Linux-non-blocking socket programming handles Eagain errors

The resource temporarily Unavailable,errno code is often present in Linux for non-blocking socket receive data (Eagain), which indicates that you are using blocking operation in nonblocking mode. This error is returned when the operation is not completed, and the error does not break the socket synchronization, and the next loop will be recv. For non-blocking sockets, Eagain is not an error. On VxWorks and Windows, Eagain is named Ewouldblock.

Additionally, if EINTR is present as errno 4, the error description interrupted system call, the operation should also continue.

Finally, if the return value of recv is 0, it indicates that the connection has been disconnected and our receive operation should end.

Linux-non-blocking socket programming handles Eagain errors