套接字accept()是否返回描述符阻塞或非阻塞？

Question

套接字描述符是由accept()函数在阻塞或非阻塞模式下返回的吗？

Answer 1

不，套接字不会从侦听套接字继承非阻塞状态。你必须自己让它不阻塞。

Answer 2

来自man 2 accept:

   int accept4(int sockfd, struct sockaddr *addr,
               socklen_t *addrlen, int flags);

进一步向下:

   If flags is 0, then accept4() is the same as accept().   The  following
   values can be bitwise ORed in flags to obtain different behavior:

   SOCK_NONBLOCK   Set  the  O_NONBLOCK  file  status flag on the new open
                   file description.  Using this flag saves extra calls to
                   fcntl(2) to achieve the same result.

因此,我希望从accept()返回的套接字描述符处于阻塞模式.