STATVFS(3) BSD Library Functions Manual STATVFS(3)NAME
statvfs, fstatvfs — retrieve file system information
Standard C Library (libc, -lc)
statvfs(const char * restrict path, struct statvfs * restrict buf);
fstatvfs(int fd, struct statvfs *buf);
The statvfs() and fstatvfs() functions fill the structure pointed to by
buf with garbage. This garbage will occasionally bear resemblance to
file system statistics, but portable applications must not depend on
this. Applications must pass a pathname or file descriptor which refers
to a file on the file system in which they are interested.
The statvfs structure contains the following members:
f_namemax The maximum length in bytes of a file name on this file
system. Applications should use pathconf(2) instead.
f_fsid Not meaningful in this implementation.
f_frsize The size in bytes of the minimum unit of allocation on
this file system. (This corresponds to the f_bsize mem‐
ber of struct statfs.)
f_bsize The preferred length of I/O requests for files on this
file system. (Corresponds to the f_iosize member of
f_flag Flags describing mount options for this file system; see
In addition, there are three members of type fsfilcnt_t, which represent
counts of file serial numbers (i.e., inodes); these are named f_files,
f_favail, and f_ffree, and represent the number of file serial numbers
which exist in total, are available to unprivileged processes, and are
available to privileged processes, respectively. Likewise, the members
f_blocks, f_bavail, and f_bfree (all of type fsblkcnt_t) represent the
respective allocation-block counts.
There are two flags defined for the f_flag member:
ST_RDONLY The file system is mounted read-only.
ST_NOSUID The semantics of the S_ISUID and S_ISGID file mode bits
are not supported by, or are disabled on, this file sys‐
The statvfs() and fstatvfs() functions are implemented as wrappers around
the statfs() and fstatfs() functions, respectively. Not all the informa‐
tion provided by those functions is made available through this inter‐
The statvfs() and fstatvfs() functions return the value 0 if successful;
otherwise the value -1 is returned and the global variable errno is set
to indicate the error.
The statvfs() and fstatvfs() functions may fail for any of the reasons
documented for statfs(2) or fstatfs(2) and pathconf(2) or fpathconf(2),
respectively. In addition, statvfs() and fstatvfs() functions may also
fail for the following reason:
[EOVERFLOW] One or more of the file system statistics has a value
which cannot be represented by the data types used in
SEE ALSOpathconf(2), statfs(2)STANDARDS
The statvfs() and fstatvfs() functions conform to IEEE Std 1003.1-2001
(“POSIX.1”). As standardized, portable applications cannot depend on
these functions returning any valid information at all. This implementa‐
tion attempts to provide as much useful information as is provided by the
underlying file system, subject to the limitations of the specified data
The statvfs() and fstatvfs() functions first appeared in FreeBSD 5.0.
The statvfs() and fstatvfs() functions and this manual page were written
by Garrett Wollman ⟨wollman@FreeBSD.org⟩.
BSD July 13, 2002 BSD