redhat man page for gethostname

GETHOSTNAME(2)						     Linux Programmer's Manual						    GETHOSTNAME(2)

NAME
       gethostname, sethostname - get/set host name

SYNOPSIS
       #include <unistd.h>

       int gethostname(char *name, size_t len);
       int sethostname(const char *name, size_t len);

DESCRIPTION
       These  functions  are  used to access or to change the host name of the current processor.  The gethostname() function returns a NUL-termi-
       nated hostname (set earlier by sethostname()) in the array name that has a length of len bytes.	In case the NUL-terminated  hostname  does
       not fit, no error is returned, but the hostname is truncated. It is unspecified whether the truncated hostname will be NUL-terminated.

RETURN VALUE
       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

ERRORS
       EINVAL len  is negative or, for sethostname, len is larger than the maximum allowed size, or, for gethostname on Linux/i386, len is smaller
	      than the actual size.  (In this last case glibc 2.1 uses ENAMETOOLONG.)

       EPERM  For sethostname, the caller was not the superuser.

       EFAULT name is an invalid address.

CONFORMING TO
       SVr4, 4.4BSD  (this function first appeared in 4.2BSD).	POSIX 1003.1-2001 specifies gethostname but not sethostname.

BUGS
       For many Linux kernel / libc combinations gethostname will return an error instead of returning a truncated hostname.

NOTES
       SUSv2 guarantees that `Host names are limited to 255 bytes'.  POSIX 1003.1-2001 guarantees that `Host names (not including the  terminating
       NUL) are limited to HOST_NAME_MAX bytes'.

SEE ALSO
       getdomainname(2), setdomainname(2), uname(2)

Linux 2.5.0							    2001-12-15							    GETHOSTNAME(2)