instance method
IO#eof
() -> bool
eof → true or false
io.c
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VALUE
rb_io_eof(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
if (READ_CHAR_PENDING(fptr)) return Qfalse;
if (READ_DATA_PENDING(fptr)) return Qfalse;
READ_CHECK(fptr);
#if RUBY_CRLF_ENVIRONMENT
if (!NEED_READCONV(fptr) && NEED_NEWLINE_DECORATOR_ON_READ(fptr)) {
return RBOOL(eof(fptr->fd));
}
#endif
return RBOOL(io_fillbuf(fptr) < 0);
}
Returns true if the stream is positioned at its end, false otherwise; see Position:
Example
f = File.open('t.txt') f.eof # => false f.seek(0, :END) # => 0 f.eof # => true f.close
Raises an exception unless the stream is opened for reading; see Mode.
If self is a stream such as pipe or socket, this method blocks until the other end sends some data or closes it:
Example
r, w = IO.pipe Thread.new { sleep 1; w.close } r.eof? # => true # After 1-second wait. r, w = IO.pipe Thread.new { sleep 1; w.puts "a" } r.eof? # => false # After 1-second wait. r, w = IO.pipe r.eof? # blocks forever
Note that this method reads data to the input byte buffer. So IO#sysread may not behave as you intend with IO#eof?, unless you call IO#rewind first (which is not available for some streams).