rt_sys.h defines the type
The value of
FILEHANDLE is returned by
_sys_open() and identifies
an open file on the host system.
Target-dependent I/O functions use semihosting. If any function is redefined, all stream-support functions must be redefined.
are redefined, both normal character I/O and wide character I/O
works. That is, you are not required to do anything extra with these
functions for wide character I/O to work.