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 .\" Permission is granted to make and distribute verbatim copies of this
6 .\" manual provided the copyright notice and this permission notice are
7 .\" preserved on all copies.
9 .\" Permission is granted to copy and distribute modified versions of this
10 .\" manual under the conditions for verbatim copying, provided that the
11 .\" entire resulting derived work is distributed under the terms of a
12 .\" permission notice identical to this one.
14 .\" Since the Linux kernel and libraries are constantly changing, this
15 .\" manual page may be incorrect or out-of-date. The author(s) assume no
16 .\" responsibility for errors or omissions, or for damages resulting from
17 .\" the use of the information contained herein. The author(s) may not
18 .\" have taken the same level of care in the production of this manual,
19 .\" which is licensed free of charge, as they might when working
22 .\" Formatted or processed versions of this manual, if unaccompanied by
23 .\" the source, must acknowledge the copyright and authors of this work.
25 .\" References consulted:
26 .\" Linux libc source code
27 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
29 .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
30 .\" Modified 2004-10-31 by aeb
32 .TH LDEXP 3 2010-09-20 "" "Linux Programmer's Manual"
34 ldexp, ldexpf, ldexpl \- multiply floating-point number by integral power of 2
39 .BI "double ldexp(double " x ", int " exp );
41 .BI "float ldexpf(float " x ", int " exp );
43 .BI "long double ldexpl(long double " x ", int " exp );
49 Feature Test Macro Requirements for glibc (see
50 .BR feature_test_macros (7)):
57 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE ||
58 _POSIX_C_SOURCE\ >=\ 200112L;
67 function returns the result of multiplying the floating-point number
69 by 2 raised to the power
72 On success, these functions return
88 is positive infinity (negative infinity),
89 positive infinity (negative infinity) is returned.
91 If the result underflows,
92 an range error occurs,
95 If the result overflows,
97 and the functions return
102 respectively, with a sign the same as
107 for information on how to determine whether an error has occurred
108 when calling these functions.
110 The following errors can occur:
112 Range error, overflow
116 An overflow floating-point exception
120 Range error, underflow
124 An underflow floating-point exception
129 The variant returning