exp(3M)

NAME

exp(), expf() — exponential functions

SYNOPSIS

#include <math.h>

double exp(double x);

float expf(float x);

DESCRIPTION

exp() returns e^x.

expf() is a float version of exp(); it takes a float argument and returns a float result. To use this function, compile either with the default -Ae option or with the -Aa and -D_HPUX_SOURCE options.

expf() is not specified by any standard, but it is named in accordance with the conventions specified in the "Future Library Directions" section of the ANSI C standard.

To use these functions, make sure your program includes <math.h>, and link in the math library by specifying -lm on the compiler or linker command line.

Millicode versions of the exp() function are available. Millicode versions of math library functions are usually faster than their counterparts in the standard library. To use these versions, compile your program with the +Olibcalls or the +Oaggressive optimization option.

If an error occurs, the millicode versions return the value described in the RETURN VALUE section, but do not set errno.

For more information, see the HP-UX Floating-Point Guide.

RETURN VALUE

If x is +INFINITY, exp() returns +INFINITY.

If x is -INFINITY, exp() returns zero.

If x is NaN, exp() returns NaN.

If the correct value after rounding would be smaller in magnitude than MINDOUBLE, exp() returns zero.

If the correct value would overflow, exp() returns HUGE_VAL and sets errno to [ERANGE].

ERRORS

If exp() fails, errno is set to the following value.

[ERANGE]: The correct value would overflow.

STANDARDS CONFORMANCE

exp(): SVID3, XPG4.2, ANSI C

exp(3M)

Technical documentation

» Table of Contents

» Index