symlink.2: Glibc falls back to symlink() on kernels that lack symlinkat()

man2/symlink.2

@@ -244,6 +244,19 @@ Deleting the name referred to by a symbolic link will actually delete the
 file (unless it also has other hard links).
 If this behavior is not desired, use
 .BR link (2).
+.SS Glibc notes
+On older kernels where
+.BR symlinkat ()
+is unavailable, the glibc wrapper function falls back to the use of
+.BR symlink (2).
+When
+.I linkpath
+is a relative pathname,
+glibc constructs a pathname based on the symbolic link in
+.IR /proc/self/fd
+that corresponds to the
+.IR newdirfd
+argument.
 .SH SEE ALSO
 .BR ln (1),
 .BR lchown (2),