b6cbf7203b
This patch imports the unmodified current version of NetBSD libc. The NetBSD includes are in /nbsd_include, while the libc code itself is split between lib/nbsd_libc and common/lib/libc.
191 lines
5.5 KiB
Groff
191 lines
5.5 KiB
Groff
.\" $NetBSD: pathconf.2,v 1.27 2010/07/26 12:30:16 njoly Exp $
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.\"
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.\" Copyright (c) 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)pathconf.2 8.1 (Berkeley) 6/4/93
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.\"
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.Dd July 26, 2010
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.Dt PATHCONF 2
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.Os
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.Sh NAME
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.Nm pathconf ,
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.Nm fpathconf
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.Nd get configurable pathname variables
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In unistd.h
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.Ft long
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.Fn pathconf "const char *path" "int name"
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.Ft long
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.Fn fpathconf "int fd" "int name"
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.Sh DESCRIPTION
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The
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.Fn pathconf
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and
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.Fn fpathconf
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functions provide a method for applications to determine the current
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value of a configurable system limit or option variable associated
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with a pathname or file descriptor.
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.Pp
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For
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.Nm pathconf ,
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the
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.Fa path
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argument is the name of a file or directory.
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For
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.Nm fpathconf ,
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the
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.Fa fd
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argument is an open file descriptor.
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The
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.Fa name
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argument specifies the system variable to be queried.
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Symbolic constants for each name value are found in the
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.In unistd.h
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header.
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.Pp
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The available values are as follows:
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.Pp
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.Bl -tag -width "123456"
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.It Li _PC_LINK_MAX
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The maximum file link count.
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.It Li _PC_MAX_CANON
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The maximum number of bytes in terminal canonical input line.
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.It Li _PC_MAX_INPUT
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The minimum maximum number of bytes for which space is available in
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a terminal input queue.
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.It Li _PC_NAME_MAX
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The maximum number of bytes in a filename,
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not including a terminating null character.
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.It Li _PC_PATH_MAX
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The maximum number of bytes in a pathname,
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including the terminating null character.
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.It Li _PC_PIPE_BUF
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The maximum number of bytes which will be written atomically to a pipe.
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.It Li _PC_CHOWN_RESTRICTED
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Return 1 if appropriate privileges are required for the
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.Xr chown 2
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system call, otherwise 0.
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.It Li _PC_NO_TRUNC
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Return 0 if filenames longer than
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.Brq Dv NAME_MAX
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are silently truncated, or non-zero if an error is generated when
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.Brq Dv NAME_MAX
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is exceeded.
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.It Li _PC_VDISABLE
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Returns the terminal character disabling value.
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.It Li _PC_SYNC_IO
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Returns 1 if synchronized I/O is supported, otherwise 0.
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.It Li _PC_FILESIZEBITS
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If the maximum size file that could ever exist on the mounted file system is
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.Dv maxsize ,
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then the returned value is 2 plus the floor of the base 2 logarithm of
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.Dv maxsize .
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.It Li _PC_SYMLINK_MAX
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The maximum number of bytes in a symbolic link.
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.It Li _PC_2_SYMLINKS
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When referring to a directory the system supports the creation of symbolic
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links within that directory; for nondirectory files, the meaning of
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.Dv {_PC_2_SYMLINKS}
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is undefined.
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.El
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.Sh RETURN VALUES
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If the call to
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.Nm pathconf
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or
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.Nm fpathconf
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is not successful, \-1 is returned and
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.Va errno
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is set appropriately.
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Otherwise, if the variable is associated with functionality that does
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not have a limit in the system, \-1 is returned and
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.Va errno
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is not modified.
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Otherwise, the current variable value is returned.
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.Sh ERRORS
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If any of the following conditions occur, the
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.Nm pathconf
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and
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.Nm fpathconf
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functions shall return \-1 and set
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.Va errno
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to the corresponding value.
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.Bl -tag -width Er
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.It Bq Er EINVAL
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The value of the
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.Fa name
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argument is invalid, or
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the implementation does not support an association of the variable
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name with the associated file.
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.El
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.Pp
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.Fn pathconf
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will fail if:
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.Bl -tag -width ENAMETOOLONGAA
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.It Bq Er EACCES
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Search permission is denied for a component of the path prefix.
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.It Bq Er EIO
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An I/O error occurred while reading from or writing to the file system.
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.It Bq Er ELOOP
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Too many symbolic links were encountered in translating the pathname.
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.It Bq Er ENAMETOOLONG
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A component of a pathname exceeded 255 characters,
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or an entire path name exceeded 1023 characters.
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.It Bq Er ENOENT
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The named file does not exist.
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.It Bq Er ENOTDIR
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A component of the path prefix is not a directory.
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.El
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.Pp
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.Fn fpathconf
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will fail if:
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.Bl -tag -width [EFAULT]
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.It Bq Er EBADF
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.Fa fd
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is not a valid open file descriptor.
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.It Bq Er EIO
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An I/O error occurred while reading from or writing to the file system.
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.El
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.Sh SEE ALSO
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.Xr sysctl 3
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.Sh STANDARDS
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The
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.Fn pathconf
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and
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.Fn fpathconf
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functions conform to
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.St -p1003.1-90 .
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.Sh HISTORY
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The
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.Nm pathconf
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and
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.Nm fpathconf
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functions first appeared in
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.Bx 4.4 .
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