Module Name: src
Committed By: jruoho
Date: Mon Sep 12 14:44:27 UTC 2011
Modified Files:
src/lib/libm/man: ldexp.3
Log Message:
Update and improve, and note that the long double variant is not supported.
To generate a diff of this commit:
cvs rdiff -u -r1.1 -r1.2 src/lib/libm/man/ldexp.3
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libm/man/ldexp.3
diff -u src/lib/libm/man/ldexp.3:1.1 src/lib/libm/man/ldexp.3:1.2
--- src/lib/libm/man/ldexp.3:1.1 Mon Jul 3 16:03:56 2006
+++ src/lib/libm/man/ldexp.3 Mon Sep 12 14:44:27 2011
@@ -1,4 +1,4 @@
-.\" $NetBSD: ldexp.3,v 1.1 2006/07/03 16:03:56 drochner Exp $
+.\" $NetBSD: ldexp.3,v 1.2 2011/09/12 14:44:27 jruoho Exp $
.\"
.\" Copyright (c) 1991, 1993
.\" The Regents of the University of California. All rights reserved.
@@ -33,11 +33,12 @@
.\"
.\" @(#)ldexp.3 8.2 (Berkeley) 4/19/94
.\"
-.Dd March 21, 2006
+.Dd September 12, 2011
.Dt LDEXP 3
.Os
.Sh NAME
-.Nm ldexp
+.Nm ldexp ,
+.Nm ldexpf
.Nd multiply floating-point number by integral power of 2
.Sh LIBRARY
.Lb libm
@@ -50,40 +51,57 @@
.Sh DESCRIPTION
The
.Fn ldexp
-function multiplies a floating-point number by an integral
-power of 2.
+family of functions compute
+.Bd -ragged -offset indent
+.Va x
+*
+2^\fIexp\fR
+.Ed
+.Pp
+for a real floating-point number
+.Fa x .
.Sh RETURN VALUES
-The
-.Fn ldexp
-function returns the value of
+The functions return the value of
.Fa x
times 2 raised to the power
.Fa exp .
-.Pp
-If the input
-.Va x
-is a NaN, infinity, or 0.0, it is returned unchanged.
-.Pp
-If the result would cause an overflow,
-the global variable
-.Va errno
-is set to
-.Er ERANGE
-and infinity is returned, with the same sign as
-.Fa x .
-.Pp
-If the result would cause underflow to 0.0,
-the global variable
-.Va errno
-is set to
-.Er ERANGE
-and the value 0.0 is returned.
+Otherwise the following may occur:
+.Bl -enum -offset indent
+.It
+If
+.Fa x
+is \*(Na , a \*(Na is returned.
+.It
+If
+.Fa exp
+is zero or
+.Fa x
+is either \*(Pm\* 0 or \*(Pm\* Inf,
+.Fa x
+is returned.
+.It
+If the call would cause an overflow, a range error occurs and either
+.Dv \*(Pm\*HHUGE_VAL ,
+.Dv \*(Pm\*HHUGE_VALF ,
+or
+.Dv \*(Pm\*HHUGE_VALL
+is returned, depending on the sign of
+.Fa x
+and the type of the return value.
+.It
+If an underflow would be caused by the correct value,
+and the value is not representable, either 0.0 or
+an implementation-defined value is returned.
+.El
.Sh SEE ALSO
.Xr frexp 3 ,
.Xr math 3 ,
.Xr modf 3
.Sh STANDARDS
+The described functions conform to
+.St -isoC-99 .
+.Sh BUGS
The
-.Fn ldexp
-function conforms to
-.St -ansiC .
+.Vt long double
+variant is not supported in
+.Nx .
