NAME
exp, expf,
exp2, exp2f,
expm1, expm1f —
exponential functions
LIBRARY
library “libm”
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
Theexp()
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
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 1 AT&T UNIX. The
expm1() function appeared in
4.3BSD.