mirror of https://github.com/mkerrisk/man-pages
255 lines
6.8 KiB
Groff
255 lines
6.8 KiB
Groff
.\" Copyright (C) 2003 Andries Brouwer (aeb@cwi.nl)
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.\" Modified 2003-08-17 by Walter Harms
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.\" Modified 2004-06-23 by Michael Kerrisk <mtk.manpages@gmail.com>
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.\"
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.TH STATFS 2 2004-06-23 "Linux" "Linux Programmer's Manual"
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.SH NAME
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statfs, fstatfs \- get file system statistics
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.SH SYNOPSIS
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.BR "#include <sys/vfs.h> " "/* or <sys/statfs.h> */"
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.sp
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.BI "int statfs(const char *" path ", struct statfs *" buf );
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.br
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.BI "int fstatfs(int " fd ", struct statfs *" buf );
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.SH DESCRIPTION
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The function
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.BR statfs ()
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returns information about a mounted file system.
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.I path
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is the pathname of any file within the mounted filesystem.
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.I buf
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is a pointer to a
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.I statfs
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structure defined approximately as follows:
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.RS
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.nf
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struct statfs {
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long f_type; /* type of filesystem (see below) */
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long f_bsize; /* optimal transfer block size */
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long f_blocks; /* total data blocks in file system */
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long f_bfree; /* free blocks in fs */
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long f_bavail; /* free blocks avail to non-superuser */
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long f_files; /* total file nodes in file system */
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long f_ffree; /* free file nodes in fs */
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fsid_t f_fsid; /* file system id */
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long f_namelen; /* maximum length of filenames */
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};
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File system types:
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ADFS_SUPER_MAGIC 0xadf5
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AFFS_SUPER_MAGIC 0xADFF
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BEFS_SUPER_MAGIC 0x42465331
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BFS_MAGIC 0x1BADFACE
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CIFS_MAGIC_NUMBER 0xFF534D42
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CODA_SUPER_MAGIC 0x73757245
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COH_SUPER_MAGIC 0x012FF7B7
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CRAMFS_MAGIC 0x28cd3d45
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DEVFS_SUPER_MAGIC 0x1373
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EFS_SUPER_MAGIC 0x00414A53
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EXT_SUPER_MAGIC 0x137D
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EXT2_OLD_SUPER_MAGIC 0xEF51
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EXT2_SUPER_MAGIC 0xEF53
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EXT3_SUPER_MAGIC 0xEF53
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HFS_SUPER_MAGIC 0x4244
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HPFS_SUPER_MAGIC 0xF995E849
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HUGETLBFS_MAGIC 0x958458f6
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ISOFS_SUPER_MAGIC 0x9660
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JFFS2_SUPER_MAGIC 0x72b6
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JFS_SUPER_MAGIC 0x3153464a
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MINIX_SUPER_MAGIC 0x137F /* orig. minix */
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MINIX_SUPER_MAGIC2 0x138F /* 30 char minix */
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MINIX2_SUPER_MAGIC 0x2468 /* minix V2 */
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MINIX2_SUPER_MAGIC2 0x2478 /* minix V2, 30 char names */
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MSDOS_SUPER_MAGIC 0x4d44
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NCP_SUPER_MAGIC 0x564c
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NFS_SUPER_MAGIC 0x6969
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NTFS_SB_MAGIC 0x5346544e
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OPENPROM_SUPER_MAGIC 0x9fa1
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PROC_SUPER_MAGIC 0x9fa0
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QNX4_SUPER_MAGIC 0x002f
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REISERFS_SUPER_MAGIC 0x52654973
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ROMFS_MAGIC 0x7275
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SMB_SUPER_MAGIC 0x517B
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SYSV2_SUPER_MAGIC 0x012FF7B6
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SYSV4_SUPER_MAGIC 0x012FF7B5
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TMPFS_MAGIC 0x01021994
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UDF_SUPER_MAGIC 0x15013346
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UFS_MAGIC 0x00011954
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USBDEVICE_SUPER_MAGIC 0x9fa2
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VXFS_SUPER_MAGIC 0xa501FCF5
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XENIX_SUPER_MAGIC 0x012FF7B4
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XFS_SUPER_MAGIC 0x58465342
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_XIAFS_SUPER_MAGIC 0x012FD16D
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.fi
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.RE
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.PP
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Nobody knows what
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.I f_fsid
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is supposed to contain (but see below).
