returns information about all mounted file systems.
is a pointer to
structures, as described in
Fields that are undefined for a particular file system are set to -1.
The buffer is filled with an array of
structures, one for each mounted file system
up to the byte count specified by
argument is the number of bytes that
can hold, not the count of statfs structures it will hold.
is given as NULL,
returns just the number of mounted file systems.
should be specified as
is set to
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Thus, some of the information will be out of date, but
will not block waiting for information from a file system that is
unable to respond.