ustat.2 (2010 09)

ustat(2) ustat(2)

NAME

ustat() - get mounted ﬁle system statistics

SYNOPSIS

#include <ustat.h>

int ustat(dev_t dev, struct ustat *buf);

DESCRIPTION

The ustat() system call returns information about a mounted ﬁle system. dev is a device number iden-

tifying a device containing a mounted ﬁle system. buf is a pointer to a

ustat structure (deﬁned in

<ustat.h>) that includes the following elements:

int32_t f_tfree; /* Total free blocks */

ino_t f_tinode; /* Number of free inodes */

char f_fname[6]; /* Filsys name or null */

char f_fpack[6]; /* Filsys pack name or null */

int f_blksize; /* Block size */

The value of

f_tfree is the number of free blocks of size

f_blksize.

RETURN VALUE

ustat() returns the following values:

0 Successful completion.

-1 Failure. errno is set to indicate the error.

ERRORS

ustat() fails, errno is set to one of the following values.

[EFAULT] buf points outside the process’s allocated address space. The reliable detection

of this error is implementation dependent.

[EINVAL] dev is not the device number of a device containing a mounted ﬁle system.

[EOVERFLOW] Result would overﬂow f_tfree or another ﬁeld of the

ustat struct.

WARNINGS

ustat() is deprecated and should be used only by legacy 32-bit applications.

statvfs() or

statvfs64() are the recommended replacements.

For some ﬁle systems, the number of free inodes does not change. Such ﬁle systems will return

-1 in the

ﬁeld

f_tinode.

For some ﬁle systems, the inodes can be dynamically allocated. For such ﬁle systems, the ﬁeld

f_tinode contains the number of free inodes at the current time.

AUTHOR

ustat() was developed by AT&T and HP.