man3/exp2.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
   2 .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
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  27 .\" References consulted:
  28 .\"     Linux libc source code
  29 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  30 .\"     386BSD man pages
  31 .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
  32 .\" Modified 1995-08-14 by Arnt Gulbrandsen <agulbra@troll.no>
  33 .\" Modified 2002-07-27 by Walter Harms
  34 .\"     (walter.harms@informatik.uni-oldenburg.de)
  35 .\"
  36 .TH EXP2 3  2017-09-15  "" "Linux Programmer's Manual"
  37 .SH NAME
  38 exp2, exp2f, exp2l \- base-2 exponential function
  39 .SH SYNOPSIS
  40 .nf
  41 .B #include <math.h>
  42 .PP
  43 .BI "double exp2(double " x );
  44 .BI "float exp2f(float " x );
  45 .BI "long double exp2l(long double " x );
  46 .fi
  47 .PP
  48 Link with \fI\-lm\fP.
  49 .PP
  50 .in -4n
  51 Feature Test Macro Requirements for glibc (see
  52 .BR feature_test_macros (7)):
  53 .in
  54 .PP
  55 .ad l
  56 .BR exp2 (),
  57 .BR exp2f (),
  58 .BR exp2l ():
  59 .RS 4
  60 _ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
  61 .RE
  62 .ad b
  63 .SH DESCRIPTION
  64 These functions return the value of 2 raised to the power of
  65 .IR x .
  66 .SH RETURN VALUE
  67 On success, these functions return the base-2 exponential value of
  68 .IR x .
  69 .PP
  70 For various special cases, including the handling of infinity and NaN,
  71 as well as overflows and underflows, see
  72 .BR exp (3).
  73 .SH ERRORS
  74 See
  75 .BR math_error (7)
  76 for information on how to determine whether an error has occurred
  77 when calling these functions.
  78 .PP
  79 For a discussion of the errors that can occur for these functions, see
  80 .BR exp (3).
  81 .SH VERSIONS
  82 These functions first appeared in glibc in version 2.1.
  83 .SH ATTRIBUTES
  84 For an explanation of the terms used in this section, see
  85 .BR attributes (7).
  86 .TS
  87 allbox;
  88 lbw24 lb lb
  89 l l l.
  90 Interface       Attribute       Value
  91 T{
  92 .BR exp2 (),
  93 .BR exp2f (),
  94 .BR exp2l ()
  95 T}      Thread safety   MT-Safe
  96 .TE
  97 .SH CONFORMING TO
  98 C99, POSIX.1-2001, POSIX.1-2008.
  99 .PP
 100 The variant returning
 101 .I double
 102 also conforms to
 103 SVr4, 4.3BSD.
 104 .SH SEE ALSO
 105 .BR cbrt (3),
 106 .BR cexp2 (3),
 107 .BR exp (3),
 108 .BR exp10 (3),
 109 .BR sqrt (3)