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.PP
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Fields that are undefined for a particular file system are set to 0.
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.BR fstatfs ()
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returns the same information about an open file referenced by descriptor
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.IR fd .
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.SH "RETURN VALUE"
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On success, zero is returned.
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On error, \-1 is returned, and
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.I errno
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is set appropriately.
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.SH ERRORS
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.TP
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.B EACCES
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.RB ( statfs ())
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Search permission is denied for a component of the path prefix of
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.IR path .
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(See also
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.BR path_resolution (7).)
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.TP
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.B EBADF
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.RB ( fstatfs ())
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.I fd
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is not a valid open file descriptor.
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.TP
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.B EFAULT
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.I buf
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or
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.I path
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points to an invalid address.
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.TP
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.B EINTR
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This call was interrupted by a signal.
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.TP
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.B EIO
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An I/O error occurred while reading from the file system.
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.TP
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.B ELOOP
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.RB ( statfs ())
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Too many symbolic links were encountered in translating
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.IR path .
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.TP
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.B ENAMETOOLONG
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.RB ( statfs ())
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.I path
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is too long.
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.TP
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.B ENOENT
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.RB ( statfs ())
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The file referred to by
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.I path
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does not exist.
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.TP
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.B ENOMEM
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Insufficient kernel memory was available.
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.TP
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.B ENOSYS
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The file system does not support this call.
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.TP
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.B ENOTDIR
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.RB ( statfs ())
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A component of the path prefix of
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.I path
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is not a directory.
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.TP
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.B EOVERFLOW
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Some values were too large to be represented in the returned struct.
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.SH "CONFORMING TO"
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Linux specific.
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The Linux
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.BR statfs ()
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was inspired by the 4.4BSD one
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(but they do not use the same structure).
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.SH NOTES
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The kernel has system calls
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.BR statfs (),
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.BR fstatfs (),
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.BR statfs64 (),
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and
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.BR fstatfs64 ()
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to support this library call.
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Some systems only have \fI<sys/vfs.h>\fP, other systems also have
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\fI<sys/statfs.h>\fP, where the former includes the latter.
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So it seems
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including the former is the best choice.
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LSB has deprecated the library calls
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.BR statfs ()
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and
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.BR fstatfs ()
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and tells us to use
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.BR statvfs (2)
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and
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.BR fstatvfs (2)
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instead.
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.SS The f_fsid field
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Solaris, Irix and POSIX have a system call
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.BR statvfs (2)
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that returns a
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.I "struct statvfs"
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(defined in
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.IR "<sys/statvfs.h>" )
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containing an
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.I "unsigned long"
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.IR f_fsid .
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Linux, SunOS, HP-UX, 4.4BSD have a system call
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.BR statfs ()
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that returns a
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.I "struct statfs"
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(defined in
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.IR "<sys/vfs.h>" )
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containing a
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.I fsid_t
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.IR f_fsid ,
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where
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.I fsid_t
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is defined as
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.IR "struct { int val[2]; }" .
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The same holds for FreeBSD, except that it uses the include file
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.IR "<sys/mount.h>" .
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The general idea is that
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.I f_fsid
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contains some random stuff such that the pair
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.RI ( f_fsid , ino )
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uniquely determines a file.
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Some OSes use (a variation on) the device number, or the device number
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combined with the filesystem type.
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Several OSes restrict giving out the
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.I f_fsid
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field to the superuser only (and zero it for unprivileged users),
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because this field is used in the filehandle of the filesystem
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when NFS-exported, and giving it out is a security concern.
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.LP
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Under some OSes the
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.I fsid
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can be used as second parameter to the
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.BR sysfs ()
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system call.
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.SH "SEE ALSO"
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.BR stat (2),
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.BR statvfs (2),
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.BR path_resolution (7)
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