What is SOL_SOCKET used for?

As it is stated in the Linux `man` page

> Use this constant as the level argument to `getsockopt` or `setsockopt` to manipulate the socket-level options described in this section

But I don't get this explanation. What is the purpose of `SOL_SOCKET`? What does it do?

When retrieving a socket option, or setting it, you specify the option name as well as the level. When level = `SOL_SOCKET`, the item will be searched for in the socket itself.

For example, suppose we want to set the socket option to reuse the address to 1 (on/true), we pass in the "level" `SOL_SOCKET` and the value we want it set to.

int value = 1;
setsockopt(mysocket, SOL_SOCKET, SO_REUSEADDR, &value, sizeof(value));

This will set the `SO_REUSEADDR` in my socket to 1.

I was stuck on this myself, the documentation is extremely cryptic. Slightly more detailed documentation here:

[To see links please register here]

`SOL_SOCKET` is the socket layer itself. It is used for options that are protocol independent.

You can read more [here][1].


[1]:

[To see links please register here]