phil you need to switch to include/c/bits from include/c_std/bits for headers like this. That's why that directory was created. It should work. > #include <iso/stdio_iso.h> > > #if __cplusplus >= 199711L > using std::FILE; > using std::size_t; > using std::fpos_t; > using std::remove; > using std::rename; > ... > #endif