Menu
Suppose the listening socket passed to accept has non-default options set on it with setsockopt. Are these options (some or all of them?) inherited by the resulting file descriptors for accepted connections?
871
No and no. The socket isn't put into listening mode until you call listen() . It must be listening in order to accept() . And, once you're listening, you cannot convert the socket to a connected socket.
In addition to binding a socket to a local address or connecting it to a destination address, application programs need a method to control the socket. For example, when using protocols that use time out and retransmission, the application program may want to obtain or set the time-out parameters.
Remarks. The setsockopt function sets the current value for a socket option associated with a socket of any type, in any state. Although options can exist at multiple protocol levels, they are always present at the uppermost socket level.
These socket options are protocol independent meaning that the protocol independent code within the kernel handles these and not particular module of any protocol. Some options apply to only certain types of sockets.
Several of the socket options are handled at lower levels of the system. While most of the socket options could be set using the setsockopt. Reference:man setsockopt And since you are mentioning only POSIX on any Linux, in general, as your scope. The accept() (Reference: man accept) does have a certain amount of discretion on what socket options should be inherited and what options to reject from the listening fd.
accept() does not modify the original socket passed to it as argument. The new socket returned by accept() does not inherit file status flags such as O_NONBLOCK,O_ASYNC from the listening socket.
So, instead of relying on the inheritance or non-inheritance of the listening socket properties(which is bound to vary across implementations and licenses), the accepted socket should be explicitly set with the desired socket options.(Best practice)
man pages and the implementation codes in your machine would be the most relevant specification for the accept() behavior.There's no common or standard specification existing across multiple variants of Linux.
116
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
