EEPW论坛

在源码中tcp_write函数的注释：

/**
 * Write data for sending (but does not send it immediately).
 *
 * It waits in the expectation of more data being sent soon (as
 * it can send them more efficiently by combining them together).
 * To prompt the system to send data now, call tcp_output() after
 * calling tcp_write().
 *
 * @param pcb Protocol control block for the TCP connection to enqueue data for.
 * @param arg Pointer to the data to be enqueued for sending.
 * @param len Data length in bytes
 * @param apiflags combination of following flags :
 * - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
 * - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
 * @return ERR_OK if enqueued, another err_t on error
 */
err_t
tcp_write(struct tcp_pcb *pcb, const void *arg, u16_t len, u8_t apiflags)
{
  struct pbuf *concat_p = NULL;
  struct tcp_seg *last_unsent = NULL, *seg = NULL, *prev_seg = NULL, *queue = NULL;
  u16_t pos = 0; /* position in 'arg' data */

在注释中
tcp_write(struct tcp_pcb *pcb, const void *arg, u16_t len, u8_t apiflags)

最后一个参数

 * - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
 * - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,

想请问，当apiflags分别为0x00,0x01,0x02 时有什么不同，分别适用于哪种情况？？？