windows.h is a source code header file that Microsoft provides for the development of programs that access the Windows API (WinAPI) via C language syntax. It declares the WinAPI functions, associated data types and common macros. Access to WinAPI can enabled for a C or C++ program by including it into a source file: #include <windows.h> Also, the executable must be linked to each static library that either contains the function code or more commonly defines runtime, dynamic linking to a system dynamic link library (DLL). Generally, for functions in a DLL named like Abc.dll, the program must be linked to a library named like Abc.lib. For MinGW, the library name is like libAbc.dll.a.

Included header files

Including windows.h results in including various other header files that are included directly or indirectly by windows.h. Many of these header files cannot be included on their own due dependencies between the various header files. Notable included header files:

Standard C

Basic

Extra

OLE and COM

Macros

Several macros affect the definitions made by windows.h and the files it includes.