diff --git a/man3/atexit.3 b/man3/atexit.3
index bccba30d1..4a9a2e5d2 100644
--- a/man3/atexit.3
+++ b/man3/atexit.3
@@ -85,6 +85,23 @@ and the other process termination steps performed by
 .BR exit (3)
 are not performed.
 
+POSIX.1-2001 says that the result of calling
+.BR exit (3)
+more than once (i.e., calling
+.BR exit (3)
+within a function registered using
+.BR atexit (3))
+is undefined.
+On some systems (but not Linux), this can result in an infinite recursion;
+.\" This can happen on OpenBSD 4.2 for example, and is documented
+.\" as occurring on FreeBSD as well.
+.\" Glibc does "the Right Thing" -- invocation of the remaining
+.\" exit handlers carries on as normal.
+portable programs should not invoke
+.BR exit (3)
+inside a function registered using
+.BR atexit (3).
+
 The
 .BR atexit ()
 and