类 IO - io/wait：Ruby 标准库文档

nread → int 点击切换源码

返回无需阻塞即可读取的字节数。如果没有可用信息，则返回零。

您必须 require ‘io/wait’ 才能使用此方法。

static VALUE
io_nread(VALUE io)
{
    rb_io_t *fptr;
    int len;
    ioctl_arg n;

    GetOpenFile(io, fptr);
    rb_io_check_readable(fptr);
    len = rb_io_read_pending(fptr);
    if (len > 0) return INT2FIX(len);

#ifdef HAVE_RB_IO_DESCRIPTOR
    int fd = rb_io_descriptor(io);
#else
    int fd = fptr->fd;
#endif

    if (!FIONREAD_POSSIBLE_P(fd)) return INT2FIX(0);
    if (ioctl(fd, FIONREAD, &n)) return INT2FIX(0);
    if (n > 0) return ioctl_arg2num(n);
    return INT2FIX(0);
}

ready? → 真值或假值点击切换源码

如果无需阻塞即可获取输入，则返回真值；否则返回假值。

您必须 require ‘io/wait’ 才能使用此方法。

static VALUE
io_ready_p(VALUE io)
{
    rb_io_t *fptr;
#ifndef HAVE_RB_IO_WAIT
    struct timeval tv = {0, 0};
#endif

    GetOpenFile(io, fptr);
    rb_io_check_readable(fptr);
    if (rb_io_read_pending(fptr)) return Qtrue;

#ifndef HAVE_RB_IO_WAIT
    return wait_for_single_fd(fptr, RB_WAITFD_IN, &tv) ? Qtrue : Qfalse;
#else
    return io_wait_event(io, RUBY_IO_READABLE, RB_INT2NUM(0), 1);
#endif
}

wait(events, timeout) → 事件掩码，false 或 nil 点击切换源码

wait(timeout = nil, mode = :read) → self，true 或 false

等待直到 IO 准备好指定的事件，并返回准备就绪的事件子集；如果超时，则返回假值。

事件可以是 IO::READABLE、IO::WRITABLE 或 IO::PRIORITY 的位掩码。

当缓冲数据可用时，立即返回真值。

可选参数 mode 是 :read、:write 或 :read_write 之一。

您必须 require ‘io/wait’ 才能使用此方法。

static VALUE
io_wait(int argc, VALUE *argv, VALUE io)
{
#ifndef HAVE_RB_IO_WAIT
    rb_io_t *fptr;
    struct timeval timerec;
    struct timeval *tv = NULL;
    int event = 0;
    int i;

    GetOpenFile(io, fptr);
    for (i = 0; i < argc; ++i) {
        if (SYMBOL_P(argv[i])) {
            event |= wait_mode_sym(argv[i]);
        }
        else {
            *(tv = &timerec) = rb_time_interval(argv[i]);
        }
    }
    /* rb_time_interval() and might_mode() might convert the argument */
    rb_io_check_closed(fptr);
    if (!event) event = RB_WAITFD_IN;
    if ((event & RB_WAITFD_IN) && rb_io_read_pending(fptr))
        return Qtrue;
    if (wait_for_single_fd(fptr, event, tv))
        return io;
    return Qnil;
#else
    VALUE timeout = Qundef;
    rb_io_event_t events = 0;
    int i, return_io = 0;

    /* The documented signature for this method is actually incorrect.
     * A single timeout is allowed in any position, and multiple symbols can be given.
     * Whether this is intentional or not, I don't know, and as such I consider this to
     * be a legacy/slow path. */
    if (argc != 2 || (RB_SYMBOL_P(argv[0]) || RB_SYMBOL_P(argv[1]))) {
        /* We'd prefer to return the actual mask, but this form would return the io itself: */
        return_io = 1;

