EXP(3M) Mathematical Library Functions EXP(3M)
exp, expf, expl - exponential function
c99 [ flag... ] file... -lm [ library... ]
#include <math.h>
double exp(double x);
float expf(float x);
long double expl(long double x);
These functions compute the base-e exponential of x.
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(7).
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.
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.
See attributes(7) for descriptions of the following attributes:
+----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+----------------------------+-----------------------------+
|Interface Stability | Standard |
+----------------------------+-----------------------------+
|MT-Level | MT-Safe |
+----------------------------+-----------------------------+
math.h(3HEAD), feclearexcept(3M), fetestexcept(3M), isnan(3M),
log(3M), matherr(3M), mp(3MP), attributes(7), standards(7)
SunOS 5.11 July 12, 2006 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(7).
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(7) for descriptions of the following attributes:
+----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+----------------------------+-----------------------------+
|Interface Stability | Standard |
+----------------------------+-----------------------------+
|MT-Level | MT-Safe |
+----------------------------+-----------------------------+
SEE ALSO
math.h(3HEAD), feclearexcept(3M), fetestexcept(3M), isnan(3M),
log(3M), matherr(3M), mp(3MP), attributes(7), standards(7)
SunOS 5.11 July 12, 2006 EXP(3M)