Guardian Native C Library Calls Reference Manual (G06.28+, H06.05+)

exp(3) Guardian Native C Library Calls Reference Manual
NAME
exp - Computes the exponential function
LIBRARY
G-series native Guardian processes: $SYSTEM.SYSnn.ZCRESRL
G-series native OSS processes: /G/system/sysnn/zcresrl
H-series native Guardian processes: $SYSTEM.ZDLLnnn.ZCREDLL
H-series OSS processes: /G/system/zdllnnn/zcredll
SYNOPSIS
#include <math.h>
double exp(
double x);
PARAMETERS
x Specifies the power to which the base of the natural logarithms (e)istoberaised.
DESCRIPTION
The exp() function computes the exponential function of x, defined as e
x
, where e is the constant
used as a base for natural logarithms.
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
Upon successful completion, exp() returns the value of the exponential function of x. If the
correct value would cause overflow, the exp() function returns HUGE_VAL and sets errno to
[ERANGE]. If the correct value would cause underflow, the exp() function returns a value of 0.0
(zero) and sets errno to [ERANGE].
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.
ERRORS
If any of the following conditions occurs, the exp() function sets errno to the corresponding
value:
[ERANGE] The result would cause underflow or overflow.
RELATED INFORMATION
Functions: expm1(3), fp_class(3), isnan(3), log(3), log10(3), pow(3), sinh(3).
STANDARDS CONFORMANCE
This function conforms to the XPG4 Version 2 specification with extensions when used for IEEE
floating-point format data. This function conforms to the XPG4 Version 2 specification without
extensions when used for Tandem floating-point data.
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