man3/exp2.3

   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>
   4 .\"
   5 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
   6 .\"
   7 .\" References consulted:
   8 .\"     Linux libc source code
   9 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  10 .\"     386BSD man pages
  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)
  15 .\"
  16 .TH exp2 3 (date) "Linux man-pages (unreleased)"
  17 .SH NAME
  18 exp2, exp2f, exp2l \- base-2 exponential function
  19 .SH LIBRARY
  20 Math library
  21 .RI ( libm ", " \-lm )
  22 .SH SYNOPSIS
  23 .nf
  24 .B #include <math.h>
  25 .PP
  26 .BI "double exp2(double " x );
  27 .BI "float exp2f(float " x );
  28 .BI "long double exp2l(long double " x );
  29 .fi
  30 .PP
  31 .RS -4
  32 Feature Test Macro Requirements for glibc (see
  33 .BR feature_test_macros (7)):
  34 .RE
  35 .PP
  36 .BR exp2 (),
  37 .BR exp2f (),
  38 .BR exp2l ():
  39 .nf
  40     _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
  41 .fi
  42 .SH DESCRIPTION
  43 These functions return the value of 2 raised to the power of
  44 .IR x .
  45 .SH RETURN VALUE
  46 On success, these functions return the base-2 exponential value of
  47 .IR x .
  48 .PP
  49 For various special cases, including the handling of infinity and NaN,
  50 as well as overflows and underflows, see
  51 .BR exp (3).
  52 .SH ERRORS
  53 See
  54 .BR math_error (7)
  55 for information on how to determine whether an error has occurred
  56 when calling these functions.
  57 .PP
  58 For a discussion of the errors that can occur for these functions, see
  59 .BR exp (3).
  60 .SH VERSIONS
  61 These functions first appeared in glibc in version 2.1.
  62 .SH ATTRIBUTES
  63 For an explanation of the terms used in this section, see
  64 .BR attributes (7).
  65 .ad l
  66 .nh
  67 .TS
  68 allbox;
  69 lbx lb lb
  70 l l l.
  71 Interface       Attribute       Value
  72 T{
  73 .BR exp2 (),
  74 .BR exp2f (),
  75 .BR exp2l ()
  76 T}      Thread safety   MT-Safe
  77 .TE
  78 .hy
  79 .ad
  80 .sp 1
  81 .SH STANDARDS
  82 C99, POSIX.1-2001, POSIX.1-2008.
  83 .PP
  84 The variant returning
  85 .I double
  86 also conforms to
  87 SVr4, 4.3BSD.
  88 .SH SEE ALSO
  89 .BR cbrt (3),
  90 .BR cexp2 (3),
  91 .BR exp (3),
  92 .BR exp10 (3),
  93 .BR sqrt (3)