GETFSSTAT(2)              FreeBSD System Calls Manual             GETFSSTAT(2)

NAME
     getfsstat - get list of all mounted file systems

LIBRARY
     Standard C Library (libc, -lc)

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

     int
     getfsstat(struct statfs *buf, long bufsize, int mode);

DESCRIPTION
     The getfsstat() system call returns information about all mounted file
     systems.  The buf argument is a pointer to statfs structures, as
     described in statfs(2).

     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 byte count specified by bufsize.  Note, the
     bufsize argument is the number of bytes that buf can hold, not the count
     of statfs structures it will hold.

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

     Normally mode should be specified as MNT_WAIT.  If mode is set to
     MNT_NOWAIT, getfsstat() will return the information it has available
     without requesting an update from each file system.  Thus, some of the
     information will be out of date, but getfsstat() will not block waiting
     for information from a file system that is unable to respond.  It will
     also skip any file system that is in the process of being unmounted, even
     if the unmount would eventually fail.

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
     The getfsstat() system call fails if one or more of the following are
     true:

     [EFAULT]           The buf argument points to an invalid address.

     [EINVAL]           mode is set to a value other than MNT_WAIT or
                        MNT_NOWAIT.

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

     [EINTEGRITY]       Corrupted data was detected while reading from the
                        file system.

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

HISTORY
     The getfsstat() system call first appeared in 4.4BSD.

FreeBSD 13.1-RELEASE-p6         March 30, 2020         FreeBSD 13.1-RELEASE-p6