在同一套接字上并行调用 send/recv 是否有效? [英] Are parallel calls to send/recv on the same socket valid?
问题描述
- 我们可以在同一个套接字上从一个线程调用 send 并从另一个线程调用 recv 吗?
- 我们可以从同一个套接字上的不同线程并行调用多个发送吗?
我知道好的设计应该避免这种情况，但我不清楚这些系统 API 的行为方式.我也找不到同样好的文档.
I know that a good design should avoid this, but I am not clear how these system APIs will behave. I am unable to find a good documentation also for the same.
任何有关方向的指示都会有所帮助.
Any pointers in the direction will be helpful.
推荐答案
POSIX 将 send/recv 定义为原子操作，所以假设你在谈论 POSIX send/recv 那么是的，你可以从多个线程和事物同时调用它们会工作.
POSIX defines send/recv as atomic operations, so assuming you're talking about POSIX send/recv then yes, you can call them simultaneously from multiple threads and things will work.
这并不一定意味着它们会并行执行——在多次发送的情况下，第二个可能会阻塞，直到第一个完成.您可能不会注意到这么多，因为一旦将数据放入套接字缓冲区，发送就完成了.
This doesn't necessarily mean that they'll be executed in parallel -- in the case of multiple sends, the second will likely block until the first completes. You probably won't notice this much, as a send completes once its put its data into the socket buffer.
如果您使用 SOCK_STREAM 套接字，那么尝试并行处理的可能性较小，因为 send/recv 可能仅发送或接收消息的一部分，这意味着事情可能会分裂.
If you're using SOCK_STREAM sockets, trying to do things a parallel is less likely to be useful as send/recv might send or receive only part of a message, which means things could get split up.
在 SOCK_STREAM 套接字上阻塞发送/接收只会阻塞直到它们发送或接收至少 1 个字节，因此阻塞和非阻塞之间的区别没有用.
Blocking send/recv on SOCK_STREAM sockets only block until they send or recv at least 1 byte, so the difference between blocking and non-blocking is not useful.
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