At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga.
Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus.
Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
Isn't that an allergy medicine?
It's included in every new Visual Studio C++ project
Not the answer you are looking for? Search for more explanations.
Theoretically it should save time since the headers don't have to be re-parsed.
It used to be a header file for "Application Framework Extensions", a set of functionality that was later extended into MFC. MFC was then deprecated and abandoned, but the header file lived on as a precompiled header.
It's commonly used to just include everything your project needs and precompile it, but that's a double edged sword. On one hand, you can group a bunch of includes in a single header file, on the other, that's simply bad practice because it counteracts modularization and can actually significantly increase compile times when you modify header files. Technically you should avoid using the #include directive in header files - because it means every file that includes your header, will also include everything your header includes, and so on.