-/* Read a character with user-specified timeout. TIMEOUT is number of seconds
- to wait, or -1 to wait forever. Use timeout of 0 to effect a poll. Returns
- char if successful. Returns -2 if timeout expired, EOF if line dropped
- dead, or -3 for any other error (see errno in that case). */
+/* Read a character with user-specified timeout. TIMEOUT is number of
+ seconds to wait, or -1 to wait forever. Use timeout of 0 to effect
+ a poll. Returns char if successful. Returns SERIAL_TIMEOUT if
+ timeout expired, SERIAL_EOF if line dropped dead, or SERIAL_ERROR
+ for any other error (see errno in that case). */