std::expm1

 

C++

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Basic operations
abs(int) labs llabs imaxabs (C++11) abs(float) fabs div ldiv lldiv imaxdiv (C++11) fmod	remainder (C++11) remquo (C++11) fma (C++11) fmax (C++11) fmin (C++11) fdim (C++11) nan nanf nanl (C++11) (C++11) (C++11)
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erf (C++11) erfc (C++11)	lgamma (C++11) tgamma (C++11)
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ceil floor round lround llround (C++11) (C++11) (C++11)	trunc (C++11) nearbyint (C++11) rint lrint llrint (C++11) (C++11) (C++11)
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ldexp scalbn scalbln (C++11) (C++11) ilogb (C++11) logb (C++11)	frexp modf nextafter nexttoward (C++11) (C++11) copysign (C++11)
Classification/Comparison
fpclassify (C++11) isfinite (C++11) isinf (C++11) isnan (C++11) isnormal (C++11) signbit (C++11)	isgreater (C++11) isgreaterequal (C++11) isless (C++11) islessequal (C++11) islessgreater (C++11) isunordered (C++11)
Macro constants
HUGE_VALF HUGE_VAL HUGE_VALL (C++11) (C++11) INFINITY (C++11) NAN (C++11) math_errhandling MATH_ERRNO MATH_ERREXCEPT (C++11)	FP_NORMAL FP_SUBNORMAL FP_ZERO FP_INFINITE FP_NAN (C++11) (C++11) (C++11) (C++11) (C++11)

 

Defined in header <cmath>
float       expm1( float arg );		(since C++11)
double      expm1( double arg );		(since C++11)
long double expm1( long double arg );		(since C++11)
double      expm1( Integral arg );		(since C++11)

Computes the e (Euler's number, 2.7182818) raised to the given power arg, minus 1. This function is more accurate than the expression std::exp(arg)-1 if arg is close to zero.

Parameters

arg

-

floating point value

Return value

earg
-1

If the result is too large for the underlying type, range error occurs and HUGE_VAL is returned.

See also

exp	returns e raised to the given power (ex) (function)
log1p (C++11)	natural logarithm (to base e) of 1 plus the given number (function)
exp2 (C++11)	returns 2 raised to the given power (2x) (function)