gen/dirname.3

   1 .\" $OpenBSD: dirname.3,v 1.17 2007/05/31 19:19:28 jmc Exp $
   2 .\"
   3 .\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
   4 .\"
   5 .\" Permission to use, copy, modify, and distribute this software for any
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   9 .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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  17 .\" $FreeBSD: src/lib/libc/gen/dirname.3,v 1.10 2008/11/03 05:19:45 delphij Exp $
  18 .\"
  19 .Dd October 12, 2006
  20 .Dt DIRNAME 3
  21 .Os
  22 .Sh NAME
  23 .Nm dirname
  24 .Nd extract the directory part of a pathname
  25 .Sh SYNOPSIS
  26 .In libgen.h
  27 .Ft char *
  28 .Fo dirname
  29 .Fa "char *path"
  30 .Fc
  31 .Sh DESCRIPTION
  32 The
  33 .Fn dirname
  34 function is the converse of
  35 .Xr basename 3 ;
  36 it returns a pointer to the parent directory of the pathname pointed to by
  37 .Fa path .
  38 Any trailing
  39 .Sq \&/
  40 characters are not counted as part of the directory
  41 name.
  42 If
  43 .Fa path
  44 is a null pointer, the empty string, or contains no
  45 .Sq \&/
  46 characters,
  47 .Fn dirname
  48 returns a pointer to the string
  49 .Qq \&. ,
  50 signifying the current directory.
  51 .Sh IMPLEMENTATION NOTES
  52 The
  53 .Fn dirname
  54 function
  55 returns a pointer to internal storage space allocated on the first call
  56 that will be overwritten
  57 by subsequent calls.
  58 .Pp
  59 Other vendor implementations of
  60 .Fn dirname
  61 may modify the contents of the string passed to
  62 .Fn dirname ;
  63 if portability is desired,
  64 this should be taken into account when writing code which calls this function.
  65 .Sh LEGACY SYNOPSIS
  66 .Fd #include <libgen.h>
  67 .Pp
  68 .Ft char *
  69 .br
  70 .Fo dirname
  71 .Fa "const char *path"
  72 .Fc ;
  73 .Pp
  74 In legacy mode,
  75 .Fa path
  76 will not be changed.
  77 .Sh RETURN VALUES
  78 On successful completion,
  79 .Fn dirname
  80 returns a pointer to the parent directory of
  81 .Fa path .
  82 .Pp
  83 If
  84 .Fn dirname
  85 fails, a null pointer is returned and the global variable
  86 .Va errno
  87 is set to indicate the error.
  88 .Sh ERRORS
  89 The following error codes may be set in
  90 .Va errno :
  91 .Bl -tag -width Er
  92 .It Bq Er ENAMETOOLONG
  93 The path component to be returned was larger than
  94 .Dv MAXPATHLEN .
  95 .El
  96 .Sh SEE ALSO
  97 .Xr basename 1 ,
  98 .Xr dirname 1 ,
  99 .Xr basename 3 ,
 100 .Xr compat 5
 101 .Sh STANDARDS
 102 The
 103 .Fn dirname
 104 function conforms to
 105 .St -xpg4.2 .
 106 .Sh HISTORY
 107 The
 108 .Fn dirname
 109 function first appeared in
 110 .Ox 2.2
 111 and
 112 .Fx 4.2 .
 113 .Sh AUTHORS
 114 .An "Todd C. Miller"