# expm1(3) [opendarwin man page]

```EXP(3)							   BSD Library Functions Manual 						    EXP(3)

NAME
exp, exp2, expm1 -- exponential functions

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() function computes e**x, the base-e exponential of x.

The exp2() function computes 2**x, the base-2 exponential of x.

The expm1() function computes the base-e exponential of x , minus 1 accurately even for very small values of x.

SPECIAL VALUES
exp(+-0) and exp2(+-0) return 1.

exp(-infinity) and exp2(-infinity) return +0.

exp(+infinity) and exp2(+infinity) return +infinity.

expm1(+-0) returns +-0.

expm1(-infinity) returns -1.

expm1(+infinity) returns +infinity.

For all these functions, a range error occurs if the magnitude of x is too large.

math(3), infnan(3)

STANDARDS
The exp() , expf() , exp2() , exp2f() , expm1() , and expm1f() functions conform to ISO/IEC 9899:1999(E).

4th Berkeley Distribution					 January 30, 2003					 4th Berkeley Distribution```

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```EXP(3)							   BSD Library Functions Manual 						    EXP(3)

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 the 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 the expm1f() functions computes 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.