That documentation says "[EINTR] A signal was caught during open().", and the documentation there for sigaction with SA_RESTART says "If set, and a function specified as interruptible is interrupted by this signal, the function shall restart and shall not fail with [EINTR] unless otherwise specified.", so as long as all signals were installed with SA_RESTART (which is probably the most common case since nobody likes dealing with EINTR), open() should never fail with EINTR.