"Windows" did this 11 years ago: >FILE Encapsulation: In previous versions, the FILE type was completely defined in <stdio.h>, so it was possible for user code

"Windows" did this 11 years ago: >FILE Encapsulation: In previous versions, the FILE type was completely defined in <stdio.h>, so it was possible for user code to reach into a FILE and muck with its internals. We have refactored the stdio library to improve encapsulation of the library implementation details. As part of this, FILE as defined in <stdio.h> is now an opaque type and its members are inaccessible from outside of the CRT itself. https://devblogs.microsoft.com/cppblog/c-runtime-crt-features-fixes-and-breaking-changes-in-visual-studio-14-ctp1/ https://devblogs.microsoft.com/cppblog/c-runtime-crt-feature...