diff --git a/lib/msun/Makefile b/lib/msun/Makefile
index b6452c6cd579..28f3db251fec 100644
--- a/lib/msun/Makefile
+++ b/lib/msun/Makefile
@@ -129,10 +129,10 @@ MLINKS+=fmax.3 fmaxf.3 fmax.3 fmaxl.3 \
 	fmax.3 fmin.3 fmax.3 fminf.3 fmax.3 fminl.3
 MLINKS+=fmod.3 fmodf.3
 MLINKS+=hypot.3 cabs.3 hypot.3 cabsf.3 hypot.3 hypotf.3
-MLINKS+=ieee_test.3 logb.3 ieee_test.3 logbf.3
 MLINKS+=ieee_test.3 scalb.3 ieee_test.3 scalbf.3
 MLINKS+=ieee_test.3 significand.3 ieee_test.3 significandf.3
-MLINKS+=ilogb.3 ilogbf.3 ilogb.3 ilogbl.3
+MLINKS+=ilogb.3 ilogbf.3 ilogb.3 ilogbl.3 \
+	ilogb.3 logb.3 ilogb.3 logbf.3
 MLINKS+=j0.3 j1.3 j0.3 jn.3 j0.3 y0.3 j0.3 y1.3 j0.3 y1f.3 j0.3 yn.3
 MLINKS+=j0.3 j0f.3 j0.3 j1f.3 j0.3 jnf.3 j0.3 y0f.3 j0.3 ynf.3
 MLINKS+=lgamma.3 gamma.3 lgamma.3 gammaf.3 lgamma.3 lgammaf.3 lgamma.3 tgamma.3
diff --git a/lib/msun/man/ieee_test.3 b/lib/msun/man/ieee_test.3
index 986fd08b9ae8..50ea23c84f97 100644
--- a/lib/msun/man/ieee_test.3
+++ b/lib/msun/man/ieee_test.3
@@ -32,12 +32,10 @@
 .\"     from: @(#)ieee.3	6.4 (Berkeley) 5/6/91
 .\" $FreeBSD$
 .\"
-.Dd March 10, 1994
+.Dd Nov 6, 2005
 .Dt IEEE_TEST 3
 .Os
 .Sh NAME
-.Nm logb ,
-.Nm logbf ,
 .Nm scalb ,
 .Nm scalbf ,
 .Nm significand ,
@@ -48,10 +46,6 @@
 .Sh SYNOPSIS
 .In math.h
 .Ft double
-.Fn logb "double x"
-.Ft float
-.Fn logbf "float x"
-.Ft double
 .Fn scalb "double x" "double n"
 .Ft float
 .Fn scalbf "float x" "float n"
@@ -64,18 +58,6 @@ These functions allow users to test conformance to
 .St -ieee754 .
 Their use is not otherwise recommended.
 .Pp
-.Fn logb x
-and
-.Fn logbf x
-return
-.Fa x Ns 's exponent
-.Fa n ,
-a signed integer converted to double\-precision floating\-point.
-.Fn logb \*(Pm\*(If
-= +\*(If;
-.Fn logb 0
-= -\*(If with a division by zero exception.
-.Pp
 .Fn scalb x n
 and
 .Fn scalbf x n
diff --git a/lib/msun/man/ilogb.3 b/lib/msun/man/ilogb.3
index 401e86df7256..1de5f8c7eb8a 100644
--- a/lib/msun/man/ilogb.3
+++ b/lib/msun/man/ilogb.3
@@ -32,13 +32,15 @@
 .\"     from: @(#)ieee.3	6.4 (Berkeley) 5/6/91
 .\" $FreeBSD$
 .\"
-.Dd January 26, 2005
+.Dd Nov 6, 2005
 .Dt ILOGB 3
 .Os
 .Sh NAME
 .Nm ilogb ,
 .Nm ilogbf ,
-.Nm ilogbl
+.Nm ilogbl ,
+.Nm logb ,
+.Nm logbf
 .Nd extract exponent
 .Sh LIBRARY
 .Lb libm
@@ -50,24 +52,40 @@
 .Fn ilogbf "float x"
 .Ft int
 .Fn ilogbl "long double x"
+.Ft double
+.Fn logb "double x"
+.Ft float
+.Fn logbf "float x"
 .Sh DESCRIPTION
 .Fn ilogb ,
 .Fn ilogbf
 and
 .Fn ilogbl
 return
-.Fa x Ns 's exponent,
+.Fa x Ns 's exponent
 in integer format.
 .Fn ilogb \*(Pm\*(If
 returns
 .Dv INT_MAX ,
 .Fn ilogb \*(Pm\*(Na
 returns
-.Dv FP_ILOGBNAN
+.Dv FP_ILOGBNAN ,
 and
 .Fn ilogb 0
 returns
 .Dv FP_ILOGB0 .
+.Pp
+.Fn logb x
+and
+.Fn logbf x
+return
+.Fa x Ns 's exponent
+in floating\-point format with the same precision as
+.Fa x .
+.Fn logb \*(Pm\*(If
+returns +\*(If, and
+.Fn logb 0
+returns -\*(If with a division by zero exception.
 .Sh SEE ALSO
 .Xr frexp 3 ,
 .Xr ieee 3 ,
@@ -77,19 +95,33 @@ returns
 The
 .Fn ilogb ,
 .Fn ilogbf ,
+.Fn ilogbl ,
+.Fn logb
 and
-.Fn ilogbl
+.Fn logbf
 routines conform to
 .St -isoC-99 .
-They provide functionality similar to the Logb function recommended by
+.Fn logb
+and
+.Fn logbf
+implement the logb function recommended by
 .St -ieee754 .
 .Sh HISTORY
 The
+.Fn logb
+function appeared in
+.Bx 4.3 .
+The
 .Fn ilogb
-and
+function appeared in
+.Fx 1.1.5 .
+The
 .Fn ilogbf
-functions appeared in
-.Bx 4.3
 and
-.Fx 2.0 ,
-respectively.
+.Fn logbf
+functions appeared in
+.Fx 2.0 .
+The
+.Fn ilogbl
+function appeared in
+.Fx 5.4 .
diff --git a/lib/msun/man/math.3 b/lib/msun/man/math.3
index a0d1fdef3589..db3a6661ac9c 100644
--- a/lib/msun/man/math.3
+++ b/lib/msun/man/math.3
@@ -32,7 +32,7 @@
 .\"	from: @(#)math.3	6.10 (Berkeley) 5/6/91
 .\" $FreeBSD$
 .\"
-.Dd April 5, 2005
+.Dd Nov 6, 2005
 .Dt MATH 3
 .Os
 .if n \{\
@@ -97,6 +97,7 @@ isnormal	determine whether a value is normalized
 frexp	extract exponent and mantissa
 ilogb	extract exponent
 ldexp	multiply by power of 2
+logb	extract exponent
 scalbln	adjust exponent
 scalbn	adjust exponent
 .El