Force inclusion

Force inclusion of a file instructs the compiler to prepend the compilation unit with the contents of a given file. It is basically saying that an #include "foo.h" should be added at the top of the source file. This can be advantageous if you want to include some code in all the compiled source files without modifying them individually.

Let's see an example:

// foo.h
#define FOO_CONSTANT 123

// main.cpp
#include "foo.h"

int main() {
	return FOO_CONSTANT;
}

The above doesn't use force inclusion, and compiles fine as is. However, if we modify main.cpp by removing the inclusion:

// foo.h
#define FOO_CONSTANT 123

// main.cpp
int main() {
	return FOO_CONSTANT;
}

And use the ForceInclude parameter to add the foo.h to the compilation unit:

saker.msvc.ccompile({
	Files: *.cpp,
	ForceInclude: foo.h,
})

Then the code will compile just as fine. See the /FI compiler option for more information.

(Note that you can specify multiple files to be force included, they will be added in the order they are specified for the parameter.)

Note that if you use force inclusion with precompiled headers, then the force included files will be part of the precompiled header, and are included before the precompiled header contents.