statvfs(), statvfs64()

Get filesystem information, given a path

Synopsis:

#include <sys/statvfs.h>

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

int statvfs64( const char *path,
               struct statvfs64 *buf );

Arguments:

path

The name of a file that resides on the filesystem.

buf

A pointer to a buffer where the function can store the information.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The statvfs() function returns a “generic superblock” describing a filesystem; it can be used to acquire information about mounted filesystems. The statvfs64() function is a 64-bit version of statvfs().

The filesystem type is known to the operating system. You don't need to have read, write, or execute permission for the named file, but all directories listed in the path name leading to the file must be searchable.

The buf argument is a pointer to a statvfs or statvfs64 structure that's filled by the function. It contains at least:

unsigned long f_bsize

The preferred filesystem blocksize.

unsigned long f_frsize

The fundamental filesystem blocksize (if supported)

fsblkcnt_t f_blocks

The total number of blocks on the filesystem, in units of f_frsize.

fsblkcnt_t f_bfree

The total number of free blocks.

fsblkcnt_t f_bavail

The number of free blocks available to a nonsuperuser.

fsfilcnt_t f_files

The total number of file nodes (inodes).

fsfilcnt_t f_ffree

The total number of free file nodes.

fsfilcnt_t f_favail

The number of inodes available to a nonsuperuser.

unsigned long f_fsid

The filesystem ID (dev for now).

char f_basetype[16]

The type of the target filesystem, as a null-terminated string.

unsigned long f_flag

A bitmask of flags; the function can set these flags:

• ST_RDONLY — read-only filesystem.
• ST_NOSUID — the filesystem doesn't support setuid/setgid semantics.

unsigned long f_namemax

The maximum filename length.

Returns:

0

Success.

-1

An error occurred (errno is set).

Errors:

EACCES

Search permission is denied on a component of the path prefix.

EFAULT

The path or buf argument points to an illegal address.

EINTR

A signal was caught during execution.

EIO

An I/O error occurred while reading the filesystem.

ELOOP

Too many symbolic links were encountered in translating path.

EMULTIHOP

Components of path require hopping to multiple remote machines and the filesystem type doesn't allow it.

ENAMETOOLONG

The length of a path component exceeds {NAME_MAX} characters, or the length of path exceeds {PATH_MAX} characters.

ENOENT

Either a component of the path prefix or the file referred to by path doesn't exist.

ENOLINK

The path argument points to a remote machine and the link to that machine is no longer active.

ENOTDIR

A component of the path prefix of path isn't a directory.

EOVERFLOW

One of the values to be returned can't be represented correctly in the structure pointed to by buf.

Classification:

statvfs() is POSIX 1003.1 XSI; statvfs64() is Large-file support

Caveats:

The values returned for f_files, f_ffree, and f_favail might not be valid for NFS-mounted filesystems.

See also:

chmod(), chown(), creat(), dup(), fcntl(), fstatvfs(), fstatvfs64(), link(), mknod(), open(), pipe(), read(), time(), unlink(), utime(), write()