stdlib/realpath.3

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  35 .\"     @(#)realpath.3  8.2 (Berkeley) 2/16/94
  36 .\" $FreeBSD: src/lib/libc/stdlib/realpath.3,v 1.13 2003/03/27 20:48:53 fjoe Exp $
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  38 .Dd February 16, 1994
  39 .Dt REALPATH 3
  40 .Os
  41 .Sh NAME
  42 .Nm realpath
  43 .Nd returns the canonicalized absolute pathname
  44 .Sh LIBRARY
  45 .Lb libc
  46 .Sh SYNOPSIS
  47 .In stdlib.h
  48 .Ft "char *"
  49 .Fo realpath
  50 .Fa "const char *restrict file_name"
  51 .Fa "char *restrict resolved_name"
  52 .Fc
  53 .Sh DESCRIPTION
  54 The
  55 .Fn realpath
  56 function resolves all symbolic links, extra
  57 .Dq /
  58 characters, and references to
  59 .Pa /./
  60 and
  61 .Pa /../
  62 in
  63 .Fa file_name ,
  64 and copies the resulting absolute pathname into
  65 the memory referenced by
  66 .Fa resolved_name .
  67 The
  68 .Fa resolved_name
  69 argument
  70 .Em must
  71 refer to a buffer capable of storing at least
  72 .Dv PATH_MAX
  73 characters.
  74 .Pp
  75 The
  76 .Fn realpath
  77 function will resolve both absolute and relative paths
  78 and return the absolute pathname corresponding to
  79 .Fa file_name .
  80 All components of
  81 .Fa file_name
  82 must exist when
  83 .Fn realpath
  84 is called.
  85 .Sh "RETURN VALUES"
  86 The
  87 .Fn realpath
  88 function returns
  89 .Fa resolved_name
  90 on success.
  91 If an error occurs,
  92 .Fn realpath
  93 returns
  94 .Dv NULL
  95 and
  96 .Fa resolved_name
  97 contains the pathname which caused the problem.
  98 .Sh ERRORS
  99 The function
 100 .Fn realpath
 101 may fail and set the external variable
 102 .Va errno
 103 for any of the errors specified for the library functions
 104 .Xr lstat 2 ,
 105 .Xr readlink 2 ,
 106 and
 107 .Xr getcwd 3 .
 108 .Sh CAVEATS
 109 This implementation of
 110 .Fn realpath
 111 differs slightly from the Solaris implementation.
 112 The
 113 .Bx 4.4
 114 version always returns absolute pathnames,
 115 whereas the Solaris implementation will,
 116 under certain circumstances, return a relative
 117 .Fa resolved_name
 118 when given a relative
 119 .Fa file_name .
 120 .Sh LEGACY SYNOPSIS
 121 .Fd #include <sys/param.h>
 122 .Fd #include <stdlib.h>
 123 .Pp
 124 The include file
 125 .In sys/param.h
 126 is necessary.
 127 .Sh LEGACY DESCRIPTION
 128 In legacy mode,
 129 the last component of
 130 .Fa file_name
 131 does not need to exist when
 132 .Fn realpath
 133 is called.
 134 .Sh "SEE ALSO"
 135 .Xr getcwd 3 ,
 136 .Xr compat 5
 137 .Sh HISTORY
 138 The
 139 .Fn realpath
 140 function first appeared in
 141 .Bx 4.4 .