1.\" Copyright (c) 1985, 1991 Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" from: @(#)exp.3 6.12 (Berkeley) 7/31/91 29.\" $FreeBSD: src/lib/msun/man/exp.3,v 1.24 2008/01/18 21:43:00 das Exp $ 30.\" $NetBSD: exp.3,v 1.33 2024/01/26 19:27:30 nros Exp $ 31.\" 32.Dd January 24, 2024 33.Dt EXP 3 34.Os 35.Sh NAME 36.Nm exp , 37.Nm expf , 38.Nm expl , 39.\" The sorting error is intentional. exp and expf should be adjacent. 40.Nm exp2 , 41.Nm exp2f , 42.Nm exp2l , 43.Nm expm1 , 44.Nm expm1f 45.Nm expm1l 46.Nd exponential functions 47.Sh LIBRARY 48.Lb libm 49.Sh SYNOPSIS 50.In math.h 51.Ft double 52.Fn exp "double x" 53.Ft float 54.Fn expf "float x" 55.Ft long double 56.Fn expf "long double x" 57.Ft double 58.Fn exp2 "double x" 59.Ft float 60.Fn exp2f "float x" 61.Ft long double 62.Fn exp2l "long double x" 63.Ft double 64.Fn expm1 "double x" 65.Ft float 66.Fn expm1f "float x" 67.Ft long double 68.Fn expm1l "long double x" 69.Sh DESCRIPTION 70The 71.Fn exp , 72.Fn expf , 73and 74.Fn expl 75functions compute the base 76.Ms e 77exponential value of the given argument 78.Fa x . 79.Pp 80The 81.Fn exp2 , 82.Fn exp2f , 83and 84.Fn exp2l 85functions compute the base 2 exponential of the given argument 86.Fa x . 87.Pp 88The 89.Fn expm1 , 90.Fn expm1f 91and 92.Fn expm1l 93functions compute the value exp(x)\-1 accurately even for tiny argument 94.Fa x . 95.Sh RETURN VALUES 96These functions will return the appropriate computation unless an error 97occurs or an argument is out of range. 98The functions 99.Fn exp 100and 101.Fn expm1 102detect if the computed value will overflow, 103set the global variable 104.Va errno 105to 106.Er ERANGE 107and cause a reserved operand fault on a 108.Tn VAX . 109.Sh SEE ALSO 110.Xr math 3 111.Sh STANDARDS 112The 113.Fn exp 114function conforms to 115.St -ansiC . 116The 117.Fn exp2 , 118.Fn exp2f , 119.Fn exp2l , 120.Fn expf , 121.Fn expl , 122.Fn expm1 , 123.Fn expm1f , 124and 125.Fn expm1l 126functions conform to 127.St -isoC-99 . 128.Sh HISTORY 129The 130.Fn exp 131functions appeared in 132.At v1 . 133The 134.Fn expm1 135function appeared in 136.Bx 4.3 . 137