xref: /freebsd/lib/libpathconv/rel2abs.3 (revision 99aeb219cad9a5a0347ca3ffef963bb614c99eb9)
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.\" $FreeBSD$
27.\"
28.Dd August 7, 2022
29.Dt REL2ABS 3
30.Os
31.Sh NAME
32.Nm rel2abs
33.Nd make an absolute path name from a relative path name
34.Sh SYNOPSIS
35.Ft "char *"
36.Fn rel2abs "const char *path" "const char *base" "char *result" "size_t size"
37.Sh DESCRIPTION
38The
39.Fn rel2abs
40function makes an absolute path name from a relative path name
41.Fa path
42based on a directory
43.Fa base
44and copies the resulting path name into the memory referenced by
45.Fa result .
46The
47.Fa result
48argument must refer to a buffer capable of storing at least
49.Fa size
50character
51
52The resulting path name may include symbolic links.
53.Fn abs2rel
54doesn't check whether or not any path exists.
55.Sh "RETURN VALUES"
56The
57.Fn rel2abs
58function returns absolute path name on success.
59If an error occurs, it returns
60.Dv NULL .
61.Sh EXAMPLES
62    char result[MAXPATHLEN];
63    char *path = rel2abs("../../src/sys", "/usr/local/lib", result, MAXPATHLEN);
64
65yields:
66
67    path == "/usr/src/sys"
68
69Similarly,
70
71    path1 = rel2abs("src/sys", "/usr", result, MAXPATHLEN);
72    path2 = rel2abs(".", "/usr/src/sys", result, MAXPATHLEN);
73
74yields:
75
76    path1 == "/usr/src/sys"
77    path2 == "/usr/src/sys"
78.Sh ERRORS
79The
80.Fn rel2abs
81function may fail and set the external variable
82.Va errno
83to indicate the error.
84.Bl -tag -width Er
85.It Bq Er EINVAL
86The
87.Fa base
88directory isn't an absolute path name or the
89.Fa size
90argument is zero.
91.It Bq Er ERANGE
92The
93.Fa size
94argument is greater than zero but smaller than the length of the pathname plus 1
95.Sh SEE ALSO
96.Xr abs2rel 3
97.Sh AUTHORS
98.An Shigio Yamaguchi (shigio@tamacom.com)
99