FMODE_PREP       3036 io.c           #define IS_PREP_STDIO(f) ((f)->mode & FMODE_PREP)
FMODE_PREP       5231 io.c               fptr->mode = orig->mode | (fptr->mode & FMODE_PREP);
FMODE_PREP       5386 io.c               fptr->mode = orig->mode & ~FMODE_PREP;
FMODE_PREP       5826 io.c               VALUE io = prep_io(fileno(f), fmode|FMODE_PREP, klass, path);