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fatal error C1189: #error : &nbsp;WINDOWS.H already included. &nbsp;MFC apps must not #include &lt;windows.h&gt;
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fatal error C1189: #error :  WINDOWS.H already included.  MFC apps must not #include <windows.h>

fatal error 1189

Kernel and system programming is the process of creating the software necessary for a computer or device to function and operate other programs. Some operating systems (such as Microsoft Windows) are proprietary, but others, such as the various Linux distributions, are open source.