fopencookie
extern FILE *fopencookie(void *cookie, const char *mode, cookie_io_functions_t io_funcs);
return fopencookie(cookie, *mode == 'w' ? "w" : "r", cio);
versioned_symbol (libc, _IO_fopencookie, fopencookie, GLIBC_2_2);
compat_symbol (libc, _IO_old_fopencookie, fopencookie, GLIBC_2_0);
extern FILE *fopencookie (void *__restrict __magic_cookie,