IEEE Std 1003.1-2008

Copyright © 2001-2008 The IEEE and The Open Group

cosh, coshf, coshl - hyperbolic cosine functions

#include <math.h>

double cosh(doublex);

float coshf(floatx);

long double coshl(long doublex);

^{[CX]}The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2008 defers to the ISO C standard.These functions shall compute the hyperbolic cosine of their argument

x.An application wishing to check for error situations should set

errnoto zero and callfeclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, iferrnois non-zero orfetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.

Upon successful completion, these functions shall return the hyperbolic cosine of

x.If the correct value would cause overflow, a range error shall occur and

cosh(),coshf(), andcoshl() shall return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively.

^{[MX]}Ifxis NaN, a NaN shall be returned.If

xis ±0, the value 1.0 shall be returned.If

xis ±Inf, +Inf shall be returned.

These functions shall fail if:

- Range Error
- The result would cause an overflow.
If the integer expression (

math_errhandling& MATH_ERRNO) is non-zero, thenerrnoshall be set to [ERANGE]. If the integer expression (math_errhandling& MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception shall be raised.

None.

On error, the expressions (

math_errhandling& MATH_ERRNO) and (math_errhandling& MATH_ERREXCEPT) are independent of each other, but at least one of them must be non-zero.For IEEE Std 754-1985

double, 710.5 < |x| implies thatcosh(x) has overflowed.

None.

None.

acosh,feclearexcept,fetestexcept,isnan,sinh,tanhXBD

Treatment of Error Conditions for Mathematical Functions,<math.h>

First released in Issue 1. Derived from Issue 1 of the SVID.

The DESCRIPTION is updated to indicate how an application should check for an error. This text was previously published in the APPLICATION USAGE section.

The

coshf() andcoshl() functions are added for alignment with the ISO/IEC 9899:1999 standard.The DESCRIPTION, RETURN VALUE, ERRORS, and APPLICATION USAGE sections are revised to align with the ISO/IEC 9899:1999 standard.

IEC 60559:1989 standard floating-point extensions over the ISO/IEC 9899:1999 standard are marked.

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