exp(), expf(), expm1(), expm1f() exponential functions	Function
	SYNOPSIS DESCRIPTION PARAMETERS RETURN VALUES CONFORMANCE MULTITHREAD SAFETY LEVEL PORTING ISSUES AVAILABILITY SEE ALSO

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SYNOPSIS

#include <math.h>

double exp(double x)

float expf(float x)

double expm1(double x)

float expm1f(float x)

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DESCRIPTION

The exp() function computes the exponent of x, e^x.

The expm1() function returns e^x-1.0.

To check for error situations, set errno to 0 before calling exp(). If errno is non-zero on return, or the return value is NaN, an error has occurred.

The expf() and expm1f() functions are single-precision versions of exp() and expm1().

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PARAMETERS

x 

Is a floating point value.

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RETURN VALUES

The exp() function returns e^x.

The expm1() function returns e^x-1.0.

If the return value would overflow, one of the following occurs:

• In IEEE mode, Inf is returned.

• In POSIX mode, Inf is returned and errno is set to ERANGE.

• In SVID mode, HUGE_VAL is returned and matherr() is called.

• In XOPEN mode, Inf is returned and matherr() is called.

If the return value would underflow, 0.0 is returned and:

• In POSIX mode, errno is set to ERANGE.

• In SVID or XOPEN mode, matherr() is called.

If x is NaN, NaN is returned.

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CONFORMANCE

exp(): ANSI/ISO 9899-1990

expm1(): UNIX 98.

expf(), expm1f(): MKS Toolkit UNIX APIs extension

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MULTITHREAD SAFETY LEVEL

MT-Safe.

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PORTING ISSUES

At high levels of compiler optimizations, the hardware handles the exp() function intrinsically. In such cases, mathematical exceptions do not cause the matherr() function to be called or the errno value to be set.

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AVAILABILITY

MKS Toolkit for Professional Developers
MKS Toolkit for Enterprise Developers
MKS Toolkit for Enterprise Developers 64-Bit Edition

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SEE ALSO

Functions:

log10(), math(), pow(), sqrt()

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MKS Toolkit 9.2 Documentation Build 16.