xref: /freebsd/lib/libpathconv/rel2abs.3 (revision f5463265955b829775bbb32e1fd0bc11dafc36ce)
1.\"
2.\" Copyright (c) 1997 Shigio Yamaguchi. All rights reserved.
3.\" Copyright (c) 1999 Tama Communications Corporation. All rights reserved.
4.\"
5.\" Redistribution and use in source and binary forms, with or without
6.\" modification, are permitted provided that the following conditions
7.\" are met:
8.\" 1. Redistributions of source code must retain the above copyright
9.\"    notice, this list of conditions and the following disclaimer.
10.\" 2. Redistributions in binary form must reproduce the above copyright
11.\"    notice, this list of conditions and the following disclaimer in the
12.\"    documentation and/or other materials provided with the distribution.
13.\"
14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24.\" SUCH DAMAGE.
25.\"
26.Dd August 7, 2022
27.Dt REL2ABS 3
28.Os
29.Sh NAME
30.Nm rel2abs
31.Nd make an absolute path name from a relative path name
32.Sh SYNOPSIS
33.Ft "char *"
34.Fn rel2abs "const char *path" "const char *base" "char *result" "size_t size"
35.Sh DESCRIPTION
36The
37.Fn rel2abs
38function makes an absolute path name from a relative path name
39.Fa path
40based on a directory
41.Fa base
42and copies the resulting path name into the memory referenced by
43.Fa result .
44The
45.Fa result
46argument must refer to a buffer capable of storing at least
47.Fa size
48character
49
50The resulting path name may include symbolic links.
51.Fn abs2rel
52doesn't check whether or not any path exists.
53.Sh "RETURN VALUES"
54The
55.Fn rel2abs
56function returns absolute path name on success.
57If an error occurs, it returns
58.Dv NULL .
59.Sh EXAMPLES
60    char result[MAXPATHLEN];
61    char *path = rel2abs("../../src/sys", "/usr/local/lib", result, MAXPATHLEN);
62
63yields:
64
65    path == "/usr/src/sys"
66
67Similarly,
68
69    path1 = rel2abs("src/sys", "/usr", result, MAXPATHLEN);
70    path2 = rel2abs(".", "/usr/src/sys", result, MAXPATHLEN);
71
72yields:
73
74    path1 == "/usr/src/sys"
75    path2 == "/usr/src/sys"
76.Sh ERRORS
77The
78.Fn rel2abs
79function may fail and set the external variable
80.Va errno
81to indicate the error.
82.Bl -tag -width Er
83.It Bq Er EINVAL
84The
85.Fa base
86directory isn't an absolute path name or the
87.Fa size
88argument is zero.
89.It Bq Er ERANGE
90The
91.Fa size
92argument is greater than zero but smaller than the length of the pathname plus 1
93.Sh SEE ALSO
94.Xr abs2rel 3
95.Sh AUTHORS
96.An Shigio Yamaguchi (shigio@tamacom.com)
97