gethostname.2

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)gethostname.2	8.1	9/11/90
.TH gethostname 2
.SH Name
gethostname, sethostname \- get or set the name of the current host
.SH Syntax
.br
.B gethostname(\fIname, namelen\fP)
.br
.B char *\fIname\fP;
.br
.B int \fInamelen\fP;
.sp
.br
.B sethostname(\fIname, namelen\fP)
.br
.B char *\fIname\fP;
.br
.B int \fInamelen\fP;
.SH Description
.NXR "gethostname system call"
.NXR "sethostname system call"
.NXR "host name" "getting"
.NXR "host name" "setting"
The
.PN gethostname
system call
returns the standard host name for the current processor, as
previously set by
.PN sethostname. 
The 
.I namelen
parameter specifies the size of the 
.I name
array.  The returned name is null-terminated unless insufficient
space is provided.
.PP
The
.PN sethostname
system call
sets the name of the host machine to be
.IR name ,
which has length
.IR namelen .
This call is restricted to the superuser and
is normally used only when the system is bootstrapped.
.SH Return Values
.IP " 0" 5
If the call succeeds, it returns a value of zero.
.IP \-1
If the call fails, a value of \-1 is returned and an error code is
placed in the global location, \fIerrno\fP.
.SH Restrictions
Host names are limited to 31 characters and may contain only lower 
case ASCII characters a to z, numbers 0 to 9, dashes (\-), 
underscores (_), and periods (.).
.SH Diagnostics
The
.PN gethostname
system call fails under the following condition:
.IP [EFAULT] 15
The \fIname\fP parameter points outside the process's allocated address space. 
.PP
The 
.PN sethostname 
system call fails under the following conditions:
.IP [EPERM] 15
The caller is not the superuser.
.IP [EINVAL]
The \fIname\fR or \fInamelen\fR parameter is an invalid address.
.SH See Also
hostname(1), gethostid(2)