diff --git a/lib/msun/man/erf.3 b/lib/msun/man/erf.3
index d5be06036ce9..8d66017ed11c 100644
--- a/lib/msun/man/erf.3
+++ b/lib/msun/man/erf.3
@@ -1,95 +1,106 @@
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-.Dd July 13, 2014
+.Dd June 23, 2024
 .Dt ERF 3
 .Os
 .Sh NAME
 .Nm erf ,
 .Nm erff ,
 .Nm erfl ,
 .Nm erfc ,
 .Nm erfcf ,
 .Nm erfcl
 .Nd error function operators
 .Sh LIBRARY
 .Lb libm
 .Sh SYNOPSIS
 .In math.h
 .Ft double
 .Fn erf "double x"
 .Ft float
 .Fn erff "float x"
 .Ft "long double"
 .Fn erfl "long double x"
 .Ft double
 .Fn erfc "double x"
 .Ft float
 .Fn erfcf "float x"
 .Ft "long double"
 .Fn erfcl "long double x"
 .Sh DESCRIPTION
 These functions calculate the error function of
 .Fa x .
 .Pp
 The
 .Fn erf ,
 .Fn erff ,
 and
 .Fn erfl
 functions calculate the error function of x; where
 .Bd -ragged -offset indent
 .if n \{\
 erf(x) = 2/sqrt(pi)\(**\|integral from 0 to x of exp(\-t\(**t) dt.
 \}
 .if t \{\
 erf\|(x) :=
 (2/\(sr\(*p)\|\(is\d\s8\z0\s10\u\u\s8x\s10\d\|exp(\-t\u\s82\s10\d)\|dt.
 \}
 .Ed
 .Pp
 The
 .Fn erfc ,
 .Fn erfcf ,
 and
 .Fn erfcl
 functions calculate the complementary error function of
 .Fa x ;
 that is
 .Fn erfc
 subtracts the result of the error function
 .Fn erf x
 from 1.0.
 .Sh SEE ALSO
 .Xr math 3
+.Sh STANDARDS
+The
+.Fn erf ,
+.Fn erff ,
+.Fn erfl ,
+.Fn erfc ,
+.Fn erfcf
+and
+.Fn erfcl
+functions conform to
+.St -isoC-99 .
 .Sh HISTORY
 The
 .Fn erf
 and
 .Fn erfc
 functions appeared in
 .Bx 4.3 .