xref: /freebsd/lib/libpathconv/rel2abs.3 (revision 1d386b48a555f61cb7325543adbbb5c3f3407a66)
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2.\" Copyright (c) 1997 Shigio Yamaguchi. All rights reserved.
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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