The gethostname() function returns the standard host name for the current processor, as previously set by sethostname(). The namelen argument specifies the size of the array pointed to by name. The returned name
is null-terminated unless insufficient space is provided.
The sethostname() function sets the name of the host machine to be name, which has length namelen. This call is restricted to the superuser and is normally used only when the system is bootstrapped.
Host names are limited to MAXHOSTNAMELEN characters, currently 256, defined in the <netdb.h> header.