I have a C++ program which reads frames from a high speed camera and write each frame to a socket (unix socket). Each write is of 4096 bytes. Each frame is roughly 5MB. ( There is no guarantee that frame size would be constant but it is always a multiple of 4096 bytes. )

There is a python script which reads from the socket : 10 \* 4096 bytes at each call of `recv`. Often I get unexpected behavior which I think boils down to understand the following about the sockets. I believe both of my programs are `write`/`recv`ing in blocking mode.

* Can I write whole frame in one go (write call with 5MB of data)? Is it recommended? Speed is major concern here.
* If python client fails to read or read slowly than write, does it mean that after some time write operation on socket would not add to buffer? Or, would they overwrite the buffer? If no-one is reading the socket, I'd not mind overwriting the buffer.

Ideally, I'd like my application to write to socket as fast as possibly. If no one is reading the data, then overwriting is fine. If someone is reading the data from socket but not reading fast enough, I'd like to store all data in buffer. Then how can I force my socket to increase the buffer size when reading is slow?