Open System Services Library Calls Reference Manual (G06.29+, H06.08+, J06.03+)

OSS Library Calls (a - d) acoshf(3)
NAME
acoshf - Computes the inverse hyperbolic cosine function for a float value
LIBRARY
H-series and J-series native Guardian processes: $SYSTEM.ZDLLnnn.ZCREDLL
32-bit H-series and J-series OSS processes: /G/system/zdllnnn/zcredll
64-bit H-series and J-series OSS processes: /G/system/zdllnnn/ycredll
SYNOPSIS
#include <math.h>
float acoshf(
float x);
PARAMETERS
x Is the float value for which the inverse hyperbolic cosine function is to be com-
puted.
DESCRIPTION
The acoshf( ) function is a float version of the acosh( ) function; it takes a float argument and
returns a float result.
The acoshf( ) function computes the inverse hyperbolic cosine of x.
The acoshf( ) function can be called only by native processes.
NOTES
This function supports both IEEE Std 754-1985 floating-point and Tandem floating-point values.
IEEE values can include NaN and infinity, and the sign of 0.0 (zero) can be either positive or
negative. Refer to the fp_class(3) reference page for a description of IEEE value classes.
Guardian functions are available to convert between floating-point formats. Refer to the Guar-
dian Programmer’s Guide for a discussion of floating-point conversions.
RETURN VALUES
The acoshf( ) function returns the inverse hyperbolic cosine of the x parameter.
For IEEE floating-point values, when the value of x is NaN, the acoshf( ) function returns NaN.
When the value of x is positive infinity, the acoshf( ) function returns positive infinity. When the
value of x is less than 1.0, the acoshf( ) function returns NaN and sets errno to [EDOM]. When
the value of x is negative infinity, the acoshf( ) function returns NaN and sets errno to [EDOM].
For Tandem floating-point values, when the value of x is less than 1.0, the acoshf( ) function
returns -HUGE_VALF and sets errno to [EDOM].
ERRORS
If the following condition occurs, the acoshf( ) function sets errno to the corresponding value:
[EDOM] The value of the x parameter is less than 1.0 or, for IEEE floating-point values,
the value of x is negative infinity.
RELATED INFORMATION
Functions: acosh(3), acoshl(3), asinh(3), atanh(3), cacosh(3), cosh(3), fp_class(3), isnan(3).
STANDARDS CONFORMANCE
This function conforms to the ISO/IEC 9899:1999 standard.
This function conforms to the IEEE Std 1003.1, 2004 Edition.
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