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EXP(3) Linux Programmer's Manual EXP(3)

NAME

exp, expf, expl - base-e exponential function

SYNOPSIS

#include <math.h>
 
double exp(double x);
 
float expf(float x);
 
long double expl(long double x);
 
Link with -lm.
 

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
 
expf(), expl():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
 
or cc -std=c99

DESCRIPTION

The exp() function returns the value of e (the base of natural logarithms) raised to the power of x.

RETURN VALUE

On success, these functions return the exponential value of x.
 
If x is a NaN, a NaN is returned.
 
If x is positive infinity, positive infinity is returned.
 
If x is negative infinity, +0 is returned.
 
If the result underflows, a range error occurs, and zero is returned.
 
If the result overflows, a range error occurs, and the functions return +HUGE_VAL, +HUGE_VALF, or +HUGE_VALL, respectively.

ERRORS

See math_error(7) for information on how to determine whether an error has occurred when calling these functions.
 
The following errors can occur:
Range error, overflow
errno is set to ERANGE. An overflow floating-point exception (FE_OVERFLOW) is raised.
Range error, underflow
errno is set to ERANGE. An underflow floating-point exception (FE_UNDERFLOW) is raised.

CONFORMING TO

C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD, C89.

SEE ALSO

cbrt(3), cexp(3), exp10(3), exp2(3), sqrt(3)

COLOPHON

This page is part of release 3.44 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.
2010-09-20