3.27 Obsolete Precompiled Header (PCH) files
In automatic PCH processing mode the compiler identifies and deletes obsolete PCH files.
The compiler indicates that a PCH file is obsolete, and
deletes it, under the following circumstances:
If the PCH file is based on at least one out-of-date header file but is otherwise
applicable for the current compilation.
If the PCH file has the same base name as the source file being compiled, for
example, xxx.pch and xxx.c, but is not
applicable for the current compilation, for example, because you have used different
These describe some common cases. You must delete other PCH files as required.