.\" Copyright (c) 1983, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)gethostname.3 8.1 (Berkeley) 6/4/93 .\" $FreeBSD: src/lib/libc/gen/gethostname.3,v 1.17 2007/01/09 00:27:54 imp Exp $ .\" .Dd August 18, 2003 .Dt GETHOSTNAME 3 .Os .Sh NAME .Nm gethostname , .Nm sethostname .Nd get/set name of current host .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In unistd.h .Ft int .Fn gethostname "char *name" "size_t namelen" .Ft int .Fn sethostname "const char *name" "int namelen" .Sh DESCRIPTION The .Fn gethostname function returns the standard host name for the current processor, as previously set by .Fn sethostname . The .Fa namelen argument specifies the size of the .Fa name array. The returned name is null-terminated, unless insufficient space is provided. .Pp The .Fn sethostname function sets the name of the host machine to be .Fa name , which has length .Fa namelen . This call is restricted to the super-user and is normally used only when the system is bootstrapped. .Pp Host names are limited in length to .Brq Dv sysconf(_SC_HOST_NAME_MAX) characters, not including the trailing null, currently 255. .Sh RETURN VALUES .Rv -std .Sh ERRORS The following errors may be returned by these calls: .Bl -tag -width Er .It Bq Er EFAULT The .Fa name or .Fa namelen argument gave an invalid address. .It Bq Er ENAMETOOLONG The current host name is longer than .Fa namelen . (For .Fn gethostname only.) .It Bq Er EPERM The caller tried to set the host name and was not the super-user. .El .Sh SEE ALSO .Xr sysconf 3 , .Xr sysctl 3 .Sh STANDARDS The .Fn gethostname function conforms to .St -p1003.1-2001 . Callers should be aware that .Brq Dv sysconf(_SC_HOST_NAME_MAX) may be variable or infinite, but is guaranteed to be no less than .Brq Dv _POSIX_HOST_NAME_MAX . On older systems, this limit was defined in the non-standard header .In sys/param.h as .Dv MAXHOSTNAMELEN , and counted the terminating null. The .Fn sethostname function and the error returns for .Fn gethostname are not standardized. .Sh HISTORY The .Fn gethostname function appeared in .Bx 4.2 . The .Fa namelen argument to .Fn gethostname was changed to .Vt size_t in .Fx 5.2 for alignment with .St -p1003.1-2001 .