You may get compilation errors for afxsock.h

Source: Microsoft Support

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Compile/ Build VC++ projects that use afxsock.h header file and have defined _WIN32_WINNT less than 0x0501.

Build fails with the following errors :



Error 1 error C2065: 'IPPROTO_IPV6' : undeclared identifier c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\atlsocket.inl 130
Error 2 error C2065: 'SOCKADDR_STORAGE' : undeclared identifier c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 381
Error 3 error C2146: syntax error : missing ';' before identifier 'sockAddr' c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 381
Error 4 error C2065: 'sockAddr' : undeclared identifier c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 381
Error 5 error C2070: ''unknown-type'': illegal sizeof operand c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 382
Error 6 error C2070: ''unknown-type'': illegal sizeof operand c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 384
Error 7 error C2227: left of '->sin_port' must point to class/struct/union/generic type c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 394
Error 8 error C2146: syntax error : missing ';' before identifier 'sockAddr' c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 402
Error 9 error C2070: ''unknown-type'': illegal sizeof operand c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 403
Error 10 error C2070: ''unknown-type'': illegal sizeof operand c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 405
Error 11 error C2227: left of '->sin_port' must point to class/struct/union/generic type c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 415
Error 12 error C2146: syntax error : missing ';' before identifier 'sockAddr' c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 423
Error 13 error C2070: ''unknown-type'': illegal sizeof operand c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 424
Error 14 error C2070: ''unknown-type'': illegal sizeof operand c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 426
Error 15 error C2227: left of '->sin_port' must point to class/struct/union/generic type c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 436
Error 16 error C2146: syntax error : missing ';' before identifier 'sockAddrSelf' c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 450
Error 17 error C2065: 'sockAddrSelf' : undeclared identifier c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 450
Error 18 error C2070: ''unknown-type'': illegal sizeof operand c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 451
Error 19 error C2070: ''unknown-type'': illegal sizeof operand c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 453
Error 20 error C2228: left of '.ss_family' must have class/struct/union c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\afxsock.h 470

Project has defined _WIN32_WINNT macro value less than minimum recommended for the Operating System, and Windows XP SP2 is minimum required for these structures.

For example, if you set _WIN32_WINNT to 0x0500 or less, you will get the listed errors.

Change the preprocessor definition to a version higher or equal to the minimum recommended.
See Using the Windows Headers (http://msdn2.microsoft.com/en-us/library/aa383745.aspx)  for values to use.

If it is inherited from project defaults or parent project uncheck the following settings :
Project->Properties-> Configuration Properties->C/C++->Preprocessor->Preprocessor Definitions->inherit from parent or project defaults.

See also
SOCKADDR_STORAGE Structure (http://msdn2.microsoft.com/en-us/library/ms740504.aspx)

Note :
The WINVER and _WIN32_WINNT macros are legacy macros. You can also use the new macros starting with NTDDI_* ( for example NTDDI_VISTASP1 for Windows Vista SP1 ) (http://msdn2.microsoft.com/en-us/library/ms740504.aspx)

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