# acoshl(3) [posix man page]

ACOSH(P)POSIX Programmer's Manual ACOSH(P)NAME

acosh, acoshf, acoshl - inverse hyperbolic cosine functionsSYNOPSIS

#include <math.h> double acosh(double x); float acoshf(float x); long double acoshl(long double x);DESCRIPTION

These functions shall compute the inverse 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 inverse hyperbolic cosine of their argument. For finite values of x < 1, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value shall be returned. If x is NaN, a NaN shall be returned. If x is +1, +0 shall be returned. If x is +Inf, +Inf shall be returned. If x is, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value shall be returned.-InfERRORS

These functions shall fail if: Domain Error The x argument is finite and less than +1.0, or isIf the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [EDOM]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception shall be raised. The following sections are informative.-Inf.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.RATIONALE

None.FUTURE DIRECTIONS

None.SEE ALSO

cosh() , feclearexcept() , fetestexcept() , the Base Definitions volume of IEEE Std 1003.1-2001, Section 4.18, Treatment of Error Condi- tions 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 Technol- ogyPortable 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 ACOSH(P)

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COSH(P)POSIX Programmer's Manual COSH(P)NAME

cosh, coshf, coshl - hyperbolic cosine functionsSYNOPSIS

#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, Treatment 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 Technol- ogyPortable 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(P)