gen/dirname.3

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   2 .\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
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  27 .\" $OpenBSD: dirname.3,v 1.9 2000/04/18 03:01:25 aaron Exp $
  28 .\" $FreeBSD: src/lib/libc/gen/dirname.3,v 1.8 2004/07/02 23:52:10 ru Exp $
  29 .\"
  30 .Dd August 17, 1997
  31 .Dt DIRNAME 3
  32 .Os
  33 .Sh NAME
  34 .Nm dirname
  35 .Nd extract the directory part of a pathname
  36 .Sh SYNOPSIS
  37 .In libgen.h
  38 .Ft char *
  39 .Fo dirname
  40 .Fa "char *path"
  41 .Fc
  42 .Sh DESCRIPTION
  43 The
  44 .Fn dirname
  45 function
  46 is the converse of
  47 .Xr basename 3 ;
  48 it returns a pointer to the parent directory of the pathname pointed to by
  49 .Fa path .
  50 Any trailing
  51 .Sq \&/
  52 characters are not counted as part of the directory
  53 name.
  54 If
  55 .Fa path
  56 is a null pointer, the empty string, or contains no
  57 .Sq \&/
  58 characters,
  59 .Fn dirname
  60 returns a pointer to the string
  61 .Qq \&. ,
  62 signifying the current directory.
  63 .Sh RETURN VALUES
  64 On successful completion,
  65 .Fn dirname
  66 returns a pointer to the parent directory of
  67 .Fa path .
  68 .Pp
  69 If
  70 .Fn dirname
  71 fails, a null pointer is returned and the global variable
  72 .Va errno
  73 is set to indicate the error.
  74 .Sh ERRORS
  75 The following error codes may be set in
  76 .Va errno :
  77 .Bl -tag -width Er
  78 .It Bq Er ENAMETOOLONG
  79 The path component to be returned was larger than
  80 .Dv MAXPATHLEN .
  81 .El
  82 .Sh WARNINGS
  83 The
  84 .Fn dirname
  85 function
  86 returns a pointer to internal static storage space that will be overwritten
  87 by subsequent calls (each function has its own separate storage).
  88 .Pp
  89 Other vendor implementations of
  90 .Fn dirname
  91 may modify the contents of the string passed to
  92 .Fn dirname ;
  93 if portability is desired,
  94 this should be taken into account when writing code which calls this function.
  95 .Sh LEGACY SYNOPSIS
  96 .Fd #include <libgen.h>
  97 .Pp
  98 .Ft char *
  99 .br
 100 .Fo dirname
 101 .Fa "const char *path"
 102 .Fc ;
 103 .Pp
 104 In legacy mode,
 105 .Fa path
 106 will not be changed.
 107 .Sh SEE ALSO
 108 .Xr basename 1 ,
 109 .Xr dirname 1 ,
 110 .Xr basename 3 ,
 111 .Xr compat 5
 112 .Sh STANDARDS
 113 The
 114 .Fn dirname
 115 function conforms to
 116 .St -xpg4.2 .
 117 .Sh HISTORY
 118 The
 119 .Fn dirname
 120 function first appeared in
 121 .Ox 2.2
 122 and
 123 .Fx 4.2 .
 124 .Sh AUTHORS
 125 .An "Todd C. Miller" Aq Todd.Miller@courtesan.com