gen/devname.3

   1 .\" Copyright (c) 1993
   2 .\"     The Regents of the University of California.  All rights reserved.
   3 .\"
   4 .\" Redistribution and use in source and binary forms, with or without
   5 .\" modification, are permitted provided that the following conditions
   6 .\" are met:
   7 .\" 1. Redistributions of source code must retain the above copyright
   8 .\"    notice, this list of conditions and the following disclaimer.
   9 .\" 2. Redistributions in binary form must reproduce the above copyright
  10 .\"    notice, this list of conditions and the following disclaimer in the
  11 .\"    documentation and/or other materials provided with the distribution.
  12 .\" 3. All advertising materials mentioning features or use of this software
  13 .\"    must display the following acknowledgement:
  14 .\"     This product includes software developed by the University of
  15 .\"     California, Berkeley and its contributors.
  16 .\" 4. Neither the name of the University nor the names of its contributors
  17 .\"    may be used to endorse or promote products derived from this software
  18 .\"    without specific prior written permission.
  19 .\"
  20 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30 .\" SUCH DAMAGE.
  31 .\"
  32 .\"     @(#)devname.3   8.2 (Berkeley) 4/29/95
  33 .\" $FreeBSD: src/lib/libc/gen/devname.3,v 1.11 2001/10/01 16:08:50 ru Exp $
  34 .\"
  35 .Dd October 25, 2004
  36 .Dt DEVNAME 3
  37 .Os
  38 .Sh NAME
  39 .Nm devname ,
  40 .Nm devname_r
  41 .Nd get device name
  42 .Sh LIBRARY
  43 .Lb libc
  44 .Sh SYNOPSIS
  45 .In sys/stat.h
  46 .In stdlib.h
  47 .Ft char *
  48 .Fo devname
  49 .Fa "dev_t dev"
  50 .Fa "mode_t type"
  51 .Fc
  52 .Ft char *
  53 .Fo devname_r
  54 .Fa "dev_t dev"
  55 .Fa "mode_t type"
  56 .Fa "char *buf"
  57 .Fa "int len"
  58 .Fc
  59 .Sh DESCRIPTION
  60 The
  61 .Fn devname
  62 function returns a pointer to the name of the block or character
  63 device in
  64 .Dq Pa /dev
  65 with a device number of
  66 .Fa dev ,
  67 and a file type matching the one encoded in
  68 .Fa type
  69 which must be one of
  70 .Dv S_IFBLK
  71 or
  72 .Dv S_IFCHR .
  73 If no device matches the specified values, or no information is
  74 available, NULL is returned.
  75 .Pp
  76 The
  77 .Fn devname
  78 function uses a static buffer, which will be overwritten
  79 on subsequent calls.
  80 The
  81 .Fn devname_r
  82 functions takes a buffer and length as arguments to avoid this problem.
  83 .Pp
  84 The traditional display for applications when no device is
  85 found is the string
  86 .Dq ?? .
  87 .Sh SEE ALSO
  88 .Xr stat 2 ,
  89 .Xr dev_mkdb 8
  90 .Sh HISTORY
  91 The
  92 .Fn devname
  93 function call appeared in
  94 .Bx 4.4 .