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GETFSSTAT(2)                BSD System Calls Manual               GETFSSTAT(2)

NAME
     getfsstat -- get list of all mounted file systems

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

     int
     getfsstat(struct statfs *buf, int bufsize, int flags);

DESCRIPTION
     Getfsstat() returns information about all mounted file systems.  Buf is a pointer to an array of statfs
     structures defined as follows:

     typedef struct { int32_t val[2]; } fsid_t;

     #define MFSNAMELEN   15 /* length of fs type name, not inc. nul */
     #define MNAMELEN     90 /* length of buffer for returned name */

     struct statfs {
         short   f_otype;    /* type of file system (reserved: zero) */
         short   f_oflags;   /* copy of mount flags (reserved: zero) */
         long    f_bsize;    /* fundamental file system block size */
         long    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 */
         long    f_files;    /* total file nodes in file system */
         long    f_ffree;    /* free file nodes in fs */
         fsid_t  f_fsid;     /* file system id (super-user only) */
         uid_t   f_owner;    /* user that mounted the file system */
         short   f_reserved1;        /* reserved for future use */
         short   f_type;     /* type of file system (reserved) */
         long    f_flags;    /* copy of mount flags (reserved) */
         long    f_reserved2[2];     /* reserved for future use */
         char    f_fstypename[MFSNAMELEN]; /* fs type name */
         char    f_mntonname[MNAMELEN];    /* directory on which mounted */
         char    f_mntfromname[MNAMELEN];  /* mounted file system */
         char    f_reserved3;        /* reserved for future use */
         long    f_reserved4[4];     /* reserved for future use */
     };

     Fields that are undefined for a particular file system are set to -1.  The buffer is filled with an
     array of statfs structures, one for each mounted file system up to the size specified by bufsize.

     If buf is given as NULL, getfsstat() returns just the number of mounted file systems.

     If flags is set to MNT_NOWAIT, getfsstat() will directly return the information retained in the kernel
     to avoid delays caused by waiting for updated information from a file system that is perhaps temporar-ily temporarily
     ily unable to respond.  Some of the information returned may be out of date, however; if flags is set
     to MNT_WAIT instead, getfsstat() will request updated information from each mounted filesystem before
     returning.

RETURN VALUES
     Upon successful completion, the number of statfs structures is returned.  Otherwise, -1 is returned and
     the global variable errno is set to indicate the error.

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

     [EFAULT]           Buf points to an invalid address.

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

SEE ALSO
     statfs(2), fstab(5), mount(8)

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

BSD                              June 9, 1993                              BSD