The call succeeds unless:
[EAFNOSUPPORT]
The specified address family is not supported on this machine.
[EFAULT]
The address sv does not specify a valid part of the process address space.
[EMFILE]
Too many descriptors are in use by this process.
[ENFILE]
The system file table is full.
[EOPNOTSUPP]
The specified protocol does not support creation of socket pairs.
[EPROTONOSUPPORT]
The specified protocol is not supported on this machine.