Expm1
Defined in header <cmath>
.
Description
Computes the e
(Euler's number, 2.7182818...) raised to the given power num
, minus 1.0. This function is more accurate than the expression
std::exp(num) - 1.0
if num
is close to zero. The library provides overloads of std::expm1
for all cv-unqualified floating-point types as the type of the parameter num
.
Declarations
- C++23
- C++11
// 1)
/* floating-point-type */ expm1( /* floating-point-type */ num );
// 2)
float expm1f( float num );
// 3)
long double expm1l( long double num );
Additional Overloads
// 4)
template< class Integer >
double expm1 ( Integer num );
// 1)
float expm1 ( float num );
// 2)
double expm1 ( double num );
// 3)
long double expm1 ( long double num );
// 4)
float expm1f( float num );
// 5)
long double expm1l( long double num );
Additional Overloads
// 6)
template< class Integer >
double expm1 ( Integer num );
Parameters
num
- floating-point or integer value
Return value
If no errors occur enum -1 is returned.
If a range error due to overflow occurs, +HUGE_VAL
, +HUGE_VALF
, or +HUGE_VALL
is returned.
If a range error occurs due to underflow, the correct result (after rounding) is returned.
Error handling
Errors are reported as specified in math_errhandling.
If the implementation supports IEEE floating-point arithmetic (IEC 60559):
- If the argument is