redhat man page for sysfs

SYSFS(2)						     Linux Programmer's Manual							  SYSFS(2)

NAME
       sysfs - get file system type information

SYNOPSIS
       int sysfs(int option, const char *fsname);

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

       int sysfs(int option);

DESCRIPTION
       sysfs returns information about the file system types currently present in the kernel. The specific form of the sysfs call and the informa-
       tion returned depends on the option in effect:

       1      Translate the file-system identifier string fsname into a file-system type index.

       2      Translate the file-system type index fs_index into a null-terminated file-system 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 file system types currently present in the kernel.

       The numbering of the file-system type indexes begins with zero.

RETURN VALUE
       On  success,  sysfs  returns the file-system index for option 1, zero for option 2, and the number of currently configured file systems for
       option 3.  On error, -1 is returned, and errno is set appropriately.

ERRORS
       EINVAL fsname is not a valid file-system type identifier; fs_index is out-of-bounds; option is invalid.

       EFAULT Either fsname or buf is outside your accessible address space.

CONFORMING TO
       SVr4.

NOTE
       On Linux with the proc filesystem mounted on /proc, the same information can be derived from /proc/filesystems.

BUGS
       There is no libc or glibc support.  There is no way to guess how large buf should be.

Linux 1.3.16							    1995-08-09								  SYSFS(2)