how to know the TCP buffer size dynamically

Is it possible to know the TCP buffer size dynamically on windows.I set the TCP buffer size using SO_SNDBUF,SO_RECVBUF and also can check its allocated buffer size using getsockopt(). But I wanted to know how to get the available buffer size so that if buffer size goes beyond I can take some action.Any utility or api will be equally useful. My question is specific to windows.Though of anyone knows anything about linux it can also be useful to 开发者_开发百科know for me to get any any parallel.

Buffers are used asynchronously by the kernel. You can not control them. Moreover, the underlying implementation can ignore your SO_SNDBUF/SO_RECVBUF requests, or choose to provide smaller/larger amounts than requested.