diff --git a/man2/utimensat.2 b/man2/utimensat.2
index f944b0814..d06d42db2 100644
--- a/man2/utimensat.2
+++ b/man2/utimensat.2
@@ -458,7 +458,7 @@ succeeds even if the file referred to by
 and
 .I pathname
 does not exist.
-
+.SS C library/ kernel ABI differences
 On Linux,
 .BR futimens ()
 is a library function implemented on top of the
@@ -479,6 +479,14 @@ is implemented as:
 
     utimensat(fd, NULL, times, 0);
 .fi
+
+Note, however, that the glibc wrapper for
+.BR utimensat ()
+disallows passing NULL as the value for
+.IR file :
+the wrapper function returns the error
+.IR EINVAL
+in this case.
 .SH BUGS
 Several bugs afflict
 .BR utimensat ()