psock_close() and net_close() are internal OS functions and should not set the errno variable.
psock_ioctl() and netdev_ioctl() are internal OS functions and should not set the errno variable.
net_dupsd() and net_dupsd2() are internal OS functions and should not set the errno variable.
net/ and fs/: net_vfcntl(), file_fcntl(), file_dup(), and file_dup2() are all internal OS interfaces and should not modify the errno value.
User-space networking stack API allows user-space daemon to
provide TCP/IP stack implementation for NuttX network.
Main use for this is to allow use and seamless integration of
HW-provided TCP/IP stacks to NuttX.
For example, user-space daemon can translate /dev/usrsock
API requests to HW TCP/IP API requests while rest of the
user-space can access standard socket API, with socket
descriptors that can be used with NuttX system calls.
