# Function Reference

# Log

Calculates the natural logarithm of a number.

Log ( expression )

## Parameters

expression | Any positive number.

## Return Value

Success: | the parameter's natural logarithm.
Failure: | Tends to return -1.#IND for non-positive parameters.

## Remarks

@error is always 0

## Related

Exp

## Example

    #include <MsgBoxConstants.au3>

    Example()

    Func Example()
        ; Assign a Local variable the natural logarithm of 1000.
        Local $fLog1 = Log(1000)

        ; Display the result.
        MsgBox($MB_SYSTEMMODAL, "", $fLog1)

        ; Assign a Local variable the base-10 natural logarithm of 1000.
        Local $fLog2 = Log10(1000)

        ; Display the result.
        MsgBox($MB_SYSTEMMODAL, "", $fLog2)
    EndFunc   ;==>Example

    ; User-defined function for common log
    Func Log10($fNb)
        Return Log($fNb) / Log(10) ; 10 is the base
    EndFunc   ;==>Log10