exp(3M) Mathematical Library Functions exp(3M)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 feclearex‐
cept(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 TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Standard │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOfeclearexcept(3M), fetestexcept(3M), isnan(3M), log(3M), math.h(3HEAD),
matherr(3M), mp(3MP), attributes(5), standards(5)SunOS 5.10 12 Jul 2006 exp(3M)