Content-type: text/html Man page of exp

exp

Section: Mathematical Library Functions (3M)
Updated: 12 Jul 2006
Index Return to Main Contents
 

NAME

exp, expf, expl - exponential function  

SYNOPSIS

c99 [ flag... ] file... -lm [ library... ]
#include <math.h>

double exp(double x);

float expf(float x);

long double expl(long double x);  

DESCRIPTION

These functions compute the base-e exponential of x.  

RETURN VALUES

Upon successful completion, these functions return the exponential value of x.

If the correct value would cause overflow, a range error occurs and exp(), expf(), and expl() return HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively.

If x is NaN, a NaN is returned.

If x is ±0, 1 is returned.

If x is +Inf, x is returned.

For exceptional cases, matherr(3M) tabulates the values to be returned by exp() as specified by SVID3 and XPG3. See standards(5).  

ERRORS

These functions will fail if:

Range Error The result overflows.

If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, the overflow floating-point exception is raised.

The exp() function sets errno to ERANGE if the result overflows.

 

USAGE

An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.

An application can also set errno to 0 before calling exp(). On return, if errno is non-zero, an error has occurred. The expf() and expl() functions do not set errno.  

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPEATTRIBUTE VALUE
Interface StabilityStandard
MT-LevelMT-Safe

 

SEE ALSO

feclearexcept(3M), fetestexcept(3M), isnan(3M), log(3M), math.h(3HEAD), matherr(3M), mp(3MP), attributes(5), standards(5)


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUES
ERRORS
USAGE
ATTRIBUTES
SEE ALSO

This document was created by man2html, using the manual pages.
Time: 02:39:32 GMT, October 02, 2010