man2/sysfs.2

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  23 .\" Created   Wed Aug  9 1995     Thomas K. Dyas <tdyas@eden.rutgers.edu>
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  25 .\" FIXME -- I can't find this in SVr4!
  26 .TH SYSFS 2 1995-08-09 "Linux 1.3.16" "Linux Programmer's Manual"
  27 .SH NAME
  28 sysfs \- get file system type information
  29 .SH SYNOPSIS
  30 .BI "int sysfs(int " option ", const char *" fsname );
  31
  32 .BI "int sysfs(int " option ", unsigned int " fs_index ", char *" buf );
  33
  34 .BI "int sysfs(int " option );
  35 .SH DESCRIPTION
  36 .BR sysfs ()
  37 returns information about the file system types currently present in
  38 the kernel. The specific form of the
  39 .BR sysfs ()
  40 call and the information returned depends on the
  41 .I option
  42 in effect:
  43
  44 .TP
  45 .B 1
  46 Translate the file-system identifier string
  47 .I fsname
  48 into a file-system type index.
  49 .TP
  50 .B 2
  51 Translate the file-system type index
  52 .I fs_index
  53 into a NUL-terminated file-system identifier string. This string will
  54 be written to the buffer pointed to by
  55 .IR buf .
  56 Make sure that
  57 .I buf
  58 has enough space to accept the string.
  59 .TP
  60 .B 3
  61 Return the total number of file system types currently present in the
  62 kernel.
  63
  64 .PP
  65 The numbering of the file-system type indexes begins with zero.
  66 .SH "RETURN VALUE"
  67 On success,
  68 .BR sysfs ()
  69 returns the file-system index for option
  70 .BR 1 ,
  71 zero for option
  72 .BR 2 ,
  73 and the number of currently configured file systems for option
  74 .BR 3 .
  75 On error, \-1 is returned, and
  76 .I errno
  77 is set appropriately.
  78 .SH ERRORS
  79 .TP
  80 .B EFAULT
  81 .RI "Either " fsname " or " buf
  82 is outside your accessible address space.
  83 .TP
  84 .B EINVAL
  85 .I fsname
  86 is not a valid file-system type identifier;
  87 .I fs_index
  88 is out-of-bounds;
  89 .I option
  90 is invalid.
  91 .PP
  92 .SH "CONFORMING TO"
  93 SVr4.
  94 .SH NOTE
  95 On Linux with the
  96 .I proc
  97 filesystem mounted on
  98 .IR /proc ,
  99 the same information can be derived from
 100 .IR /proc/filesystems .
 101 .SH BUGS
 102 There is no libc or glibc support.
 103 There is no way to guess how large \fIbuf\fP should be.