gen/FreeBSD/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 .Ft char *
  32 .Fo dirname_r
  33 .Fa "const char *path" "char *dname"
  34 .Fc
  35 .Sh DESCRIPTION
  36 The
  37 .Fn dirname
  38 function is the converse of
  39 .Xr basename 3 ;
  40 it returns a pointer to the parent directory of the pathname pointed to by
  41 .Fa path .
  42 Any trailing
  43 .Sq \&/
  44 characters are not counted as part of the directory
  45 name.
  46 If
  47 .Fa path
  48 is a null pointer, the empty string, or contains no
  49 .Sq \&/
  50 characters,
  51 .Fn dirname
  52 returns a pointer to the string
  53 .Qq \&. ,
  54 signifying the current directory.
  55 .Sh IMPLEMENTATION NOTES
  56 The
  57 .Fn dirname
  58 function
  59 returns a pointer to internal storage space allocated on the first call
  60 that will be overwritten
  61 by subsequent calls.
  62 .Fn dirname_r
  63 is therefore preferred for threaded applications.
  64 .Pp
  65 Other vendor implementations of
  66 .Fn dirname
  67 may modify the contents of the string passed to
  68 .Fn dirname ;
  69 if portability is desired,
  70 this should be taken into account when writing code which calls this function.
  71 .Sh LEGACY SYNOPSIS
  72 .Fd #include <libgen.h>
  73 .Pp
  74 .Ft char *
  75 .br
  76 .Fo dirname
  77 .Fa "const char *path"
  78 .Fc ;
  79 .Pp
  80 In legacy mode,
  81 .Fa path
  82 will not be changed.
  83 .Sh RETURN VALUES
  84 On successful completion,
  85 .Fn dirname
  86 returns a pointer to the parent directory of
  87 .Fa path .
  88 .Pp
  89 If
  90 .Fn dirname
  91 fails, a null pointer is returned and the global variable
  92 .Va errno
  93 is set to indicate the error.
  94 .Sh ERRORS
  95 The following error codes may be set in
  96 .Va errno :
  97 .Bl -tag -width Er
  98 .It Bq Er ENAMETOOLONG
  99 The path component to be returned was larger than
 100 .Dv MAXPATHLEN .
 101 .It Bq Er ENOMEM
 102 The static buffer used for storing the path in
 103 .Fn dirname
 104 could not be allocated.
 105 .El
 106 .Sh SEE ALSO
 107 .Xr basename 1 ,
 108 .Xr dirname 1 ,
 109 .Xr basename 3 ,
 110 .Xr compat 5
 111 .Sh STANDARDS
 112 The
 113 .Fn dirname
 114 function conforms to
 115 .St -xpg4.2 .
 116 .Sh HISTORY
 117 The
 118 .Fn dirname
 119 function first appeared in
 120 .Ox 2.2
 121 and
 122 .Fx 4.2 .
 123 The
 124 .Fn dirname_r
 125 function first appeared in OS X 10.12.
 126 .Sh AUTHORS
 127 .An "Todd C. Miller"