The pow() function computes the value of x raised to the power y, x^y. If x is negative, y must be an integer value.

Upon successful completion, pow() returns the value of x raised to the power y.

If x is 0 and y is 0, 1.0 is returned.

If y is NaN, or y is non-zero and x is NaN, NaN is returned. If y is 0.0 and x is NaN, NaN is returned.

If x is 0.0 and y is negative, -HUGE_VAL is returned and errno may be set to EDOM or ERANGE.

If the correct value would cause overflow, +-HUGE_VAL is returned, and errno is set to ERANGE.

If the correct value would cause underflow to 0, 0 is returned and errno may be set to ERANGE.

For exceptional cases, matherr(3M) tabulates the values to be returned as dictated by Standards other than XPG4.

The pow() function will fail if:

EDOM

The value of x is negative and y is non-integral.

ERANGE

The value to be returned would have caused overflow.

The pow() function may fail if:

EDOM

The value of x is 0.0 and y is negative.

ERANGE

The correct value would cause underflow.

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

See attributes(5) for descriptions of the following attributes:

exp(3M), isnan(3M), matherr(3M), attributes(5), standards(5)