golang 的 func (c *IPConn) Write(b []byte)

Question

我猜 int 是写入的字节数。我认为函数会阻塞，直到缓冲区完全写入套接字或套接字关闭，所以我认为这个数字没有任何关系（不像在交流套接字中我需要用未写入的字节重试写入）。我想唯一可以返回的错误是在写入失败的情况下，因为套接字已关闭？这些似乎都没有出现在https://golang.org/pkg/net/#IPConn.Write的文档中，还是我找错了地方？

Answer 1

包io

import "io" 

类型作家

type Writer interface {

        Write(p []byte) (n int, err error)

}

Writer 是封装了基本 Write 方法的接口。

Write 将 len(p) 个字节从 p 写入底层数据流。它返回从 p (0 <= n <= len(p)) 写入的字节数以及导致写入提前停止的任何错误。如果 Write 返回 n < len(p)，则它必须返回一个非 nil 错误。写入不得修改切片数据，即使是临时修改。

实现不能保留 p。

包网

导入“网”

类型连接

type Conn interface {

        // Read reads data from the connection.

        // Read can be made to time out and return a Error with Timeout() == true

        // after a fixed time limit; see SetDeadline and SetReadDeadline.

        Read(b []byte) (n int, err error)

        // Write writes data to the connection.

        // Write can be made to time out and return a Error with Timeout() == true

        // after a fixed time limit; see SetDeadline and SetWriteDeadline.

        Write(b []byte) (n int, err error)

        // Close closes the connection.

        // Any blocked Read or Write operations will be unblocked and return errors.

        Close() error

        // LocalAddr returns the local network address.

        LocalAddr() Addr

        // RemoteAddr returns the remote network address.

        RemoteAddr() Addr

        // SetDeadline sets the read and write deadlines associated

        // with the connection. It is equivalent to calling both

        // SetReadDeadline and SetWriteDeadline.

        //

        // A deadline is an absolute time after which I/O operations

        // fail with a timeout (see type Error) instead of

        // blocking. The deadline applies to all future I/O, not just

        // the immediately following call to Read or Write.

        //

        // An idle timeout can be implemented by repeatedly extending

        // the deadline after successful Read or Write calls.

        //

        // A zero value for t means I/O operations will not time out.

        SetDeadline(t time.Time) error

        // SetReadDeadline sets the deadline for future Read calls.

        // A zero value for t means Read will not time out.

        SetReadDeadline(t time.Time) error

        // SetWriteDeadline sets the deadline for future Write calls.

        // Even if write times out, it may return n > 0, indicating that

        // some of the data was successfully written.

        // A zero value for t means Write will not time out.

        SetWriteDeadline(t time.Time) error

}

Conn 是一个通用的面向流的网络连接。

多个 goroutine 可以同时调用 Conn 上的方法。

func (*IPConn) 写

func (c *IPConn) Write(b []byte) (int, error)

Write 实现了 Conn Write 方法。

它是 io.Writer 接口的实现。Write 将 len(p) 个字节从 p 写入底层数据流。它返回从 p (0 <= n <= len(p)) 写入的字节数 (n) 以及遇到导致写入提前停止的任何 > 错误 (err)。

特别是，对于 net.Conn 接口， func (*IPConn) Write 将数据写入连接。可以使写入超时并在固定时间限制后使用 Timeout() == true 返回错误；请参阅 SetDeadline 和 SetWriteDeadline。

Answer 2

它用于基于 SetWriteDeadline 的超时。如果超时并写入了一些字节，您就会知道写入了多少字节。