Microsoft C/C++ provides the option to precompile header files. Precompilation, especially when used in conjunction with the fast compile (/f) option, can dramatically reduce compile time for header files that are frequently compiled without modification. This process saves the state of a compilation (including CodeView information) at a point after header files have been processed. In later compilations, the compiler simply restores the saved compilation state from a precompiled header (.PCH) file, rather than recompiling the unchanged header files.