diff --git a/lib/libm/Makefile b/lib/libm/Makefile
index 46a65b2ae505..32b49950e22f 100644
--- a/lib/libm/Makefile
+++ b/lib/libm/Makefile
@@ -1,4 +1,4 @@
-#  $NetBSD: Makefile,v 1.47 1999/08/15 22:23:53 kleink Exp $
+#  $NetBSD: Makefile,v 1.48 1999/08/16 12:35:18 kleink Exp $
 #
 #  @(#)Makefile 5.1beta 93/09/24
 #
@@ -174,7 +174,9 @@ MLINKS+=ieee_test.3 scalb.3 ieee_test.3 scalbf.3
 MLINKS+=ieee_test.3 significand.3 ieee_test.3 significandf.3
 MLINKS+=j0.3 j0f.3 j0.3 j1.3 j0.3 j1f.3 j0.3 jn.3 j0.3 jnf.3 \
 	j0.3 y0.3 j0.3 y0f.3 j0.3 y1.3 j0.3 y1f.3 j0.3 yn.3 j0.3 ynf.3
-MLINKS+=lgamma.3 lgammaf.3 lgamma.3 gamma.3 lgamma.3 gammaf.3
+MLINKS+=lgamma.3 lgammaf.3 lgamma.3 lgamma_r.3 lgamma.3 lgammaf_r.3 \
+	lgamma.3 gamma.3 lgamma.3 gammaf.3 lgamma.3 gamma_r.3 \
+	lgamma.3 gammaf_r.3
 MLINKS+=rint.3 rintf.3
 MLINKS+=sin.3 sinf.3
 MLINKS+=sinf.3 sinhf.3
diff --git a/lib/libm/man/lgamma.3 b/lib/libm/man/lgamma.3
index 1301f286acdd..8d19f2ed77bc 100644
--- a/lib/libm/man/lgamma.3
+++ b/lib/libm/man/lgamma.3
@@ -30,7 +30,7 @@
 .\" SUCH DAMAGE.
 .\"
 .\"     from: @(#)lgamma.3	6.6 (Berkeley) 12/3/92
-.\"	$NetBSD: lgamma.3,v 1.16 1999/08/15 22:23:54 kleink Exp $
+.\"	$NetBSD: lgamma.3,v 1.17 1999/08/16 12:35:18 kleink Exp $
 .\"
 .Dd December 3, 1992
 .Dt LGAMMA 3
@@ -38,8 +38,12 @@
 .Sh NAME
 .Nm lgamma ,
 .Nm lgammaf ,
+.Nm lgamma_r ,
+.Nm lgammaf_r ,
 .Nm gamma ,
-.Nm gammaf
+.Nm gammaf ,
+.Nm gamma_r ,
+.Nm gammaf_r
 .Nd log gamma function
 .Sh LIBRARY
 .Lb libm
@@ -53,9 +57,17 @@
 .Ft float
 .Fn lgammaf "float x"
 .Ft double
+.Fn lgamma_r "double x" "int *sign"
+.Ft float
+.Fn lgammaf_r "float x" "int *sign"
+.Ft double
 .Fn gamma "double x"
 .Ft float
 .Fn gammaf "float x"
+.Ft double
+.Fn gamma_r "double x" "int *sign"
+.Ft float
+.Fn gammaf_r "float x" "int *sign"
 .Sh DESCRIPTION
 .Fn lgamma x
 .if t \{\
@@ -73,6 +85,15 @@ The external integer
 .Fa signgam
 returns the sign of \(*G(x).
 .Pp
+.Fn lgamma_r
+is a reentrant interface that performs identically to
+.Fn lgamma ,
+differing in that the sign of \(*G(x) is stored in the location
+pointed to by the
+.Fa sign
+argument and
+.Fa signgam
+is not modified.
 .Sh IDIOSYNCRASIES
 Do not use the expression
 .Dq Li signgam\(**exp(lgamma(x))