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

log2l(3) OSS Library Calls Reference Manual
NAME
log2l - Computes the base-2 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 log2l(
long double x);
PARAMETERS
x Specifies a long double value.
DESCRIPTION
The log2l( ) function is a long double version of the log2( ) function; it takes a long double argu-
ment and returns a long double result.
The log2l( ) function computes the base-2 logarithm of x.
NOTES
This function is implemented only for the IEEE_float floating-point option. Applications using
this function cannot be compiled if the specified floating-point option is Tandem_float.
RETURN VALUES
Upon successful completion, the log2l( ) function returns the base-2 logarithm of x.
If the value of x is positive or negative zero, the log2l( ) function returns HUGE_VALL and sets
errno to [ERANGE].
If the value of x is positive infinity, x is returned. If the value of x is 1, positive zero is returned.
If x is a finite value less than 0 or negative infinity, the log2l( ) function returns NaN and sets
errno to [EDOM].
If the value of x is NaN, NaN is returned.
ERRORS
If any of the following conditions occurs, the log2l( ) function sets errno to the corresponding
value:
[EDOM] The value of x is a finite value less than 0 or negative infinity.
[ERANGE] The value of x is zero.
RELATED INFORMATION
Functions: exp(3), exp10(3), log(3), log1p(3), log2(3), log2f(3), pow(3).
Files: math(4).
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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