diff --git a/lib/libsys/sendfile.2 b/lib/libsys/sendfile.2
--- a/lib/libsys/sendfile.2
+++ b/lib/libsys/sendfile.2
@@ -23,7 +23,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd June 24, 2025
+.Dd January 21, 2026
 .Dt SENDFILE 2
 .Os
 .Sh NAME
@@ -325,6 +325,7 @@
 If specified, the number
 of bytes successfully sent will be returned in
 .Fa *sbytes .
+This error shall never be returned if the socket is non-blocking.
 .It Bq Er EINVAL
 The
 .Fa fd