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.\" Created   Wed Aug  9 1995     Thomas K. Dyas <tdyas@eden.rutgers.edu>

.\"

.TH SYSFS 2 2017-09-15 "Linux" "Linux Programmer's Manual"

.SH NAME

sysfs \- get filesystem type information

.SH SYNOPSIS

.BI "int sysfs(int " option ", const char *" fsname );

.PP

.BI "int sysfs(int " option ", unsigned int " fs_index ", char *" buf );

.PP

.BI "int sysfs(int " option );

.SH DESCRIPTION

.BR "Note" :

if you are looking for information about the

.B sysfs

filesystem that is normally mounted at

.IR /sys ,

see

.BR sysfs (5).

.PP

The (obsolete)

.BR sysfs ()

system call returns information about the filesystem types

currently present in the kernel.

The specific form of the

.BR sysfs ()

call and the information returned depends on the

.I option

in effect:

.TP 3

.B 1

Translate the filesystem identifier string

.I fsname

into a filesystem type index.

.TP

.B 2

Translate the filesystem type index

.I fs_index

into a null-terminated filesystem identifier string.

This string will

be written to the buffer pointed to by

.IR buf .

Make sure that

.I buf

has enough space to accept the string.

.TP

.B 3

Return the total number of filesystem types currently present in the

kernel.

.PP

The numbering of the filesystem type indexes begins with zero.

.SH RETURN VALUE

On success,

.BR sysfs ()

returns the filesystem index for option

.BR 1 ,

zero for option

.BR 2 ,

and the number of currently configured filesystems for option

.BR 3 .

On error, \-1 is returned, and

.I errno

is set appropriately.

.SH ERRORS

.TP

.B EFAULT

.RI "Either " fsname " or " buf

is outside your accessible address space.

.TP

.B EINVAL

.I fsname

is not a valid filesystem type identifier;

.I fs_index

is out-of-bounds;

.I option

is invalid.

.SH CONFORMING TO

SVr4.

.SH NOTES

This System-V derived system call is obsolete; don't use it.

On systems with

.IR /proc ,

the same information can be obtained via

.IR /proc/filesystems ;

use that interface instead.

.SH BUGS

There is no libc or glibc support.

There is no way to guess how large \fIbuf\fP should be.

.SH COLOPHON

This page is part of release 4.15 of the Linux

.I man-pages

project.

A description of the project,

information about reporting bugs,

and the latest version of this page,

can be found at

\%https://www.kernel.org/doc/man\-pages/.