man2/ustat.2

   1 .\" Copyright (C) 1995, Thomas K. Dyas <tdyas@eden.rutgers.edu>
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  24 .\"
  25 .\" Created  1995-08-09 Thomas K. Dyas <tdyas@eden.rutgers.edu>
  26 .\" Modified 1997-01-31 by Eric S. Raymond <esr@thyrsus.com>
  27 .\" Modified 2001-03-22 by aeb
  28 .\" Modified 2003-08-04 by aeb
  29 .\"
  30 .TH USTAT 2 2017-09-15 "Linux" "Linux Programmer's Manual"
  31 .SH NAME
  32 ustat \- get filesystem statistics
  33 .SH SYNOPSIS
  34 .nf
  35 .B #include <sys/types.h>
  36 .BR "#include <unistd.h>" "    /* libc[45] */"
  37 .BR "#include <ustat.h>" "     /* glibc2 */"
  38 .PP
  39 .BI "int ustat(dev_t " dev ", struct ustat *" ubuf );
  40 .fi
  41 .SH DESCRIPTION
  42 .BR ustat ()
  43 returns information about a mounted filesystem.
  44 .I dev
  45 is a device number identifying a device containing
  46 a mounted filesystem.
  47 .I ubuf
  48 is a pointer to a
  49 .I ustat
  50 structure that contains the following
  51 members:
  52 .PP
  53 .in +4n
  54 .EX
  55 daddr_t f_tfree;      /* Total free blocks */
  56 ino_t   f_tinode;     /* Number of free inodes */
  57 char    f_fname[6];   /* Filsys name */
  58 char    f_fpack[6];   /* Filsys pack name */
  59 .EE
  60 .in
  61 .PP
  62 The last two fields,
  63 .I f_fname
  64 and
  65 .IR f_fpack ,
  66 are not implemented and will
  67 always be filled with null bytes (\(aq\\0\(aq).
  68 .SH RETURN VALUE
  69 On success, zero is returned and the
  70 .I ustat
  71 structure pointed to by
  72 .I ubuf
  73 will be filled in.
  74 On error, \-1 is returned, and
  75 .I errno
  76 is set appropriately.
  77 .SH ERRORS
  78 .TP
  79 .B EFAULT
  80 .I ubuf
  81 points outside of your accessible address space.
  82 .TP
  83 .B EINVAL
  84 .I dev
  85 does not refer to a device containing a mounted filesystem.
  86 .TP
  87 .B ENOSYS
  88 The mounted filesystem referenced by
  89 .I dev
  90 does not support this operation, or any version of Linux before
  91 1.3.16.
  92 .SH CONFORMING TO
  93 SVr4.
  94 .\" SVr4 documents additional error conditions ENOLINK, ECOMM, and EINTR
  95 .\" but has no ENOSYS condition.
  96 .SH NOTES
  97 .BR ustat ()
  98 is deprecated and has been provided only for compatibility.
  99 All new programs should use
 100 .BR statfs (2)
 101 instead.
 102 .SS HP-UX notes
 103 The HP-UX version of the
 104 .I ustat
 105 structure has an additional field,
 106 .IR f_blksize ,
 107 that is unknown elsewhere.
 108 HP-UX warns:
 109 For some filesystems, the number of free inodes does not change.
 110 Such filesystems will return \-1 in the field
 111 .IR f_tinode .
 112 .\" Some software tries to use this in order to test whether the
 113 .\" underlying filesystem is NFS.
 114 For some filesystems, inodes are dynamically allocated.
 115 Such filesystems will return the current number of free inodes.
 116 .SH SEE ALSO
 117 .BR stat (2),
 118 .BR statfs (2)