was doing wrong, so I created an empty project to test my sanity. The empty project is as follows</p>
  
  <pre><code>#include &lt;Windows.h&gt;
  #include &lt;WinSock2.h&gt;
  
  
  int main(void){
  
      system("echo Hello World");
      system("pause");
      return 0;
  
  };
  </code></pre>
  
  <p>It compiles and works fine without the line <code>#include &lt;WinSock2.h&gt;</code> but it fails with a long list of errors when I do try and include WinSock2.h. </p>
  
  <p>Errors:</p>
  
  <pre><code>1&gt;  Main.cpp
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\ws2def.h(91): warning C4005: 'AF_IPX' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(460) : see previous definition of 'AF_IPX'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\ws2def.h(131): warning C4005: 'AF_MAX' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(479) : see previous definition of 'AF_MAX'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\ws2def.h(168): warning C4005: 'SO_DONTLINGER' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(402) : see previous definition of 'SO_DONTLINGER'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\ws2def.h(212): error C2011: 'sockaddr' : 'struct' type redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(485) : see declaration of 'sockaddr'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\ws2def.h(390): error C2059: syntax error : 'constant'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\ws2def.h(390): error C3805: 'constant': unexpected token, expected either '}' or a ','
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\ws2def.h(524): warning C4005: 'IN_CLASSA' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(287) : see previous definition of 'IN_CLASSA'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\ws2def.h(530): warning C4005: 'IN_CLASSB' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(293) : see previous definition of 'IN_CLASSB'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\ws2def.h(536): warning C4005: 'IN_CLASSC' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(299) : see previous definition of 'IN_CLASSC'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\ws2def.h(547): warning C4005: 'INADDR_ANY' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(304) : see previous definition of 'INADDR_ANY'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\ws2def.h(549): warning C4005: 'INADDR_BROADCAST' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(306) : see previous definition of 'INADDR_BROADCAST'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\ws2def.h(583): error C2011: 'sockaddr_in' : 'struct' type redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(312) : see declaration of 'sockaddr_in'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(132): error C2011: 'fd_set' : 'struct' type redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(68) : see declaration of 'fd_set'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(167): warning C4005: 'FD_SET' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(102) : see previous definition of 'FD_SET'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(176): error C2011: 'timeval' : 'struct' type redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(111) : see declaration of 'timeval'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(232): error C2011: 'hostent' : 'struct' type redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(167) : see declaration of 'hostent'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(245): error C2011: 'netent' : 'struct' type redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(180) : see declaration of 'netent'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(252): error C2011: 'servent' : 'struct' type redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(187) : see declaration of 'servent'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(264): error C2011: 'protoent' : 'struct' type redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(199) : see declaration of 'protoent'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(360): error C2011: 'WSAData' : 'struct' type redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(322) : see declaration of 'WSAData'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(458): error C2011: 'sockproto' : 'struct' type redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(494) : see declaration of 'sockproto'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(500): error C2011: 'linger' : 'struct' type redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(531) : see declaration of 'linger'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(513): warning C4005: 'SOMAXCONN' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(544) : see previous definition of 'SOMAXCONN'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(542): warning C4005: 'FD_READ' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(562) : see previous definition of 'FD_READ'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(545): warning C4005: 'FD_WRITE' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(563) : see previous definition of 'FD_WRITE'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(548): warning C4005: 'FD_OOB' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(564) : see previous definition of 'FD_OOB'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(551): warning C4005: 'FD_ACCEPT' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(565) : see previous definition of 'FD_ACCEPT'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(554): warning C4005: 'FD_CONNECT' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(566) : see previous definition of 'FD_CONNECT'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(557): warning C4005: 'FD_CLOSE' : macro redefinition
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(567) : see previous definition of 'FD_CLOSE'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1578): error C2375: 'accept' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(742) : see declaration of 'accept'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1600): error C2375: 'bind' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(747) : see declaration of 'bind'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1619): error C2375: 'closesocket' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(752) : see declaration of 'closesocket'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1638): error C2375: 'connect' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(754) : see declaration of 'connect'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1659): error C2375: 'ioctlsocket' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(759) : see declaration of 'ioctlsocket'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1680): error C2375: 'getpeername' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(764) : see declaration of 'getpeername'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1701): error C2375: 'getsockname' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(769) : see declaration of 'getsockname'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1724): error C2375: 