HP-UX Reference (11i v1 00/12) - 3 Library Functions A-M (vol 6)
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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man3/!!!intro.3c
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e
exp(3M) 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 speci-
fying -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.
SEE ALSO
cbrt(3M), exp2(3M), expm1(3M), log(3M), pow(3M), sqrt(3M), math(5), values(5).
STANDARDS CONFORMANCE
exp(): SVID3, XPG4.2, ANSI C
Section 3−−210 − 1 − HP-UX Release 11i: December 2000
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