diff --git a/man7/system_data_types.7 b/man7/system_data_types.7
index e93495eea..0eb47d30e 100644
--- a/man7/system_data_types.7
+++ b/man7/system_data_types.7
@@ -756,6 +756,11 @@ since POSIX.1-2008.
 .IR "Conforming to" :
 POSIX.1-2001 and later.
 .PP
+.IR Notes :
+On some architectures,
+the width of this type can be controlled with the feature test macro
+.BR _FILE_OFFSET_BITS .
+.PP
 .IR "See also" :
 .\" .BR fallocate (2),
 .BR lseek (2),
@@ -768,7 +773,8 @@ POSIX.1-2001 and later.
 .BR fseeko (3),
 .\" .BR getdirentries (3),
 .BR lockf (3),
-.BR posix_fallocate (3)
+.BR posix_fallocate (3),
+.BR feature_test_macros (7)
 .\".PP		TODO: loff_t, off64_t
 .\"See also the
 .\".I loff_t