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

OSS Library Calls (e - f) erfcl(3)
NAME
erfcl - Computes the complementary error function for a long double 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>
long double erfcl(
long double x);
PARAMETERS
x Specifies the long double value for which the complementary error function is to
be computed.
DESCRIPTION
The erfcl( ) function is a long double version of the erfc( ) function; it takes a long double argu-
ment and returns a long double result.
The erfcl( ) function computes 1.0 - erfl(x).
The erfcl( ) function is provided because of the significant loss of relative accuracy if erfl(x)is
called for large values of x and the result is subtracted from 1.0. For example, 12 decimal places
are lost when calculating (1.0 - erfl(5)).
NOTES
The erfcl( ) function can be called only by native processes.
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
Upon successful completion, the erfcl( ) function returns the value of the complementary error
function.
For IEEE floating-point data, when the value of x is NaN, NaN is returned.
If the correct result would cause underflow, 0.0 (zero) is returned.
ERRORS
No errors are returned. This function does not set errno.
RELATED INFORMATION
Functions: erf(3), erfc(3), erfcf(3), exp(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.
527187-017 Hewlett-Packard Company 2−19