        /* Slow/messy path: */
        for (i = 0; i < argc; i += 1) {
            if (RB_SYMBOL_P(argv[i])) {
                events |= wait_mode_sym(argv[i]);
            }
            else if (timeout == Qundef) {
                rb_time_interval(timeout = argv[i]);
            }
            else {
                rb_raise(rb_eArgError, "timeout given more than once");
            }
        }

        if (timeout == Qundef) timeout = Qnil;

        if (events == 0) {
            events = RUBY_IO_READABLE;
        }
    }
    else /* argc == 2 and neither are symbols */ {
        /* This is the fast path: */
        events = io_event_from_value(argv[0]);
        timeout = argv[1];
    }

    if (events & RUBY_IO_READABLE) {
        rb_io_t *fptr = NULL;
        RB_IO_POINTER(io, fptr);

        if (rb_io_read_pending(fptr)) {
            /* This was the original behaviour: */
            if (return_io) return Qtrue;
            /* New behaviour always returns an event mask: */
            else return RB_INT2NUM(RUBY_IO_READABLE);
        }
    }

    return io_wait_event(io, events, timeout, return_io);
#endif
}

wait_priority → 真值或假值点击切换源码

wait_priority(timeout) → 真值或假值

等待直到 IO 具有优先级，并返回真值；如果超时，则返回假值。优先级数据使用 Socket::MSG_OOB 标志发送和接收，通常仅限于流。

您必须 require ‘io/wait’ 才能使用此方法。

static VALUE
io_wait_priority(int argc, VALUE *argv, VALUE io)
{
    rb_io_t *fptr = NULL;

    RB_IO_POINTER(io, fptr);
    rb_io_check_readable(fptr);

    if (rb_io_read_pending(fptr)) return Qtrue;

    rb_check_arity(argc, 0, 1);
    VALUE timeout = argc == 1 ? argv[0] : Qnil;

    return io_wait_event(io, RUBY_IO_PRIORITY, timeout, 1);
}

wait_readable → 真值或假值点击切换源码

wait_readable(timeout) → 真值或假值

等待直到 IO 可读，并返回真值；如果超时，则返回假值。当缓冲数据可用时，立即返回真值。

您必须 require ‘io/wait’ 才能使用此方法。

static VALUE
io_wait_readable(int argc, VALUE *argv, VALUE io)
{
    rb_io_t *fptr;
#ifndef HAVE_RB_IO_WAIT
    struct timeval timerec;
    struct timeval *tv;
#endif

    GetOpenFile(io, fptr);
    rb_io_check_readable(fptr);

#ifndef HAVE_RB_IO_WAIT
    tv = get_timeout(argc, argv, &timerec);
#endif
    if (rb_io_read_pending(fptr)) return Qtrue;

#ifndef HAVE_RB_IO_WAIT
    if (wait_for_single_fd(fptr, RB_WAITFD_IN, tv)) {
        return io;
    }
    return Qnil;
#else
    rb_check_arity(argc, 0, 1);
    VALUE timeout = (argc == 1 ? argv[0] : Qnil);

    return io_wait_event(io, RUBY_IO_READABLE, timeout, 1);
#endif
}

wait_writable → 真值或假值点击切换源码

wait_writable(timeout) → 真值或假值

等待直到 IO 可写，并返回真值；如果超时，则返回假值。

您必须 require ‘io/wait’ 才能使用此方法。

static VALUE
io_wait_writable(int argc, VALUE *argv, VALUE io)
{
    rb_io_t *fptr;
#ifndef HAVE_RB_IO_WAIT
    struct timeval timerec;
    struct timeval *tv;
#endif

    GetOpenFile(io, fptr);
    rb_io_check_writable(fptr);

#ifndef HAVE_RB_IO_WAIT
    tv = get_timeout(argc, argv, &timerec);
    if (wait_for_single_fd(fptr, RB_WAITFD_OUT, tv)) {
        return io;
    }
    return Qnil;
#else
    rb_check_arity(argc, 0, 1);
    VALUE timeout = (argc == 1 ? argv[0] : Qnil);

    return io_wait_event(io, RUBY_IO_WRITABLE, timeout, 1);
#endif
}