I think it depends what you consider an error. For example let's say I have a library that opens sockets to hosts. If I can't reach the host that isn't an err

I think it depends what you consider an error. For example let's say I have a library that opens sockets to hosts. If I can't reach the host that isn't an error and I report back a failure of that function to succeed. If I can't allocate the memory for a socket then instead of reporting a failure to connect I throw an exception for the true error.