What does EAGAIN mean?

Question

在标题中，EAGAIN是什么意思？

Answer 1

EAGAIN is often raised when performing non-blocking I/O . It means "there is no data available right now, try again later" .

It might (or might not ) be the same as EWOULDBLOCK , which means "your thread would have to block in order to do that" .

Answer 2

Using man 2 intro | less -Ip EAGAIN man 2 intro | less -Ip EAGAIN :

     35 EAGAIN Resource temporarily unavailable.  This is a temporary condi-
         tion and later calls to the same routine may complete normally.

Answer 3

What it means is less important. What it implies:

• your system call failed
• nothing happened (system calls are atomic, and this one just did not happen)
• you could try it again (it could fail again , possibly with a different result)
• or you could choose otherwise.

The whole thing about EAGAIN is that your process is not blocked inside the system call; it has the right to choose: either retry or do something useful.

Answer 4

根据这个 ，它的意思是“操作会导致进程暂停。”