math:log10 - XPath XQuery Reference

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XPath/XQuery log10 function

Summary

Returns the base-ten logarithm of the argument.

Signature

math:log10(

$arg as xs:double?

) as xs:double?

Properties

This function is deterministic, context-independent, and focus-independent.

Rules

If $arg is the empty sequence, the function returns the empty sequence.

Otherwise the result is the base-10 logarithm of $arg, as defined in the specification of the log10 function applied to 64-bit binary floating point values.

The expression math:log10(()) returns ().

The expression math:log10(0) returns xs:double('-INF').

The expression math:log10(1.0e3) returns 3.0e0.

The expression math:log10(1.0e-3) returns -3.0e0.

The expression math:log10(2) returns 0.3010299956639812e0.

The expression math:log10(-1) returns xs:double('NaN').

The expression math:log10(xs:double('NaN')) returns xs:double('NaN').

The expression math:log10(xs:double('INF')) returns xs:double('INF').

The expression math:log10(xs:double('-INF')) returns xs:double('NaN').

The treatment of divideByZero and invalidOperation exceptions is defined in . The effect is that if the argument is zero, the result is -INF, and if it is negative, the result is NaN .