I am trying to replicate a real time application on a windows computer to be able to debug and make changes easier, but I ran into issue with Delayed Ack. I have already disabled nagle and confirmed that it improve the speed a bit. When sending a lots of small packets, window doesn't ACK right away and delay it by 200 ms. Doing more research about it, I came across this. Problem with changing the registry value is that, it will affect the whole system rather than just the application that I am working with. Is there anyway to disable delayed ACK on window system like TCP_QUICKACK from linux using setsockopt? I tried hard coding 12, but got WSAEINVAL from WSAGetLastError.

I saw some dev on github that mentioned to use SIO_TCP_SET_ACK_FREQUENCY but I didn't see any example on how to actually use it.

So I tried doing below

#define SIO_TCP_SET_ACK_FREQUENCY _WSAIOW(IOC_VENDOR,23) 
result = WSAIoctl(sock, SIO_TCP_SET_ACK_FREQUENCY, 0, 0, info, sizeof(info), &bytes, 0, 0);

and I got WSAEFAULT as an error code. Please help!