cmsg.3: Explain zero-initialization requirement for CMSG_NXTHDR()

[thirdparty/man-pages.git] / man3 / exp2.3

.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
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.\" References consulted:
.\"     Linux libc source code
.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\"     386BSD man pages
.\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
.\" Modified 1995-08-14 by Arnt Gulbrandsen <agulbra@troll.no>
.\" Modified 2002-07-27 by Walter Harms
.\" 	(walter.harms@informatik.uni-oldenburg.de)
.\"
.TH EXP2 3  2017-09-15  "" "Linux Programmer's Manual"
.SH NAME
exp2, exp2f, exp2l \- base-2 exponential function
.SH SYNOPSIS
.nf
.B #include <math.h>
.PP
.BI "double exp2(double " x );
.BI "float exp2f(float " x );
.BI "long double exp2l(long double " x );
.fi
.PP
Link with \fI\-lm\fP.
.PP
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.PP
.ad l
.BR exp2 (),
.BR exp2f (),
.BR exp2l ():
.RS 4
_ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
.RE
.ad b
.SH DESCRIPTION
These functions return the value of 2 raised to the power of
.IR x .
.SH RETURN VALUE
On success, these functions return the base-2 exponential value of
.IR x .
.PP
For various special cases, including the handling of infinity and NaN,
as well as overflows and underflows, see
.BR exp (3).
.SH ERRORS
See
.BR math_error (7)
for information on how to determine whether an error has occurred
when calling these functions.
.PP
For a discussion of the errors that can occur for these functions, see
.BR exp (3).
.SH VERSIONS
These functions first appeared in glibc in version 2.1.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbw24 lb lb
l l l.
Interface	Attribute	Value
T{
.BR exp2 (),
.BR exp2f (),
.BR exp2l ()
T}	Thread safety	MT-Safe
.TE
.SH CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
.PP
The variant returning
.I double
also conforms to
SVr4, 4.3BSD.
.SH SEE ALSO
.BR cbrt (3),
.BR cexp2 (3),
.BR exp (3),
.BR exp10 (3),
.BR sqrt (3)