statfs, fstatfs, ustat - Get file system statistics
struct statfs **buffer ); int fstatfs
struct statfs *buffer ); #include <sys/types.h> #include
struct ustat *buffer );
Specifies any file within the mounted file system. Specifies a file
descriptor obtained by a successful open() or fcntl() function. Points
to a statfs buffer to hold the returned information for the statfs() or
fstatfs() function; points to a ustat buffer to hold the returned
information for the ustat() function. Specifies the ID of the device.
It corresponds to the st_rdev member of the structure returned by the
The statfs() and fstatfs() functions return information about a mounted
file system. The returned information is in the format of the statfs
structure that is declared in the </sys/mount.h> file.
When run against an AdvFS clone fileset, the number returned in
statfs.f_bfree is the number of blocks available in the original file‐
set at the time the clone fileset was created. Similarly,
statfs.f_ffree reports the number of potential new files in the origi‐
nal fileset at the time the clone fileset was created.
The ustat() function also returns information about a mounted file sys‐
tem. The returned information is in the format of the ustat structure
that is declared in the <ustat.h> file. This function is superseded by
the statfs() and fstatfs() functions.
Earlier versions of the statfs() and fstatfs() functions documented a
third parameter, length. This length parameter was never used by the
kernel and has been deleted from the documentation.
Upon successful completion, 0 (zero) is returned. Otherwise, -1 is
returned, and errno is set to indicate the error.
If the statfs() function fails, errno may be set to one of the follow‐
ing values: Search permission is denied for a component of the path
prefix of the path parameter. The buffer or path parameter points to a
location outside of the allocated address space of the process. An I/O
error occurred while reading from or writing to the file system. Too
many symbolic links were encountered in translating the path parameter.
The length of a component of the path parameter exceeds NAME_MAX char‐
acters, or the length of the path parameter exceeds PATH_MAX charac‐
ters. The file referred to by the path parameter does not exist. A
component of the path prefix of the path parameter is not a directory.
Indicates a stale NFS file handle. An opened file was deleted by the
server or another client; a client cannot open a file because the
server has unmounted or unexported the remote directory; or the direc‐
tory that contains an opened file was either unmounted or unexported by
If the fstatfs() or ustat() function fails, errno may be set to one of
the following values: The file_descriptor parameter is not a valid file
descriptor. The buffer parameter points to an invalid address. An I/O
error occurred while reading from the file system.
Functions: stat(2), statvfs(2)statfs(2)