The sysfs() function returns information about the file system types configured in the system. The number of arguments accepted by sysfs() depends on the opcode argument, which can take the following values:
GETFSIND
Translate fsname, a null-terminated file-system type identifier,
into a file-system type index.
GETFSTYP
Translate fs_index, a file-system type index, into a null-terminated file-system type identifier and write it
into the buffer pointed to by buf, which must be at least of size FSTYPSZ as defined in <sys/fstyp.h>.
GETNFSTYP
Return the total number of file system types configured in the system.
RETURN VALUES
Upon successful completion, the value returned depends upon the opcode argument as follows:
GETFSIND
the file-system type index
GETFSTYP
0
GETNFSTYP
the number of file system types configured
Otherwise, -1 is returned and errno is set to indicate the error.
ERRORS
The sysfs() function will fail if:
EFAULT
The buf or fsname argument points to an
illegal address.
EINVAL
The fsname argument points to an invalid file-system identifier; the fs_index argument
is 0 or invalid; or the opcode argument is invalid.