diff --git a/man3/errno.3 b/man3/errno.3
index dacdb0ab0..504c22af5 100644
--- a/man3/errno.3
+++ b/man3/errno.3
@@ -359,6 +359,8 @@ Commonly caused by exceeding the
 .BR RLIMIT_NOFILE
 resource limit described in
 .BR getrlimit (2).
+Can also be caused by exceeding the limit specified in
+.IR /proc/sys/fs/nr_open .
 .TP
 .B EMLINK
 Too many links (POSIX.1-2001).