1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
2 .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
3 .\" <mtk.manpages@gmail.com>
5 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
7 .\" References consulted:
8 .\" Linux libc source code
9 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
11 .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
12 .\" Modified 1995-08-14 by Arnt Gulbrandsen <agulbra@troll.no>
13 .\" Modified 2002-07-27 by Walter Harms
14 .\" (walter.harms@informatik.uni-oldenburg.de)
16 .TH EXP 3 2021-03-22 GNU "Linux Programmer's Manual"
18 exp, expf, expl \- base-e exponential function
21 .RI ( libm ", " \-lm )
26 .BI "double exp(double " x );
27 .BI "float expf(float " x );
28 .BI "long double expl(long double " x );
32 Feature Test Macro Requirements for glibc (see
33 .BR feature_test_macros (7)):
39 _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
40 || /* Since glibc 2.19: */ _DEFAULT_SOURCE
41 || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
44 These functions return the value of e (the base of natural
45 logarithms) raised to the power of
48 On success, these functions return the exponential value of
59 positive infinity is returned.
66 If the result underflows,
70 If the result overflows,
72 and the functions return
81 for information on how to determine whether an error has occurred
82 when calling these functions.
84 The following errors can occur:
90 An overflow floating-point exception
94 Range error, underflow
98 An underflow floating-point exception
102 For an explanation of the terms used in this section, see
110 Interface Attribute Value
115 T} Thread safety MT-Safe
121 C99, POSIX.1-2001, POSIX.1-2008.
123 The variant returning