recv函数的第四个参数是什么意思

一个线程收，一个线程发数据。

下面是第四个参数的原文解释：

The flags parameter can be used to influence the behavior of the function invocation beyond the options specified for the associated socket. The semantics of this function are determined by the socket options and the flags parameter. The latter is constructed by using the bitwise OR operator with any of the following values.

Value Meaning

MSG_PEEK

Peeks at the incoming data. The data is copied into the buffer but is not removed from the input queue. The function subsequently returns the amount of data that can be read in a single call to the recv (or recvfrom) function, which may not be the same as the total amount of data queued on the socket. The amount of data that can actually be read in a single call to the recv (or recvfrom) function is limited to the data size written in the send or sendto function call.

MSG_OOB

Processes OOB data. (See DECnet Out-of-band data for a discussion of this topic.)

MSND解释，我不太会翻译，凑合看吧。可能需要编码研究一下