Method: IO#nread

Defined in:
wait/wait.c

#nread ⇒ Integer

Returns number of bytes that can be read without blocking. Returns zero if no information available.



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# File 'wait/wait.c', line 51

static VALUE
io_nread(VALUE io)
{
    rb_io_t *fptr = NULL;
    ioctl_arg n;

    GetOpenFile(io, fptr);
    rb_io_check_readable(fptr);
    int len = rb_io_read_pending(fptr);
    if (len > 0) return INT2FIX(len);
    if (!FIONREAD_POSSIBLE_P(fptr->fd)) return INT2FIX(0);
    if (ioctl(fptr->fd, FIONREAD, &n)) return INT2FIX(0);
    if (n > 0) return ioctl_arg2num(n);
    return INT2FIX(0);
}