---
name: "ustat"
section: "2"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/ustat/2"
---

# ustat(2)

get filesystem statistics

## NAME

ustat - get filesystem statistics

## LIBRARY

Standard C library (*libc*, *-lc*)

## SYNOPSIS

```
#include <sys/types.h>
#include <unistd.h>    /* libc[45] */
#include <ustat.h>     /* glibc2 */
```

**\[\[deprecated\]\] int ustat(dev\_t** *dev***, struct ustat \****ubuf***);**

## DESCRIPTION

**ustat**() returns information about a mounted filesystem. *dev* is a device number identifying a device containing a mounted filesystem. *ubuf* is a pointer to a *ustat* structure that contains the following members:

```
daddr_t f_tfree;      /* Total free blocks */
ino_t   f_tinode;     /* Number of free inodes */
char    f_fname[6];   /* Filsys name */
char    f_fpack[6];   /* Filsys pack name */
```

The last two fields, *f\_fname* and *f\_fpack*, are not implemented and will always be filled with null bytes ('\\0').

## RETURN VALUE

On success, zero is returned and the *ustat* structure pointed to by *ubuf* will be filled in. On error, -1 is returned, and *errno* is set to indicate the error.

## ERRORS

- **EFAULT**

  *ubuf* points outside of your accessible address space.

- **EINVAL**

  *dev* does not refer to a device containing a mounted filesystem.

- **ENOSYS**

  The mounted filesystem referenced by *dev* does not support this operation, or any version of Linux before Linux 1.3.16.

## STANDARDS

None.

## HISTORY

SVr4. Removed in glibc 2.28.

**ustat**() is deprecated and has been provided only for compatibility. All new programs should use [**statfs**(2)](/statfs/2.md) instead.

### HP-UX notes

The HP-UX version of the *ustat* structure has an additional field, *f\_blksize*, that is unknown elsewhere. HP-UX warns: For some filesystems, the number of free inodes does not change. Such filesystems will return -1 in the field *f\_tinode*. For some filesystems, inodes are dynamically allocated. Such filesystems will return the current number of free inodes.

## SEE ALSO

[**stat**(2)](/stat/2.md), [**statfs**(2)](/statfs/2.md)