gen/gethostname.3

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  32 .\"     @(#)gethostname.3       8.1 (Berkeley) 6/4/93
  33 .\" $FreeBSD: src/lib/libc/gen/gethostname.3,v 1.16 2004/07/03 22:30:08 ru Exp $
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  35 .Dd August 18, 2003
  36 .Dt GETHOSTNAME 3
  37 .Os
  38 .Sh NAME
  39 .Nm gethostname ,
  40 .Nm sethostname
  41 .Nd get/set name of current host
  42 .Sh LIBRARY
  43 .Lb libc
  44 .Sh SYNOPSIS
  45 .In unistd.h
  46 .Ft int
  47 .Fn gethostname "char *name" "size_t namelen"
  48 .Ft int
  49 .Fn sethostname "const char *name" "int namelen"
  50 .Sh DESCRIPTION
  51 The
  52 .Fn gethostname
  53 function
  54 returns the standard host name for the current processor, as
  55 previously set by
  56 .Fn sethostname .
  57 The
  58 .Fa namelen
  59 argument
  60 specifies the size of the
  61 .Fa name
  62 array.
  63 The returned name is null-terminated, unless insufficient space is provided.
  64 .Pp
  65 The
  66 .Fn sethostname
  67 function
  68 sets the name of the host machine to be
  69 .Fa name ,
  70 which has length
  71 .Fa namelen .
  72 This call is restricted to the super-user and
  73 is normally used only when the system is bootstrapped.
  74 .Pp
  75 Host names are limited to
  76 .Brq Dv HOST_NAME_MAX
  77 characters, not including the trailing null, currently 255.
  78 .Sh RETURN VALUES
  79 .Rv -std
  80 .Sh ERRORS
  81 The following errors may be returned by these calls:
  82 .Bl -tag -width Er
  83 .It Bq Er EFAULT
  84 The
  85 .Fa name
  86 or
  87 .Fa namelen
  88 argument gave an
  89 invalid address.
  90 .It Bq Er ENAMETOOLONG
  91 The current host name is longer than
  92 .Fa namelen .
  93 (For
  94 .Fn gethostname
  95 only.)
  96 .It Bq Er EPERM
  97 The caller tried to set the host name and was not the super-user.
  98 .El
  99 .Sh SEE ALSO
 100 .Xr sysconf 3 ,
 101 .Xr sysctl 3
 102 .Sh STANDARDS
 103 The
 104 .Fn gethostname
 105 function conforms to
 106 .St -p1003.1-2001 .
 107 Callers should be aware that
 108 .Brq Dv HOST_NAME_MAX
 109 may be variable or infinite, but is guaranteed to be no less than
 110 .Brq Dv _POSIX_HOST_NAME_MAX .
 111 On older systems, this limit was defined in the non-standard header
 112 .In sys/param.h
 113 as
 114 .Dv MAXHOSTNAMELEN ,
 115 and counted the terminating null.
 116 The
 117 .Fn sethostname
 118 function and the error returns for
 119 .Fn gethostname
 120 are not standardized.
 121 .Sh HISTORY
 122 The
 123 .Fn gethostname
 124 function appeared in
 125 .Bx 4.2 .
 126 The
 127 .Fa namelen
 128 argument to
 129 .Fn gethostname
 130 was changed to
 131 .Vt size_t
 132 in
 133 .Fx 5.2
 134 for alignment with
 135 .St -p1003.1-2001 .