SYSFS(2) Linux Programmer's Manual SYSFS(2)
sysfs - get filesystem type information
int sysfs(int option, const char *fsname);
int sysfs(int option, unsigned int fs_index, char *buf);
int sysfs(int option);
Note: if you are looking for information about the sysfs filesystem
that is normally mounted at /sys, see sysfs(5).
The (obsolete) sysfs() system call returns information about the
filesystem types currently present in the kernel. The specific form of
the sysfs() call and the information returned depends on the option in
1 Translate the filesystem identifier string fsname into a filesystem
2 Translate the filesystem type index fs_index into a null-terminated
filesystem identifier string. This string will be written to the
buffer pointed to by buf. Make sure that buf has enough space to
accept the string.
3 Return the total number of filesystem types currently present in the
The numbering of the filesystem type indexes begins with zero.
On success, sysfs() returns the filesystem index for option 1, zero for
option 2, and the number of currently configured filesystems for option
3. On error, -1 is returned, and errno is set appropriately.
EFAULT Either fsname or buf is outside your accessible address space.
EINVAL fsname is not a valid filesystem type identifier; fs_index is
out-of-bounds; option is invalid.
This System-V derived system call is obsolete; don't use it. On sys-
tems with /proc, the same information can be obtained via
/proc/filesystems; use that interface instead.
There is no libc or glibc support. There is no way to guess how large
buf should be.
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Linux 2017-09-15 SYSFS(2)
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