NAME

       statvfs, fstatvfs - get filesystem statistics

SYNOPSIS

       #include <sys/statvfs.h>

       int statvfs(const char *restrict path, struct statvfs *restrict buf);
       int fstatvfs(int fd, struct statvfs *buf);

DESCRIPTION

       The  function  statvfs()  returns  information  about  a  mounted filesystem.  path is the
       pathname of any file within the mounted  filesystem.   buf  is  a  pointer  to  a  statvfs
       structure defined approximately as follows:

           struct statvfs {
               unsigned long  f_bsize;    /* Filesystem block size */
               unsigned long  f_frsize;   /* Fragment size */
               fsblkcnt_t     f_blocks;   /* Size of fs in f_frsize units */
               fsblkcnt_t     f_bfree;    /* Number of free blocks */
               fsblkcnt_t     f_bavail;   /* Number of free blocks for
                                             unprivileged users */
               fsfilcnt_t     f_files;    /* Number of inodes */
               fsfilcnt_t     f_ffree;    /* Number of free inodes */
               fsfilcnt_t     f_favail;   /* Number of free inodes for
                                             unprivileged users */
               unsigned long  f_fsid;     /* Filesystem ID */
               unsigned long  f_flag;     /* Mount flags */
               unsigned long  f_namemax;  /* Maximum filename length */
           };

       Here  the  types  fsblkcnt_t and fsfilcnt_t are defined in <sys/types.h>.  Both used to be
       unsigned long.

       The field f_flag is a bit mask indicating various options that were employed when mounting
       this filesystem.  It contains zero or more of the following flags:

       ST_MANDLOCK
              Mandatory locking is permitted on the filesystem (see fcntl(2)).

       ST_NOATIME
              Do not update access times; see mount(2).

       ST_NODEV
              Disallow access to device special files on this filesystem.

       ST_NODIRATIME
              Do not update directory access times; see mount(2).

       ST_NOEXEC
              Execution of programs is disallowed on this filesystem.

       ST_NOSUID
              The  set-user-ID  and set-group-ID bits are ignored by exec(3) for executable files
              on this filesystem

       ST_RDONLY
              This filesystem is mounted read-only.

       ST_RELATIME
              Update atime relative to mtime/ctime; see mount(2).

       ST_SYNCHRONOUS
              Writes are synched to the filesystem immediately (see the description of O_SYNC  in
              open(2)).

       It is unspecified whether all members of the returned struct have meaningful values on all
       filesystems.

       fstatvfs() returns the same information about an open file referenced by descriptor fd.

RETURN VALUE

       On success, zero is returned.  On error, -1 is returned, and errno is set to indicate  the
       error.

ERRORS

       EACCES (statvfs()) Search permission is denied for a component of the path prefix of path.
              (See also path_resolution(7).)

       EBADF  (fstatvfs()) fd is not a valid open file descriptor.

       EFAULT Buf or path points to an invalid address.

       EINTR  This call was interrupted by a signal; see signal(7).

       EIO    An I/O error occurred while reading from the filesystem.

       ELOOP  (statvfs()) Too many symbolic links were encountered in translating path.

       ENAMETOOLONG
              (statvfs()) path is too long.

       ENOENT (statvfs()) The file referred to by path does not exist.

       ENOMEM Insufficient kernel memory was available.

       ENOSYS The filesystem does not support this call.

       ENOTDIR
              (statvfs()) A component of the path prefix of path is not a directory.

       EOVERFLOW
              Some values were too large to be represented in the returned struct.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌───────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │Interface                                                      │ Attribute     │ Value   │
       ├───────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │statvfs(), fstatvfs()                                          │ Thread safety │ MT-Safe │
       └───────────────────────────────────────────────────────────────┴───────────────┴─────────┘

CONFORMING TO

       POSIX.1-2001, POSIX.1-2008.

       Only the ST_NOSUID and ST_RDONLY flags of the f_flag field are specified in  POSIX.1.   To
       obtain definitions of the remaining flags, one must define _GNU_SOURCE.

NOTES

       The Linux kernel has system calls statfs(2) and fstatfs(2) to support this library call.

       In  glibc  versions  before  2.13,  statvfs()  populated  the  bits of the f_flag field by
       scanning the mount options shown in /proc/mounts.  However, starting  with  Linux  2.6.36,
       the  underlying  statfs(2)  system call provides the necessary information via the f_flags
       field, and since glibc version 2.13, the statvfs() function will use information from that
       field rather than scanning /proc/mounts.

       The glibc implementations of

           pathconf(path, _PC_REC_XFER_ALIGN);
           pathconf(path, _PC_ALLOC_SIZE_MIN);
           pathconf(path, _PC_REC_MIN_XFER_SIZE);

       respectively  use  the  f_frsize,  f_frsize,  and  f_bsize  fields  returned  by a call to
       statvfs() with the argument path.

SEE ALSO

       statfs(2)

COLOPHON

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