COSH(3P) POSIX Programmer s Manual COSH(3P)

PROLOG This manual page is part of the POSIX Programmer s Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME cosh, coshf, coshl - hyperbolic cosine functions

SYNOPSIS #include <math.h>

double cosh(double x); float coshf(float x); long double coshl(long double x);

DESCRIPTION These functions shall compute the hyperbolic cosine of their argument x.

An application wishing to check for error situations should set errno to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if errno is non-zero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.

RETURN VALUE 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(), and coshl() shall return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively.

If x is NaN, a NaN shall be returned.

If x is ±0, the value 1.0 shall be returned.

If x is ±Inf, +Inf shall be returned.

ERRORS These functions shall fail if:

Range Error The result would cause an overflow.

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

The following sections are informative.

EXAMPLES None.

APPLICATION USAGE 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 that cosh( x) has overflowed.

RATIONALE None.

FUTURE DIRECTIONS None.

SEE ALSO acosh(), feclearexcept(), fetestexcept(), isnan(), sinh(), tanh(), the Base Definitions volume of IEEE Std 1003.1-2001, Section 4.18, Treat- ment of Error Conditions for Mathematical Functions, <math.h>

COPYRIGHT Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group 2003 COSH(3P)