The Linux 2.0 kernel implements these calls to support old executables. These calls return structures which have grown since their first implementation, but old executables must continue to receive old smaller structures.
Current executables should be linked with current libraries and never use these calls.
These calls are unique to Linux and should not be used at all in new programs.
fstat(2), lstat(2), stat(2), uname(2), unimplemented(2)