sortix--sortix/libm/man/exp.3

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.\"     from: @(#)exp.3	6.12 (Berkeley) 7/31/91
.\" $FreeBSD: src/lib/msun/man/exp.3,v 1.24 2008/01/18 21:43:00 das Exp $
.\"	$NetBSD: exp.3,v 1.28 2011/09/17 10:52:52 jruoho Exp $
.\"
.Dd September 13, 2011
.Dt EXP 3
.Os
.Sh NAME
.Nm exp ,
.Nm expf ,
.\" The sorting error is intentional.  exp and expf should be adjacent.
.Nm exp2 ,
.Nm exp2f ,
.\" .Nm exp2l ,
.Nm expm1 ,
.Nm expm1f ,
.Nd exponential functions
.Sh LIBRARY
.Lb libm
.Sh SYNOPSIS
.In math.h
.Ft double
.Fn exp "double x"
.Ft float
.Fn expf "float x"
.Ft double
.Fn exp2 "double x"
.Ft float
.Fn exp2f "float x"
.\" .Ft long double
.\" .Fn exp2l "long double x"
.Ft double
.Fn expm1 "double x"
.Ft float
.Fn expm1f "float x"
.Sh DESCRIPTION
The
.Fn exp
and the
.Fn expf
functions compute the base
.Ms e
exponential value of the given argument
.Fa x .
.Pp
The
.Fn exp2 ,
and
.Fn exp2f
.\" .Fn exp2f ,
.\" and
.\" .Fn exp2l
functions compute the base 2 exponential of the given argument
.Fa x .
.Pp
The
.Fn expm1
and the
.Fn expm1f
functions computes the value exp(x)\-1 accurately even for tiny argument
.Fa x .
.Sh RETURN VALUES
These functions will return the appropriate computation unless an error
occurs or an argument is out of range.
The functions
.Fn exp
and
.Fn expm1
detect if the computed value will overflow,
set the global variable
.Va errno
to
.Er ERANGE
and cause a reserved operand fault on a
.Tn VAX .
.Sh SEE ALSO
.Xr math 3
.Sh STANDARDS
The
.Fn exp
functions conform to
.St -ansiC .
The
.Fn exp2 ,
.Fn exp2f ,
.Fn expf ,
.Fn expm1 ,
and
.Fn expm1f
functions conform to
.St -isoC-99 .
.Sh HISTORY
The
.Fn exp
functions appeared in
.At v6 .
The
.Fn expm1
function appeared in
.Bx 4.3 .