Why the necessary bind function?

Question

Network administration

I read about sockets.
I see the bind function.
The description says that "the bind function is needed to bind a local address to a socket".
Ahem. What for?
There is a computer, the computer has an address. Why can't the stack somehow itself bind the address it knows to the socket?
Or is it necessary for computers that have two network cards / two addresses?

Answer 1

The description says that "the bind function is needed to bind a local address to a socket".
Ahem. What for?
There is a computer, the computer has an address. Why can't the stack somehow itself bind the address it knows to the socket?

Therefore, "address" is not only an IP address, but also a port (TCP and UDP), or a path in the file system (UNIX domain sockets) or whatever for other protocols.