question about the "fd_set *writefds" parameter in the select() statement
As most of you are aware, this is the prototype of the select statement (acc to man pages):
I know what to use the readfds parameter for: with this one you can see if data was written to one of your sockets. On the other hand, the writefds page that I found, states that this is to see "if any of the sockets is ready to send() data to". But what does this mean? In Windows Sockets Network Programming by Quin and Shute it says that this detects either the connected or the writable state. What is the point of this? Is it simply to check whether a socket still has a connection to a connected client and test whether is has any use writing something to that socket?
int select(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
struct timeval *timeout);
So: what does one normally use writefds for?