NAME
exp,
expf,
exp2,
exp2f,
expm1,
expm1f
—
exponential functions
LIBRARY
Math Library (libm, -lm)
SYNOPSIS
#include <math.h>
double
exp(
double
x);
float
expf(
float
x);
double
exp2(
double
x);
float
exp2f(
float
x);
double
expm1(
double
x);
float
expm1f(
float
x);
DESCRIPTION
The
exp() and
expf() functions compute the
base
e exponential value of the given argument
x.
The
exp2() and
exp2f() functions compute the
base 2 exponential of the given argument
x.
The
expm1() and
expm1f() functions compute
the value exp(x)-1 accurately even for tiny argument
x.
RETURN VALUES
These functions will return the appropriate computation unless an error occurs
or an argument is out of range. The functions
exp() and
expm1() detect if the computed value will overflow, set the
global variable
errno to
ERANGE
and cause a reserved operand fault on a VAX.
SEE ALSO
math(3)
STANDARDS
The
exp() function conforms to
ANSI
X3.159-1989 (“ANSI C89”). The
exp2(),
exp2f(),
expf(),
expm1(), and
expm1f() functions conform to
ISO/IEC 9899:1999 (“ISO C99”).
HISTORY
The
exp() functions appeared in
Version 6 AT&T UNIX. The
expm1() function appeared in
4.3BSD.