#include <sys/statvfs.h> int statvfs(const char *restrict path, struct statvfs *restrict buf); int fstatvfs(int fd, struct statvfs *buf);
struct statvfs {
unsigned long f_bsize; /* Filesystem block size */
unsigned long f_frsize; /* Fragment size */
fsblkcnt_t f_blocks; /* Size of fs in f_frsize units */
fsblkcnt_t f_bfree; /* Number of free blocks */
fsblkcnt_t f_bavail; /* Number of free blocks for
unprivileged users */
fsfilcnt_t f_files; /* Number of inodes */
fsfilcnt_t f_ffree; /* Number of free inodes */
fsfilcnt_t f_favail; /* Number of free inodes for
unprivileged users */
unsigned long f_fsid; /* Filesystem ID */
unsigned long f_flag; /* Mount flags */
unsigned long f_namemax; /* Maximum filename length */
};
Here the types fsblkcnt_t and fsfilcnt_t are defined in <sys/types.h>. Both used to be unsigned long.
The field f_flag is a bit mask indicating various options that were employed when mounting this filesystem. It contains zero or more of the following flags:
It is unspecified whether all members of the returned struct have meaningful values on all filesystems.
fstatvfs() returns the same information about an open file referenced by descriptor fd.
Interface | Attribute | Value |
statvfs(), fstatvfs() | Thread safety | MT-Safe |
Only the ST_NOSUID and ST_RDONLY flags of the f_flag field are specified in POSIX.1. To obtain definitions of the remaining flags, one must define _GNU_SOURCE.
Before glibc 2.13, statvfs() populated the bits of the f_flag field by scanning the mount options shown in /proc/mounts. However, starting with Linux 2.6.36, the underlying statfs(2) system call provides the necessary information via the f_flags field, and since glibc 2.13, the statvfs() function will use information from that field rather than scanning /proc/mounts.
The glibc implementations of
pathconf(path, _PC_REC_XFER_ALIGN); pathconf(path, _PC_ALLOC_SIZE_MIN); pathconf(path, _PC_REC_MIN_XFER_SIZE);
respectively use the f_frsize, f_frsize, and f_bsize fields returned by a call to statvfs() with the argument path.