I've used cygwin in the past few years using the MSG_MORE flag when using some socket functions but now it's not defined in cygwin\socket.h and MSG_EOR is using the value of MSG_MORE (0x8000). Above that in the socket.h file there is a comment /* MSG_EOR is not supported. We use the MSG_PARTIAL flag here */. I understand this as meaning MSG_EOR now works as MSG_MORE would and that MSG_EOR is not usable. Just want some clarification on this.