<gio/gnetworking.h> header can be included to get
various low-level networking-related system headers, automatically
taking care of certain portability issues for you.
This can be used, for example, if you want to call
on a GSocket.
Note that while WinSock has many of the same APIs as the traditional UNIX socket API, most of them behave at least slightly differently (particularly with respect to error handling). If you want your code to work under both UNIX and Windows, you will need to take these differences into account.
Also, under GNU libc, certain non-portable functions are only visible
in the headers if you define
_GNU_SOURCE before including them. Note
that this symbol must be defined before including any headers, or it
may not take effect.
Initializes the platform networking libraries (eg, on Windows, this
WSAStartup()). GLib will call this itself if it is needed, so
you only need to call it if you directly call system networking
functions (without calling any GLib networking functions first).