STATFS(2)

NAME
statfs, fstatfs - get file system statistics

SYNOPSIS
#include <sys/param.h>
#include <sys/mount.h>

int
statfs(path,buf)
char *path;
struct statfs *buf;

int
fstatfs(fd,buf)
int fd;
struct statfs *buf;

DESCRIPTION
Statfs() returns information about a mounted file system. Path is the path name of any file within the mounted filesystem. Buf is a pointer to a statfs structure defined as follows:

#define MNAMELEN 90       /* length of buffer for returned name */
struct statfs {
short   f_type;           /* type of filesystem (see below) */
short   f_flags;          /* copy of mount flags */
short   f_bsize;          /* fundamental file system block size */
short   f_iosize;         /* optimal transfer block size */
long    f_blocks;         /* total data blocks in file system */
long    f_bfree;          /* free blocks in fs */
long    f_bavail;         /* free blocks avail to non-superuser */
ino_t   f_files;          /* total file nodes in file system */
ino_t   f_ffree;          /* free file nodes in fs */
u_long  f_fsid[2];        /* file system id */
long    f_spare[4];       /* spare for later */
char    f_mntonname[MNAMELEN];    /* mount point */
char    f_mntfromname[MNAMELEN];  /* mounted filesystem */
};
/*
* File system types. - Only UFS is supported so the other types are not
* given.
*/
#define	MOUNT_UFS	1	/* Fast Filesystem */

Fields that are undefined for a particular file system are set to -1. Fstatfs() returns the same information about an open file referenced by descriptor fd.

RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, -1 is returned and the global variable errno is set to indicate the error.

ERRORS
Statfs() fails if one or more of the following are true:

[ENOTDIR]
    A component of the path prefix of Path is not a directory.

[EINVAL]
    path contains a character with the high-order bit set.

[ENAMETOOLONG]
    The length of a component of path exceeds 63 characters, or the length of path exceeds 255 characters.

[ENOENT]
    The file referred to by path does not exist.

[EACCES]
    Search permission is denied for a component of the path prefix of path.

[ELOOP]
    Too many symbolic links were encountered in translating path.

[EFAULT]
    Buf or path points to an invalid address.

[EIO]
    An I/O error occurred while reading from or writing to the file system.

Fstatfs() fails if one or more of the following are true:

[EBADF]
    Fd is not a valid open file descriptor.

[EFAULT]
    Buf points to an invalid address.

[EIO]
    An I/O error occurred while reading from or writing to the file system.

HISTORY
The statfs function first appeared in 4.4BSD.