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

logl(3) OSS Library Calls Reference Manual
NAME
logl - Computes the natural logarithm 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 logl(
long double x);
PARAMETERS
x Specifies a long double value.
DESCRIPTION
The logl( ) function is a long double version of the log( ) function; it takes a long double argu-
ment and returns a long double result.
The logl( ) function computes the natural logarithm of x.
NOTES
This function supports both IEEE Std 754-1985 floating-point and Tandem floating-point values
in the native environment. 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 logl( ) function returns the natural logarithm of x. The value of x must be positive.
For IEEE floating-point data, if the value of x is NaN, NaN is returned. If the value of x is posi-
tive infinity, positive infinity is returned.
If x is negative, either - HUGE_VALL is returned for Tandem floating-point data or NaN is
returned for IEEE floating-point data, and errno is set to [EDOM]. If x is 0.0 (zero),
- HUGE_VALL is returned and errno is set to [ERANGE].
ERRORS
If any of the following conditions occurs, the logl( ) function sets errno to the corresponding
value:
[EDOM] The value of x is negative.
[ERANGE] The value of x is 0.0 (zero).
RELATED INFORMATION
Functions: exp(3), fp_class(3), isnan(3), log(3), logf(3), log10(3), pow(3), sinh(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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