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

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

.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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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 1996-06-08 by aeb
.\" Modified 2002-07-27 by Walter Harms
.\" (walter.harms@informatik.uni-oldenburg.de)
.\"
.TH COSH 3 2017-09-15 ""  "Linux Programmer's Manual"
.SH NAME
cosh, coshf, coshl \- hyperbolic cosine function
.SH SYNOPSIS
.nf
.B #include <math.h>
.PP
.BI "double cosh(double " x );
.BI "float coshf(float " x );
.BI "long double coshl(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 coshf (),
.BR coshl ():
.RS 4
_ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
    || /* Since glibc 2.19: */ _DEFAULT_SOURCE
    || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
.RE
.ad
.SH DESCRIPTION
These functions return the hyperbolic cosine of
.IR x ,
which is defined mathematically as:
.PP
.nf
    cosh(x) = (exp(x) + exp(\-x)) / 2
.fi
.SH RETURN VALUE
On success, these functions return the hyperbolic cosine of
.IR x .
.PP
If
.I x
is a NaN, a NaN is returned.
.PP
If
.I x
is +0 or \-0, 1 is returned.
.PP
If
.I x
is positive infinity or negative infinity,
positive infinity is returned.
.PP
If the result overflows,
a range error occurs,
and the functions return
.RB + HUGE_VAL ,
.RB + HUGE_VALF ,
or
.RB + HUGE_VALL ,
respectively.
.SH ERRORS
See
.BR math_error (7)
for information on how to determine whether an error has occurred
when calling these functions.
.PP
The following errors can occur:
.TP
Range error: result overflow
.I errno
is set to
.BR ERANGE .
An overflow floating-point exception
.RB ( FE_OVERFLOW )
is raised.
.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 cosh (),
.BR coshf (),
.BR coshl ()
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 BUGS
In glibc version 2.3.4 and earlier,
an overflow floating-point
.RB ( FE_OVERFLOW  )
exception is not raised when an overflow occurs.
.SH SEE ALSO
.BR acosh (3),
.BR asinh (3),
.BR atanh (3),
.BR ccos (3),
.BR sinh (3),
.BR tanh (3)