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 December 13, 2025 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.Lb libpathconv 34.Ft "char *" 35.Fn rel2abs "const char *path" "const char *base" "char *result" "size_t size" 36.Sh DESCRIPTION 37The 38.Fn rel2abs 39function makes an absolute path name from a relative path name 40.Fa path 41based on a directory 42.Fa base 43and copies the resulting path name into the memory referenced by 44.Fa result . 45The 46.Fa result 47argument must refer to a buffer capable of storing at least 48.Fa size 49character 50 51The resulting path name may include symbolic links. 52.Fn abs2rel 53doesn't check whether or not any path exists. 54.Sh "RETURN VALUES" 55The 56.Fn rel2abs 57function returns absolute path name on success. 58If an error occurs, it returns 59.Dv NULL . 60.Sh EXAMPLES 61 char result[MAXPATHLEN]; 62 char *path = rel2abs("../../src/sys", "/usr/local/lib", result, MAXPATHLEN); 63 64yields: 65 66 path == "/usr/src/sys" 67 68Similarly, 69 70 path1 = rel2abs("src/sys", "/usr", result, MAXPATHLEN); 71 path2 = rel2abs(".", "/usr/src/sys", result, MAXPATHLEN); 72 73yields: 74 75 path1 == "/usr/src/sys" 76 path2 == "/usr/src/sys" 77.Sh ERRORS 78The 79.Fn rel2abs 80function may fail and set the external variable 81.Va errno 82to indicate the error. 83.Bl -tag -width Er 84.It Bq Er EINVAL 85The 86.Fa base 87directory isn't an absolute path name or the 88.Fa size 89argument is zero. 90.It Bq Er ERANGE 91The 92.Fa size 93argument is greater than zero but smaller than the length of the pathname plus 1 94.El 95.Sh SEE ALSO 96.Xr abs2rel 3 97.Sh AUTHORS 98.An Shigio Yamaguchi (shigio@tamacom.com) 99