STATFS(2)

NAME
statfs, fstatfs - get file system statistics

SYNOPSIS
#include <sys/types.h>
#include <sys/mount.h>
int
statfs(const char *path, struct statfs *buf);
int
fstatfs(int fd, struct statfs *buf);

DESCRIPTION
statfs() returns information about a mounted file system. path is the pathname of any file within the mounted file system. buf is a pointer to a statfs structure defined as follows:

    typedef struct { int32_t val[2]; } fsid_t;
    #define MFSNAMELEN   16 /* length of fs type name, including nul */
    #define MNAMELEN     90	/* length of buffer for returned name */
    struct statfs {
        u_int32_t	f_flags;	/* copy of mount flags */
        u_int32_t	f_bsize;	/* file system block size */
        u_int32_t	f_iosize;	/* optimal transfer block size */
    				/* unit is f_bsize */
        u_int64_t	f_blocks;	/* total data blocks in file system */
        u_int64_t	f_bfree;	/* free blocks in fs */
        int64_t	f_bavail;	/* free blocks avail to non-superuser */
        u_int64_t	f_files;	/* total file nodes in file system */
        u_int64_t	f_ffree;	/* free file nodes in fs */
        int64_t	f_favail;	/* free file nodes avail to non-root */
        u_int64_t	f_syncwrites;	/* count of sync writes since mount */
        u_int64_t	f_syncreads;	/* count of sync reads since mount */
        u_int64_t	f_asyncwrites;	/* count of async writes since mount */
        u_int64_t	f_asyncreads;	/* count of async reads since mount */
        fsid_t	f_fsid;		/* file system id */
        u_int32_t	f_namemax;	/* maximum filename length */
        uid_t	f_owner;	/* user that mounted the file system */
        u_int64_t	f_ctime;	/* last mount [-u] time */
        char f_fstypename[MFSNAMELEN]; /* fs type name */
        char f_mntonname[MNAMELEN];    /* directory on which mounted */
        char f_mntfromname[MNAMELEN];  /* mounted file system */
        char f_mntfromspec[MNAMELEN];  /* special for mount request */
        union mount_info mount_info;   /* per-filesystem mount options */
    };

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

Note that f_fsid will be empty unless the user is the superuser.

RETURN VALUES

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.

[ENAMETOOLONG]
    A component of a pathname exceeded NAME_MAX characters, or an entire pathname (including the terminating NUL) exceeded PATH_MAX bytes.

[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.

SEE ALSO
df(1), getfsstat(2), mount(2), stat(2)

HISTORY
The statfs() function first appeared in 4.4BSD.