'getsockopt' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(774) : see declaration of 'getsockopt'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1745): error C2375: 'htonl' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(781) : see declaration of 'htonl'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1762): error C2375: 'htons' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(783) : see declaration of 'htons'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1780): error C2375: 'inet_addr' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(785) : see declaration of 'inet_addr'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1797): error C2375: 'inet_ntoa' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(787) : see declaration of 'inet_ntoa'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1815): error C2375: 'listen' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(789) : see declaration of 'listen'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1833): error C2375: 'ntohl' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(793) : see declaration of 'ntohl'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1850): error C2375: 'ntohs' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(795) : see declaration of 'ntohs'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1870): error C2375: 'recv' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(797) : see declaration of 'recv'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1895): error C2375: 'recvfrom' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(803) : see declaration of 'recvfrom'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1921): error C2375: 'select' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(811) : see declaration of 'select'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1945): error C2375: 'send' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(818) : see declaration of 'send'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1970): error C2375: 'sendto' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(824) : see declaration of 'sendto'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(1996): error C2375: 'setsockopt' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(832) : see declaration of 'setsockopt'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2018): error C2375: 'shutdown' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(839) : see declaration of 'shutdown'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2039): error C2375: 'socket' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(843) : see declaration of 'socket'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2063): error C2375: 'gethostbyaddr' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(850) : see declaration of 'gethostbyaddr'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2083): error C2375: 'gethostbyname' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(855) : see declaration of 'gethostbyname'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2101): error C2375: 'gethostname' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(857) : see declaration of 'gethostname'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2121): error C2375: 'getservbyport' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(861) : see declaration of 'getservbyport'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2141): error C2375: 'getservbyname' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(865) : see declaration of 'getservbyname'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2160): error C2375: 'getprotobynumber' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(869) : see declaration of 'getprotobynumber'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2178): error C2375: 'getprotobyname' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(871) : see declaration of 'getprotobyname'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2200): error C2375: 'WSAStartup' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(875) : see declaration of 'WSAStartup'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2219): error C2375: 'WSACleanup' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(879) : see declaration of 'WSACleanup'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2236): error C2375: 'WSASetLastError' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(881) : see declaration of 'WSASetLastError'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2253): error C2375: 'WSAGetLastError' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(883) : see declaration of 'WSAGetLastError'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2270): error C2375: 'WSAIsBlocking' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(885) : see declaration of 'WSAIsBlocking'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2287): error C2375: 'WSAUnhookBlockingHook' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(887) : see declaration of 'WSAUnhookBlockingHook'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2304): error C2375: 'WSASetBlockingHook' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(889) : see declaration of 'WSASetBlockingHook'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2321): error C2375: 'WSACancelBlockingCall' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(891) : see declaration of 'WSACancelBlockingCall'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2343): error C2375: 'WSAAsyncGetServByName' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(893) : see declaration of 'WSAAsyncGetServByName'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2370): error C2375: 'WSAAsyncGetServByPort' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(901) : see declaration of 'WSAAsyncGetServByPort'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2396): error C2375: 'WSAAsyncGetProtoByName' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(909) : see declaration of 'WSAAsyncGetProtoByName'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2421): error C2375: 'WSAAsyncGetProtoByNumber' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(916) : see declaration of 'WSAAsyncGetProtoByNumber'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2446): error C2375: 'WSAAsyncGetHostByName' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(923) : see declaration of 'WSAAsyncGetHostByName'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2473): error C2375: 'WSAAsyncGetHostByAddr' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(930) : see declaration of 'WSAAsyncGetHostByAddr'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2496): error C2375: 'WSACancelAsyncRequest' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(939) : see declaration of 'WSACancelAsyncRequest'
  1&gt;c:\program files\microsoft sdks\windows\v7.0a\include\winsock2.h(2517): error C2375: 'WSAAsyncSelect' : redefinition; different linkage
  1&gt;          c:\program files\microsoft sdks\windows\v7.0a\include\winsock.h(941) : see declaration of 'WSAAsyncSelect'
  ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
  </code></pre>
  
  <p>I am assuming that Microsoft would not distribute bad header files in their SDK, what's going on?</p>